TY - GEN A1 - Schneider, M. A1 - Meng, Birgit T1 - Ressourcenschonung bei der Zementherstellung am Beispiel des Einsatzes von Hüttensand PY - 2002 SN - 3-7640-0426-6 SP - 10 EP - 14 PB - Verlag Bau + Technik CY - Düsseldorf AN - OPUS4-2069 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Schießl, P. A1 - Meng, Birgit A1 - Adam, G. A1 - Rößler, G. A1 - Schröder, P. A1 - Schwamborn, B. A1 - Wallner, B. A1 - Wiegrink, K. ED - Zilch, K. ED - Diederichs, C. J. T1 - Baustoffe PY - 2002 SN - 3-540-65760-6 IS - Kap. 3.1 SP - 3-3-3-60 PB - Springer CY - Berlin AN - OPUS4-2070 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kühne, Hans-Carsten A1 - Maultzsch, Matthias A1 - Wolff, L. A1 - Meng, Birgit A1 - Raupach, M. ED - Maultzsch, M. T1 - Long-term performance of surface protection systems for concrete T2 - 11th International Congress on Polymers in Concrete (ICPIC `04) CY - Berlin, Germany DA - 2004-06-02 KW - Surface protection system KW - Concrete KW - Weathering KW - Water uptake KW - Freezethaw resistance KW - Chloride ingress KW - Carbonation KW - Hydrophobic treatment PY - 2004 SN - 3-00-013706-8 SP - 417 EP - 428 PB - BAM CY - Berlin AN - OPUS4-3602 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kühne, Hans-Carsten A1 - Maier, Bärbel A1 - Maultzsch, Matthias A1 - Meng, Birgit A1 - Meinhold, Uwe T1 - Verification of the suitability of shotcrete on low strength concrete surfaces T2 - 10th International Conference on Durability of Building Materials and Components (DBMC) CY - Lyon, France DA - 2005-04-17 KW - Hydraulic engineering structures KW - Low strength concrete KW - Repair systems KW - Performance tests PY - 2005 SP - 8 pages CY - Lyon AN - OPUS4-7413 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Urs A1 - Fontana, Patrick A1 - Meng, Birgit T1 - BAM-Division VII.1 Building Materials: Main Expertise/NANOCEM Partner Project T2 - Nanocem Open meeting CY - Morges, Switzerland DA - 2005-04-29 PY - 2005 AN - OPUS4-7420 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Urs A1 - Pliett, H. A1 - Wenzel, F. A1 - Meng, Birgit T1 - A sustainable approach for the conservation of the Timur Shah Mausoleum in Kabul, Afghanistan T2 - 10th International Conference on Durability of Building Materials and Components (DBMC) CY - Lyon, France DA - 2005-04-17 PY - 2005 SP - 1 EP - 8(?) CY - Lyon AN - OPUS4-7411 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fontana, Patrick A1 - Meng, Birgit A1 - Hillemeier, B. T1 - Frühe autogene Verformungen von HPC - Beurteilung des plastischen Schwindens und spannungsinduzierender Verformungen durch Korrelation mit der Hydratationskinetik N2 - Der Einfluß der Mischungszusammensetzungen auf das frühe autogene Schwinden der Bindemittelmatrix von Hochleistungsbetonen wurde durch Korrelation mit der Hydratationskinetik untersucht. Durch die Analyse der Verformungsgeschwindigkeiten konnte eine Unterscheidung zwischen plastischen und spannungsinduzierenden Verformungen vorgenommen werden. T2 - 45. Forschungskolloquium des DAfStb CY - Wien, Österreich DA - 06.10.2005 KW - Hochleistungsbeton KW - Autogenes Schwinden KW - Hydratation KW - Porenstruktur PY - 2005 SN - 0005-9900 SN - 1437-1006 VL - 100 SP - 57 EP - 60 PB - Ernst CY - Berlin AN - OPUS4-11177 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fontana, Patrick A1 - Meng, Birgit A1 - Habel, Wolfgang A1 - Wagenknecht, E. A1 - Hillemeier, B. T1 - Measurement of viscoelastic properties of cement pastes with oscillation rheometry T2 - 24th conference on Cement and Concrete Science CY - Warwick, England, UK DA - 2004-09-16 KW - Cement paste KW - Oscillation rheometry KW - Viscoelastic properties PY - 2004 SP - 1(?) EP - 4(?) AN - OPUS4-11178 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Urs A1 - Meng, Birgit A1 - Österle, Werner A1 - Gardei, André ED - Stark, J. T1 - Characterization of granulated blast furnace slag by means of the combined application of the FIB/TEM technique T2 - 16. Ibausil - Internationale Baustofftagung CY - Weimar, Germany DA - 2006-09-20 PY - 2006 SN - 3-00-018263-2 VL - 1 SP - 1-0189 - 1-0195 PB - Bauhaus-Univ. CY - Weimar AN - OPUS4-13717 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Weise, Frank A1 - Onel, Yener T1 - Feuchtemessung in kapillarporösen Baustoffen T2 - DAfStb Fachtagung "Betonbauten als Dichtkonstruktionen" CY - Berlin, Germany DA - 2004-03-12 PY - 2004 AN - OPUS4-5382 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Herbst, Tristan A1 - Meng, Birgit T1 - Ganzheitliche Eignungsbewertung potenzieller Recyclingwege für Mauerwerksrestmassen PY - 2013 SN - 978-3-433-03017-2 SN - 978-3-433-60296-6 SN - 0170-4958 VL - 38 IS - Kap. 2.2.6 SP - 637 EP - 641 PB - Ernst & Sohn AN - OPUS4-28564 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Huismann, Sven A1 - Weise, Frank A1 - Meng, Birgit A1 - Schneider, U. T1 - Transient strain of high strength concrete at elevated temperatures and the impact of polypropylene fibers N2 - This paper presents the results of an experimental study on the transient strain of high strength concrete (HSC) under heating up to 750 °C and the impact of polypropylene (PP) fibers. Concerning this topic only few results are available in the literature and systematic investigations are missing. However, basic knowledge is necessary for the understanding of the internal damage processes in the material as well as for heated structures. The transient strain during heating can be separated in two basic components: the free thermal strain and the mechanical strain. They were experimentally determined exemplarily for one HSC. For the determination of the mechanisms of transient strain and particularly the influence of PP fibers different techniques were applied. In this context the monitoring of the microcracking was done for the first time with acoustic emission analysis in combination with ultrasonic measurements. This new approach helps fundamentally to explain the impact of PP fibers on free thermal strain and mechanical strain during heating up. Furthermore weight loss measurements were carried out to characterize the moisture transport. It was shown that the PP fibers cause an acceleration of the moisture transport in the temperature range from 200 to 250 °C which leads to drying shrinkage in opposite direction to the free thermal strain. Hence this paper is a contribution to the general understanding of the impact of PP fibers in HSC at high temperatures and emphasizes the important influence of PP fibers on the thermal and mechanical induced strain of HSC. KW - High strength concrete KW - Polypropylene fibers KW - Elevated temperatures KW - Transient strain KW - Acoustic emission KW - Ultrasound PY - 2012 U6 - https://doi.org/10.1617/s11527-011-9798-6 SN - 1359-5997 SN - 1871-6873 VL - 45 IS - 5 SP - 793 EP - 801 PB - Springer CY - Dordrecht AN - OPUS4-26029 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pistol, Klaus A1 - Weise, Frank A1 - Meng, Birgit T1 - Polypropylen-Fasern in Hochleistungsbetonen - Wirkungsmechanismen im Brandfall N2 - Bauteile bzw. Tragwerke aus Hochleistungsbetonen müssen in der Regel gegen brandinduzierte Abplatzungen mit geeigneten Maßnahmen geschützt werden, um einen ausreichenden Feuerwiderstand im Brandfall zu gewährleisten. Die bisher wirtschaftlich und technologisch sinnvollste Methode zur Verhinderung von explosionsartigen Betonabplatzungen im Brandfall ist die Zugabe von Polypropylen-Fasern. Die Wirksamkeit der Fasern konnte zwar empirisch gezeigt werden, es stellt sich allerdings die Frage, welche Mechanismen zur Verhinderung der Abplatzungen führen. Der vorliegende Beitrag fasst bisherige Theorien zur Wirkungsweise von Polypropylen-Fasern in brandbeanspruchten Hochleistungsbetonen zusammen und stellt eine innovative Methodologie zur Erforschung der mikrostrukturellen Prozesse vor. Die Ergebnisse zeigen, dass die nach dem Schmelzen und Zersetzen der Polypropylen-Fasern frei werdenden Mikrokanäle durch eine gleichzeitig einsetzende Mikrorissbildung netzartig verbunden werden. Die Mikrorissbildung ermöglicht somit den Abbau von Eigen- und Zwangsspannungen im Beton (mechanischer Effekt) und die Entstehung eines Transportwegesystems für den ausströmenden Wasserdampf (Permeationseffekt).--------------------------------------------------------------------------- Structural members and bearing structures of high performance concrete generally have to be protected against explosive spalling due to fire exposure to guarantee a sufficient fire resistance. Up to now, the economically and technologically most worthwhile method to prevent explosive spalling is the addition of polypropylene fibres. Though the effectiveness of the fibres could be shown empirically, the mechanisms preventing explosive spalling are still debatable. The present article summarizes the existing theories concerning the mode of action of polypropylene fibres in fire exposed high performance concretes and presents an innovative methodology for analysing the micro structural processes. The results show that due to the thermal decomposition of the polypropylene fibres micro channels are created and simultaneously connected due to a netlike micro crack formation. This enables the relief of internal stresses (mechanical effect) and the formation of a permeable transport system for the escaping water vapour (permeation effect). KW - Polypropylen-Fasern KW - Brandschutz KW - Structural fire protection KW - Computertomographie KW - Computed tomography KW - Hochleistungsbeton KW - High performance concrete KW - Messtechnik KW - Mikrorisse KW - Micro cracks KW - Polypropylen-Fasern KW - Polypropylene fibres KW - PP-Fasern KW - Prüfmethoden KW - Rasterelektronenmikroskopie KW - Scanning electron microscopy KW - Risse KW - Schallemissionsanalyse KW - Acoustic emission KW - UHPC KW - Baustoffe KW - Brandschutz KW - Versuche PY - 2012 U6 - https://doi.org/10.1002/best.201200024 SN - 0005-9900 SN - 1437-1006 VL - 107 IS - 7 SP - 476 EP - 483 PB - Ernst CY - Berlin AN - OPUS4-26174 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Herbst, Tristan A1 - Rübner, Katrin A1 - Meng, Birgit A1 - Hauer, B. ED - Bager, D. H. ED - Silfwerbrand, J. T1 - Sustainable evaluation - concept to assess the applicability of secondary aggregates in concrete T2 - fib Symposium Stockholm 2012 'Concrete structures for a sustainable community' CY - Stockholm, Sweden DA - 2012-06-11 KW - Sustainability KW - Sustainable evaluation KW - Secondary aggregates KW - Concrete PY - 2012 SN - 978-91-980098-1-1 SP - 441 EP - 444 PB - Royal Institute of Technology CY - Stockholm AN - OPUS4-26316 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Wend, Dirk A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - The influence of superplasticiser modifications on early hydration processes N2 - Self-compacting concrete (SCC) differs substantially from normal concrete as regards the quantity of superplasticiser dosage. The functionality of superplasticisers, based on the polycarboxylate ether (PCE) superplasticiser customary with SCC, is nowadays very well understood at construction material research level. However, knowledge concerning pertinent correlations does not always permeate practice to an equal extent. PCEs are extremely polymorphic as opposed to earlier superplasticiser groups, which still possess a considerable proportion of the superplasticiser market. The geometry of polymers can be adjusted individually to performance characteristics required for certain uses. Yet, in selecting a superplasticiser for its specified rheological properties, a very strong influence can equally be exerted simultaneously on the subsequent hydration process. The charge density of the PCE employed also plays a key role in connection with both rheology and early hydration. KW - Rheology KW - Early cement hydration KW - Polycarboxylate ether vicat KW - Shrinkage PY - 2012 SN - 1437-9023 VL - 4 SP - 64 EP - 69 PB - ad-media-Verl. CY - Köln AN - OPUS4-26355 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Wend, Dirk A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - Einfluss der Fließmittelmdoifikation auf Prozesse während der frühen Hydratation von selbstverdichtenden Bindemitteln KW - Rheologie KW - Frühe Zementhydratation KW - Polycarboxylatether KW - Vicat KW - Schwinden PY - 2012 SN - 1439-7706 VL - 4 SP - 66 EP - 71 PB - ad-media-Verl. CY - Köln AN - OPUS4-26356 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Herbst, Tristan A1 - Meng, Birgit A1 - Rübner, Katrin T1 - Ganzheitliche Eignungsbewertung von Sekundärrohstoffen für den Einsatz in Beton N2 - Der Einsatz von Sekundärrohstoffen im Betonbau kann einen wesentlichen Beitrag zu einer nachhaltigen Ressourcenwirtschaft im Bauwesen leisten. Sekundärrohstoffe (Recycling-Baustoffe, RC-Baustoffe) finden bereits Anwendung als Roh- bzw. Brennstoffe in der Portlandzementklinkerherstellung, als Zementbestandteile, als Betonzusatzstoffe sowie als sekundäre Gesteinskörnungen in Beton. In einem Teilprojekt des DAfStb/BMBF-Verbundforschungsvorhabens 'Nachhaltig Bauen mit Beton' wurde das Einsatzpotenzial von Sekundärrohstoffen in Beton untersucht. Hierbei spielen sowohl technische als auch ökologische und ökonomische Fragestellungen eine wichtige Rolle. Vor diesem Hintergrund wurde eine Bewertungsgrundlage mit ganzheitlicher Betrachtung von Nachhaltigkeitsaspekten (Technik, Ökologie, Ökonomie) ausgearbeitet. Dieses Bewertungskonzept umfasst die vier Bewertungsschritte: I. Grundsätzliche Überlegungen, II. Vorteile für das nachhaltige Bauen, III. Alternative Bewertungswege und IV. Sensitivitätsanalysen. Das Bewertungskonzept wurde am Beispiel der bereits im Betonbau eingesetzten rezyklierten Gesteinskörnungen entwickelt.---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Nowadays there are several applications of secondary mineral materials and residues. In the framework of the German research project 'Sustainable Building with Concrete', a concept to assess the applicability of already used and new secondary materials in concrete has been developed. It considers sustainability aspects and includes the following four assessment steps: I. Basic considerations, II. Advantages for sustainable construction, III. Alternative paths of application, and IV. Sensitivity analysis. Depending on changing technical, ecological and economic aspects, the assessment has to be performed for changed technical, ecological and economic conditions as necessity arises. KW - Nachhaltigkeit KW - Baustoffe KW - Betontechnologie KW - Sustainability KW - Sustainable evaluation KW - Holistic concept KW - Secondary materials KW - Secondary aggregates KW - Concrete KW - Allgemeines PY - 2012 U6 - https://doi.org/10.1002/best.201200025 SN - 0005-9900 SN - 1437-1006 VL - 107 IS - 8 SP - 533 EP - 539 PB - Ernst CY - Berlin AN - OPUS4-26337 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten A1 - Meng, Birgit ED - Wang, K. ED - Shah, S.P. ED - Khayat, K. T1 - Casting process improvement by optimization of mixture composition and high range water reducing agent modification N2 - Since its invention in the early 1990’s, self-consolidating concrete has never become well established in the ready-mix sectors worldwide. The reason for this can be mainly found in the fact that the sophisticated compositions are sensitive against changing environments. This lack of robustness can be attributed to the interaction between cement hydration reaction and high range water reducing agent (HRWRA). Understanding the relevant mechanisms that control the initial flow performance as well as the flow retention helps optimizing SCC mixtures that perform either steadily in one specific environment or that perform largely similarly at steadily changing environments. This paper depicts how HRWRAs interact with clinker and hydration phases and discusses the important role of the charge density of a polycarboxylic HRWRA in the way the rheology is affected. Based on rheometric results and observations of the Vicat setting times, it is shown that increasing charge densities of the HRWRA and decreasing water to powder ratios (w/p) reduce the flow retention and have lesser retarding effect on the setting. Based on the discussion, optimization procedures for the mixture composition and the HRWRA modification are suggested to achieve optimized performance for varying environmental situations or highest robustness for specific conditions. T2 - SCC 2013 - 5th North American conference on the design and use of self-consolidating concrete CY - Chicago, IL, USA DA - 12.05.2013 KW - Polycarboxylate KW - Cement hydration KW - Adsorption KW - Mixture composition KW - Environmental conditions PY - 2013 SP - 1 EP - 10 AN - OPUS4-28581 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meng, Birgit A1 - Müller, Urs A1 - Garcia, O. A1 - Malaga, Katarina T1 - Performance of a new anti-graffiti agent used for immovable cultural heritage objects N2 - Cultural Heritage objects are in many cases invaluable and irrecoverable, therefore their protection is a prior goal. One threat arises by intentionally defacing such objects with graffiti. One possibility to face the imminent threat is the application of a surface protection in form of anti-graffiti systems (AGS). However, the knowledge about the performance and durability of AGS on substrates used for historical buildings is still fragmented. The goal of the presented study was to investigate the performance of a newly developed agent in comparison to a selection of commercial anti-graffiti agents on different substrates, which were used for historical buildings. Four commercial anti-graffiti agents with different chemical formulations were selected and tested with the new agent on different stone and brick substrates. The results showed clearly that AGS based on dense, water vapour impermeable coatings are not suitable to porous substrates such as sandstone, brick or porous limestone due to their impair of the hygric properties and the visual appearance of a substrate. The new agent could not completely reach the cleaning efficacy of the dense coatings but exhibited a much lower impact on the properties of the substrate and was therefore better compatible to historical surfaces. KW - Graffiti KW - Cultural Heritage KW - Anti-graffiti agent KW - Performance KW - Stone KW - Brick KW - Cleaning efficacy KW - Compatibility PY - 2014 U6 - https://doi.org/10.1080/15583058.2012.747116 SN - 1558-3058 SN - 1558-3066 VL - 8 IS - 6 SP - 820 EP - 834 PB - Taylor & Francis CY - Philadelphia, Pa., USA AN - OPUS4-28605 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ramge, Peter A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - Repair mortars for the restoration and reprofiling of natural stone elements in cultural heritage N2 - For the protection of the world's cultural heritage the restoration of listed buildings and monuments is an important task. In many cases the need to repair and reprofile natural stone elements occurs. Repair mortars for such applications have to match historicocultural interests as well as durability related and constructive interests. Currently a research project dealing with the development and optimisation of such mortars is set up at the BAM. Special focus is laid on the possibility of a modular adaption to match a vast variety of stone properties. Besides the development and lab scale testing of the mortar system, an in-situ application will be planned and executed. T2 - EWCHP-2011 - European workshop on cultural heritage preservation CY - Berlin, Germany DA - 26.09.2011 KW - Repair mortar KW - Natural stone KW - Stone restoration KW - Stone reprofiling KW - Modular system KW - Listed buildings and monuments PY - 2011 SN - 978-3-8167-8560-6 SP - 281 EP - 288 AN - OPUS4-24561 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Herbst, Tristan A1 - Rübner, Katrin A1 - Meng, Birgit A1 - Hauer, B. T1 - Assessment concept for the sustainable use of secondary aggregates in concrete N2 - Nowadays there are several applications of mineral recycling materials and residues. At present an assessment method for the use of secondary raw materials, which considers sustainability aspects, does not exist. In the framework of the German DAfStb/BMBF research project 'Sustainable Building with Concrete' an assessment concept was developed. It includes the following four assessment steps: I. Basic considerations, II. Advantages for sustainable construction, III. Alternative paths for application, and IV. Sensitivity analysis. The concept was developed on the basis of recycled concrete aggregates, which are already used according to German standards. Afterwards, it was applied and verified by the evaluation of the utilisation of municipal solid waste incinerator bottom ashes. T2 - International RILEM conference on advances in construction materials through science and engineering CY - Hong Kong, China DA - 05.09.2011 KW - Sustainability KW - Assessment KW - Secondary aggregates KW - Concrete PY - 2011 SN - 978-2-35158-116-2 VL - PRO 79 IS - Chapter 10 / Study of sustainable use... SP - 1 EP - 8 PB - RILEM Publications AN - OPUS4-24564 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ramge, Peter A1 - Kühne, Hans-Carsten A1 - Meng, Birgit ED - Grantham, M. ED - Mechtcherine, V. ED - Schneck, U. T1 - Influence of selected aspects of the mixture proportioning on the performance of repair mortars T2 - Concrete solutions 2011 - 4th International conference on concrete repair CY - Dresden, Germany DA - 2011-09-26 KW - Repair mortar KW - Concrete rehabilitation KW - Repair systems KW - Polymer cement concrete (PCC) KW - Sprayed polymer cement concrete (SPCC) PY - 2012 SN - 978-0-415-61-622-5 SP - 451 EP - 459 PB - Taylor & Francis CY - London AN - OPUS4-24567 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fontana, Patrick A1 - Müller, Urs A1 - Meng, Birgit ED - Rogge, A. ED - Meng, B. T1 - Schädigungsmechanismen in Beton T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Deutschland DA - 2011-11-07 KW - Frost-Tausalz-Beanspruchung KW - Schrumpfrisse KW - Autogenes Schwinden KW - Plastisches Schwinden KW - Brand KW - Sulfatangriff KW - AKR PY - 2011 SN - 978-3-9814281-0-0 IS - D1 SP - 105 EP - 110 PB - BAM Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-25141 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Müller, Urs A1 - Fontana, Patrick T1 - Neue Erkenntnisse und Analysemethoden zum Phasenbestand und Gefüge des Zementsteins T2 - 52.DAfStb-Forschungskolloquium, BAM CY - Berlin, Germany DA - 2011-11-07 PY - 2011 AN - OPUS4-25226 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ramge, Peter A1 - Kühne, Hans-Carsten A1 - Meng, Birgit ED - Rogge, A. ED - Meng, B. T1 - Rheologie von Instandsetzungsmörteln - aktuelle Untersuchungen mit dem Würpelgerät T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Germany DA - 07.11.2011 PY - 2011 SN - 978-3-9814281-0-0 SP - 58 EP - 66 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-25192 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Vasilic, Ksenija A1 - Kühne, Hans-Carsten A1 - Meng, Birgit A1 - Roussel, N. ED - Rogge, A. ED - Meng, B. T1 - Modelling of fresh SCC flow through reinforced sections T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Deutschland DA - 2011-11-07 PY - 2011 SN - 978-3-9814281-0-0 SP - 50 EP - 57 PB - BAM Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-25193 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten A1 - Meng, Birgit ED - Rogge, A. ED - Meng, B. T1 - Zum Einfluss des Mischungsentwurfs und des Fließmittels auf temperaturbedingte Veränderungen der Rheologie von SVB T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Deutschland DA - 2011-11-07 KW - Fließmittel KW - Polycarboxylatether KW - Selbstverdichtender Beton KW - Temperatureffekte KW - Rheologie PY - 2011 SN - 978-3-9814281-0-0 SP - 40 EP - 49 PB - BAM Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-25194 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten ED - Rogge, A. ED - Meng, B. T1 - Aktuelle Forschungsansätze zur Rheologie von Frischbeton T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Deutschland DA - 2011-11-07 KW - Baustoffe KW - Beton KW - Frischbeton KW - Rheologie PY - 2011 SN - 978-3-9814281-0-0 SP - 33 EP - 39 PB - BAM Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-25195 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lehmann, Christian A1 - Fontana, Patrick A1 - Müller, Urs A1 - Meng, Birgit ED - Rogge, A. ED - Meng, B. T1 - Entwicklung von C-S-H-Phasen in autoklaviertem Ultra-Hochleistungs-Beton (UHPC) T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Deutschland DA - 2011-11-07 PY - 2011 SN - 978-3-9814281-0-0 SP - 25 EP - 32 PB - BAM Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-25196 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schlegel, Moritz-Caspar A1 - Müller, Urs A1 - Panne, Ulrich A1 - Emmerling, Franziska A1 - Meng, Birgit ED - Rogge, A. ED - Meng, B. T1 - Neue Wege in der Zementanalytik - Hochaufgelöste in-situ Sy-XRD T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Deutschland DA - 2011-11-07 PY - 2011 SN - 978-3-9814281-0-0 SP - 18 EP - 24 PB - BAM Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-25197 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Müller, Urs A1 - Fontana, Patrick ED - Rogge, A. ED - Meng, B. T1 - Neue Erkenntnisse und Analysemethoden zum Phasenbestand und Gefüge des Zementsteins T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Deutschland DA - 2011-11-07 KW - Baustoffe KW - Zement KW - Mörtel KW - Mineralogische Zusammensetzung PY - 2011 SN - 978-3-9814281-0-0 SP - 11 EP - 17 PB - BAM Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-25198 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Voland, Katja A1 - Weise, Frank A1 - Meng, Birgit ED - Rogge, A. ED - Meng, B. T1 - Untersuchung des Einflusses der Gefügedichte von Betonen auf die AKR mit neuartiger Prüftechnik T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Deutschland DA - 2011-11-07 KW - Alkali-Kieselsäure-Reaktion KW - Nebelkammerlagerung bei 40° C KW - 60° C-Betonversuch KW - Dehnungsmessung KW - Schallemissionsanalyse KW - Ultraschallgeschwindigkeit KW - mu-3D-CT PY - 2011 SN - 978-3-9814281-0-0 SP - 86 EP - 95 PB - BAM Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-25199 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Barthel, Maria A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten A1 - Meng, Birgit ED - Rogge, A. ED - Meng, B. T1 - Betonpflastersteine mit erweiterten Leistungsmerkmalen T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Deutschland DA - 2011-11-07 PY - 2011 SN - 978-3-9814281-0-0 N1 - Geburtsname von Barthel, Maria: Meinel, M. - Birth name of Barthel, Maria: Meinel, M. SP - 194 EP - 203 PB - BAM Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-25182 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Huismann, Sven A1 - Korzen, Manfred A1 - Weise, Frank A1 - Meng, Birgit ED - Rogge, A. ED - Meng, B. T1 - Betonabplatzungen unter Feuerangriff und der Einfluss von Polypropylenfasern auf die Mikrorissbildung T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Germany DA - 07.11.2011 PY - 2011 SN - 978-3-9814281-0-0 SP - 163 EP - 171 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-25185 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Urs A1 - Meng, Birgit A1 - Bürgisser, Philip ED - Rogge, A. ED - Meng, B. T1 - Das natürliche Puzzolan 'Rheinischer Trass' und dessen Einfluss auf eine Alkali-Kieselsäure-Reaktion (AKR) in Beton T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Deutschland DA - 2011-11-07 PY - 2011 SN - 978-3-9814281-0-0 SP - 141 EP - 150 PB - BAM Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-25187 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pistol, Klaus A1 - Weise, Frank A1 - Meinel, Dietmar A1 - Meng, Birgit ED - Rogge, A. ED - Meng, B. T1 - Zur Wirkungsweise von Polypropylen-Fasern in brandbeanspruchten Hochleistungsbetonen T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Deutschland DA - 2011-11-07 KW - Polypropylen-Fasern KW - Hochfester Beton KW - Schallemissionsanalyse KW - Röntgen 3D-Computertomographie KW - Rasterelektronenmikroskopie PY - 2011 SN - 978-3-9814281-0-0 SP - 134 EP - 140 PB - BAM Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-25188 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Herbst, Tristan A1 - Rübner, Katrin A1 - Meng, Birgit ED - Rogge, A. ED - Meng, B. T1 - Ganzheitliche Bewertung der Einsatzmöglichkeiten von Sekundärrohstoffen in Beton T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Germany DA - 07.11.2011 PY - 2011 SN - 978-3-9814281-0-0 SP - 295 EP - 307 PB - BAM Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-25174 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rübner, Katrin A1 - Herbst, Tristan A1 - Meng, Birgit ED - Rogge, A. ED - Meng, B. T1 - Ressourcenschonung durch Reststoffverwertung im Betonbau T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Germany DA - 07.11.2011 PY - 2011 SN - 978-3-9814281-0-0 SP - 283 EP - 294 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-25175 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ramge, Peter A1 - Kühne, Hans-Carsten A1 - Meng, Birgit ED - Rogge, A. ED - Meng, B. T1 - Entwicklung von modularen Instandsetzungsmörteln für den Einsatz an denkmalgeschützten Natursteinbauwerken T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Germany DA - 07.11.2011 PY - 2011 SN - 978-3-9814281-0-0 SP - 247 EP - 255 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-25177 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ramge, Peter A1 - Kühne, Hans-Carsten A1 - Meng, Birgit ED - Rogge, A. ED - Meng, B. T1 - MODINSYS - Entwicklung und Modifikation von Instandsetzungsmörteln für Beton- und Stahlbetonkonstruktionen T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Germany DA - 07.11.2011 PY - 2011 SN - 978-3-9814281-0-0 SP - 238 EP - 246 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-25178 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ramge, Peter A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - Einfluss ausgewählter Modifikationen der Mischungszusammensetzung auf die Eigenschaften von Instandsetzungsmörteln N2 - Trotz der zahlreichen Möglichkeiten zur Beeinflussung der Mörteleigenschaften durch Mischungsmodifikationen ist es nahezu unmöglich, einzelne Eigenschaften unabhängig von anderen zu verändern. Bei einer Mischungsoptimierung muss im Einzelfall immer entschieden werden, welcher der gewünschten Eigenschaften die höchste Priorität zukommt. Anhand von Parameterstudien wird im vorliegenden Artikel verdeutlicht, wie es für bestimmte Anwendungen sinnvoll sein kann, die Verschlechterung einzelner Eigenschaften zu akzeptieren, wenn dadurch eine für den speziellen Einsatzfall essenzielle Eigenschaft verbessert werden kann. Die komplexen Wechselwirkungen der einzelnen Bestandteile fuhren dazu, dass auch scheinbar widersprüchliche Kombinationen von Zusatzmitteln im Einzelfall erforderlich werden können. Zur Anpassung der meisten Mörteleigenschaften gibt es verschiedene Möglichkeiten der Zielerreichung mit jeweils unterschiedlichen Nebeneffekten. Frisch- und Festmörteleigenschaften sind dabei gleichermaßen zu beachten. KW - Instandsetzungsmörtel KW - Betoninstandsetzung KW - Instandsetzungssysteme KW - Polymer-Zement Beton (PCC) KW - Polymer-Zement Spritzbeton (SPCC) KW - Repair mortar KW - Concrete rehabilitation KW - Repair systems KW - Polymer cement concrete (PCC) KW - Sprayed polymer cement concrete (SPCC) PY - 2011 SN - 1864-7251 SN - 0947-4498 VL - 17 IS - 3/4 SP - 169 EP - 180 PB - Aedificatio Publ. CY - Freiburg AN - OPUS4-24479 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Herbst, Tristan A1 - Rübner, Katrin A1 - Hauer, B. T1 - Assessment-concept for the sustainable use of secondary aggregates in concrete T2 - International Conference (RILEM-Week) on Advances in Construction Materials through Science and Energineering CY - Hong Kong, China DA - 2011-09-05 PY - 2011 AN - OPUS4-24470 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fontana, Patrick A1 - Lehmann, Christian A1 - Müller, Urs A1 - Meng, Birgit A1 - Kühne, Hans-Carsten A1 - Rogge, Andreas T1 - Wärmebehandlung und Autoklavierung von UHPC - Einfluss auf Mikrostruktur und mechanische Eigenschaften T2 - Feuerfestkolloquium 2011, Fachsymposium "Fertigteile aus UHPC - Fertigungspartner Feuerfestindustrie?" CY - Aachen, Germany DA - 2011-10-20 PY - 2011 AN - OPUS4-24745 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten T1 - Aktuelle Forschungsansätze zur Rheologie von Frischbeton T2 - 52. DAfStb-Forschungskolloquium, BAM CY - Berlin, Germany DA - 2011-11-07 PY - 2011 AN - OPUS4-25130 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - Zum Einfluss des Mischungsentwurfs und des Fließmittels auf temperaturbedingte Veränderungen der Rheologie von SVB T2 - 52. DAfStb-Forschungskolloquium, BAM CY - Berlin, Germany DA - 2011-11-07 PY - 2011 AN - OPUS4-25129 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pistol, Klaus A1 - Weise, Frank A1 - Meng, Birgit A1 - Schneider, U. ED - Koenders, E.A.B. ED - Dehn, F. T1 - The mode of action of polypropylene fibres in high performance concrete at high temperatures N2 - It has been shown in fire tests that polypropylene fibres reduce or avoid explosive spalling of high performance concrete. In the critical temperature ränge up to 300 °C the permeability of HPC increases by using polypropylene fibre. Due to this the water vapour, which is the main reason for explosive spalling, can escape. There exist different theories in the literature conceming the micro structural mechanisms, which cause an increase in the permeability. Within the framework of an internal research project at BAM an innovative methodology was developed for experimental verifying of existing theories and to get new insights into this problem The methodology used is unique and has been undertaken here for the first time. This consists of the combination of acoustic emission and ultrasonic measurement during temperature loading and the non-destructive micro structural analysis of cooled down samples with the aid of micro X-ray computed tomography. For the validation of the nondestructive test methods scanning electron microscopic images of prepared samples were undertaken. The results show that due to the thermal decomposition of the polypropylene fibres micro canals emerge. These are connected due to a simultaneous micro cack formation. T2 - 2nd International RILEM workshop on concrete spalling due to fire exposure CY - Delft, The Netherlands DA - 05.10.2011 KW - Spalling KW - Polypropylene fibres KW - High performance concrete KW - Acoustic emission KW - X-ray computed tomography KW - Scanning electron microscopy PY - 2011 SN - 978-2-35158-118-6 SP - 289 EP - 296 PB - RILEM Publications AN - OPUS4-24835 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ramge, Peter A1 - Kühne, Hans-Carsten A1 - Meng, Birgit ED - Drochytka, R. ED - Bohus, S. T1 - Natural stone reprofiling in cultural heritage with modular repair mortars N2 - Whenever the preservation of original substance obtains priority in a restoration task, reprofiling techniques using repair mortars are a welcome solution. For ordinary concrete repair aesthetic aspects are of minor importance whereas for the restoration of natural stone elements they come to the fore. Especially for listed buildings and monuments, historico-cultural and aesthetical interests become the ruling Parameters for planning and execution of restoration tasks. Nevertheless the technical and constructive requirements have to be considered and deterioration processes have to be understood to ensure sustainability and durability of the repair task. Due o differences in the Chemical and mineralogical composition, natural stone provides a vast variety of texture and colour. Also the range of different mechanical and durability related properties is far wider than found with concrete for example. A research project dealing with the development of a modular repair mortar System for natural stone is currently set up at the BAM. To provide the conservator with the best possible options to match colour, texture and technical requirements, the System will be setup on a modular basis. Several different binder Systems on basis of cement, lime and sodium Silicate as well as polymer based Systems are planned, which can be combined with different aggregate compositions and different pigments. To evaluate the mortar performance, test procedures will be defined for tests on mortar samples and on composite specimens. In the paper the experimental Programme will be explained and first results will be presented and discussed. T2 - 2nd WTA - Internaitonal PhD Symposium - Building materials and buidling technology to preserve the built heritage CY - Brno, Czech Republic DA - 06.10.2011 PY - 2011 SN - 978-3-937066-21-9 SN - 0947-6830 N1 - Serientitel: WTA-Schriftenreihe – Series title: WTA-Schriftenreihe IS - 36 SP - 208 EP - 216 PB - WTA Publications AN - OPUS4-24837 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fontana, Patrick A1 - Lehmann, Christian A1 - Müller, Urs A1 - Kühne, Hans-Carsten A1 - Meng, Birgit A1 - Rogge, Andreas T1 - Wärmebehandlung und Autoklavierung von UHPC - Neue Perspektiven für die Betonfertigteilindustrie T1 - Heat curing and autoclaving of UHPC - New perspectives for the precast concrete industry N2 - Das Gefüge von UHPC ist durch eine dicht gepackte und fehlstellenarme Matrix gekennzeichnet. Eine zusätzliche Optimierung ist durch eine Wärmebehandlung bzw. hydrothermale Nachbehandlung (Autoklavierung) unter einem Wasserdampfsättigungsdruck möglich. Die Wärmebehandlung von Beton ist ein in der Betonfertigteilindustrie geläufiges Verfahren, um die Erstarrungszeit zu verkürzen und höhere Frühfestigkeiten zu erreichen. N2 - The structure of UHPC is characterized by a densely packed matrix with only a small number of voids; it can be enhanced further by heat curing or hydrothermal Treatment (autoclaving) subject to water vapor pressure. Heat curing of concrete is commonly applied in the precast industry in Order to shorten its setting time and achieve higher early strengths. KW - Ultrahochleistungsbeton KW - Stahlfasern KW - Nachbehandlung KW - Mikrostruktur KW - Festigkeit PY - 2011 SN - 0373-4331 SN - 1865-6528 N1 - Sprachen: Deutsch/Englisch - Languages: German/English VL - 77 IS - 10 SP - 46 EP - 47 PB - Bauverl. CY - Gütersloh AN - OPUS4-24838 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Huismann, Sven A1 - Weise, Frank A1 - Meng, Birgit A1 - Schneider, U. T1 - Influence of polypropylene fibres on the thermal strain of high strength concrete at high temperatures N2 - This paper presents the results of an experimental study on the influence of polypropylene (PP) fibres on the thermal strain of high strength concrete (HSC) at temperatures up to 750°C. Concerning this topic only few results can be found in the literature and systematic investigations are missing. However, basic knowledge is necessary to understand the internal damage processes as well as for structural design. To explain the differences in the thermal strain of HSC with and without addition of PP fibres the internal damage processes were investigated with acoustic emission (AE) analysis and ultrasound (US). Furthermore the weight loss was measured continuously during heating to monitor the drying of the specimen. This novel approach by combining these different methods with strain measurements at high temperatures allows the integral description of the internal damage processes. The results reveal significant differences in the thermal strain of HSC when PP fibres are added. Between 200°C and 250°C the thermal strain of HSC with PP fibres is superimposed by shrinkage caused by accelerated drying. Above 250°C it is lower than that of plain HSC without PP fibres. It is supposed that it is caused by a more homogeneous distribution of micro cracks whereby the fibre beds acting as defects in the concrete. Hence this paper gives a contribution to the general understanding of the impact of PP fibres in HSC at high temperatures and points out the influence of the fibres on the thermal strain of HSC. KW - High performance concrete KW - High temperatures KW - Polypropylene fibres KW - Thermal strain KW - Acoustic emission KW - Ultrasound PY - 2011 U6 - https://doi.org/10.1260/2040-2317.2.3.173 SN - 2040-2317 VL - 2 IS - 3 SP - 173 EP - 179 PB - Multi-Science Publ. Co. CY - Brentwood AN - OPUS4-24817 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Herbst, Tristan A1 - Rübner, Katrin A1 - Meng, Birgit A1 - Hauer, B. T1 - Sustainable evaluation - concept to assess the applicability of secondary aggregates in concrete N2 - Nowadays there are several applications of mineral recycling materials and residues. At present an assessment method for the use of secondary raw materials, which considers sustainability aspects, does not exist. In the framework of the German DAfStb/BMBF research project “Sustainable Building with Concrete” an assessment concept was developed. It includes the following four assessment steps: I. Basic considerations, II. Advantages for sustainable construction, III. Alternative paths for application, and IV. Sensitivity analysis. The concept was developed on the basis of recycled concrete aggregates, which are already used according to German standards. Afterwards, it was applied and verified by the evaluation of the utilisation of municipal solid waste incinerator bottom ashes (referred to MSWI bottom ashes). T2 - 2011 Helsinki world sustainable building conference CY - Helsinki, Finland DA - 18.10.2011 KW - Sustainable building KW - Sustainability aspects KW - Secondary materials KW - Secondary aggregates in concrete KW - Energy and material resources KW - Assessment concept PY - 2011 SN - 978-951-758-534-7 SN - 0356-9403 SP - 1 EP - 8 AN - OPUS4-24781 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - Optimierung der Robustheit von selbstverdichtendem Beton gegenüber Temperatureinflüssen N2 - Selbstverdichtender Beton verhält sich unter Temperatureinfluss anders als Normalbeton, da die Rheologie neben der fortschreitenden Hydratation zusätzlich durch die von der Zeit und dem Hydratationsfortschritt abhängige Adsorption von Fließmitteln beeinflusst wird. Anhand rheometrischer Betonversuche an SVB unterschiedlicher Entwurfskonzepte mit variierter anionischer Ladungsdichte im Fließmittel wird verdeutlicht, dass mehlkornreiche SVB bei niedrigen Temperaturen sehr robust sind, während bei hohen Temperaturen mehlkornärmere Entwürfe zu bevorzugen sind. Darüber hinaus wird gezeigt, wie sich unterschiedliche Fließmittelmodifikationen in bestimmten Temperaturbereichen verhalten. Anhand des Wasser-Feststoff-Verhältnisses und des Adsorptionsverhaltens von Fließmitteln werden die maßgeblichen Prozesse erläutert und Möglichkeiten für die Entwicklung robuster Mischungen für individuelle Temperaturbereiche aufgeführt.-------------------------------------------------------------------------------------------------------------------------------------------------------------- Regarding the temperature dependent performance, self-compacting concrete (SCC) distinguishes from normal concrete, since its rheology does not only depend upon the hydration itself but supplementary upon the adsorption of superplasticizers, which is affected by the time and the hydration progress. Based on rheometric concrete investigations with different SCC mixture compositions and varied anionic charge densities of the superplasticizers, it is shown that SCC, which is rich in powder components, shows robust performance at low temperatures, while compositions with lower powder contents are favourable at high temperatures. Furthermore, the performance of different superplasticizer modifications at different temperature ranges is demonstrated. The relevant processes are explained by means of the water to powder ratio as well as the adsorption behaviour of superplasticizers, and options for the development of robust mixture compositions for individual temperature ranges are itemised. KW - Betontechnologie KW - Hochleistungsbeton KW - Praxis KW - Rheologie KW - Mischungsentwurf KW - Selbstverdichtender Beton KW - Fließmittel KW - Temperatur KW - Frischbetoneigenschaften KW - Robustheit KW - Baustoffe KW - Versuche PY - 2013 U6 - https://doi.org/10.1002/best.201200051 SN - 0005-9900 SN - 1437-1006 VL - 108 IS - 1 SP - 13 EP - 21 PB - Ernst CY - Berlin AN - OPUS4-27699 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vasilic, Ksenija A1 - Meng, Birgit A1 - Kühne, Hans-Carsten A1 - Roussel, N. T1 - Flow of fresh concrete through steel bars: a porous medium analogy N2 - Although being a very promising area of concrete technology, computational modeling of fresh concrete flow is a comprehensive and time consuming task. The complexity and required computation time are additionally increased when simulating casting of heavily reinforced sections, where each single reinforcement bar has to be modeled. In order to improve the computation speed and to get closer to a practical tool for simulation of casting processes, an innovative approach to model reinforced sections is proposed here. The basic idea of this approach is to treat the reinforcement zone as a porous medium in which a concrete is propagating. In the present paper, the numerical implementation of this concept is described. A methodology allowing for the computation of the equivalent permeability of the steel bars network is suggested. Finally, this numerical technique efficiency is evaluated by a comparison with experimental results of model fluids casting in model formworks. KW - Fresh concrete (A) KW - Rheology (A) KW - Modeling (E) KW - Permeability (C) KW - Yield stress KW - Simulation KW - Flow of mortar KW - Flow of concrete PY - 2011 U6 - https://doi.org/10.1016/j.cemconres.2011.01.013 SN - 0008-8846 SN - 1873-3948 VL - 41 IS - 5 SP - 496 EP - 503 PB - Pergamon Press CY - New York, NY AN - OPUS4-25532 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Fontana, Patrick A1 - Müller, U. A1 - Bürgisser, P. ED - Uzoegbo, H.C. ED - Schmidt, Wolfram T1 - Influence of natural pozzolans on the risk of alkali silica reaction N2 - Industrial byproducts and natural pozzolanas are increasingly being used as supplementary cementitious materials. In the group of natural pozzolanas volcanic ashes are the most prominent. Despite the fact that volcanic pozzolanas were used since Roman times, not much is known about their role in influencing the long term durability of concrete. The paper presents results of the volcanic pozzolana ‘Rhenish trass’, which is quarried in western Germany and its role during an alkali silica reaction (ASR). Field data and laboratory experiments indicate that trass releases alkalis into the pore solution but also changes cement paste chemistry and alkali binding behavior. There seems to be a sensitive balance between alkali release and increase of alkali binding capacity, both mechanisms crucial for the course of an ASR in concrete. T2 - ACCTA - International conference on advances in cement and concrete technology in Africa 2013 CY - Johannesburg, South Africa DA - 28.01.2013 KW - Alkali silica reaction KW - Natural pozzolans KW - Microscopy KW - Micro chemical analysis PY - 2013 SN - 978-3-9815360-3-4 SP - 801 EP - 808 AN - OPUS4-27765 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Fontana, Patrick A1 - Müller, Urs A1 - Kühne, Hans-Carsten T1 - Nanotechnologie im Bauwesen T2 - Jährliche Fachveranstaltung des deutschen Beton- und Bautechnik-Vereins (DBV) - Hauptausschuss Betontechnologie Veranstalter:DBV, BAM -VII:1 CY - Berlin, Germany DA - 2007-06-20 PY - 2007 AN - OPUS4-14995 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wiens, U. A1 - Meng, Birgit A1 - Fontana, Patrick T1 - Mikrorissbildung in Hochleistungsbeton - Vom Modell zu den Auswirkungen auf Betoneigenschaften KW - Hochleistungsbeton KW - Silikastaub KW - Mikrorissbildung PY - 2007 SN - 0005-9846 VL - 57 IS - 6 SP - 256 EP - 265 PB - Verlag Bau + Technik CY - Erkrath AN - OPUS4-15009 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kühne, Hans-Carsten A1 - Schmidt, Wolfram A1 - Meng, Birgit T1 - The influence of temperature on self-compacting concrete in presence of superplasticizer and additional admixtures T2 - 5th International RILEM Symposium on Self-Compacting Concrete CY - Ghent, Belgium DA - 2007-09-03 KW - Influence of temperature KW - Self-compacting concrete KW - SCC KW - Superplaticizer KW - Admixtures PY - 2007 SN - 978-2-35158-050-9 VL - 1 SP - 405 EP - 410 CY - Bagneux, France AN - OPUS4-15897 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Meng, Birgit A1 - Fontana, Patrick A1 - Müller, Urs ED - D. Stephan, T1 - Nano-Gefügeanalytik als Optimierungsgrundlage für innovative Baustoffe - am Beispiel zementgebundener Baustoffe KW - Nanotechnologie KW - Analytik KW - Gefüge KW - Zement KW - Beton PY - 2007 SN - 3-89958-348-9 IS - 8 SP - 36 EP - 49 PB - Kassel University Press GmbH CY - Kassel AN - OPUS4-16363 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Weise, Frank A1 - Meng, Birgit ED - Jürgen Berger, ED - Fischer, Andreas ED - Stefan Himburg, ED - Michael Kramp, T1 - Einsatz innovativer Verfahren der Bauwerksdiagnose für die Bestandserfassung - ausgewählte Fallbeispiele T2 - Berliner Hoch- und Ingenieurbaukolloquium BHIK 07 "Bauen im Bestand - Innovationen aus Wissenschaft und Praxis" CY - Berlin, Deutschland DA - 2007-11-23 KW - Bauwerksdiagnose KW - Zerstörungsfreie Prüfung KW - Radar KW - Ultraschall KW - Röntgen-Computertomografie PY - 2007 SN - 978-3-8322-6723-0 SN - 0945-067X SP - 27 EP - 46 PB - Shaker CY - Aachen AN - OPUS4-16325 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bahlmann, Stefanie A1 - Rübner, Katrin A1 - Meng, Birgit A1 - Hauer, B. A1 - Klein, H. A1 - Müller, C. A1 - Ruppert, J. A1 - Schäfer, S. A1 - Spanka, G. A1 - Wassing, W. A1 - Zunzer, U. T1 - Potenziale des Sekundärstoffeinsatzes im Betonbau - Teilprojekt B1 KW - Nachhaltigkeit KW - Sekundäre Gesteinskörnung KW - Rezyklierte Gesteinskörnung KW - Betonbrechsand KW - Müllverbrennungsasche PY - 2007 SN - 978-3-410-65772-9 SN - 0171-7197 N1 - Geburtsname von Bahlmann, Stefanie: Ramolla, S. - Birth name of Bahlmann, Stefanie: Ramolla, S. IS - 572 SP - 131 EP - 222 PB - Beuth AN - OPUS4-16361 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Meng, Birgit A1 - Fontana, Patrick A1 - Müller, Urs T1 - Nanotechnologie im Beton - Entwicklungsstand und Innovationschancen KW - Nanotechnologie KW - Analytik KW - Gefüge KW - Zement KW - Beton PY - 2008 SN - 978-3-7625-3624-6 VL - 56 SP - 186 EP - 190 PB - Bauverlag BV CY - Gütersloh AN - OPUS4-16316 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Urs A1 - Meng, Birgit A1 - Kühne, Hans-Carsten A1 - Nemecek, J. A1 - Fontana, Patrick ED - E. Fehling, ED - Schmidt, M. ED - S. Stürwald, T1 - Micro texture and mechanical properties of heat treated and autoclaved Ultra High Performance Concrete (UHPC) KW - Ultra high performance concrete KW - Micro texture KW - Mechanical strength KW - Secondary cemetitious materials PY - 2008 SN - 978-3-89958-376-2 IS - 10 SP - 213 EP - 220 CY - Kassel AN - OPUS4-16726 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Müller, Urs A1 - Maier, Bärbel T1 - Vermeidung stofflicher Probleme bei der Wärmebehandlung von Beton T2 - "Beton für alle Wetter" Fachseminar CY - Berlin, Germany DA - 2005-11-24 PY - 2005 AN - OPUS4-11473 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Fontana, Patrick A1 - Meng, Birgit ED - Jensen, O. T1 - Influence of mix composition on early-age autogenous deformations of cement pastes T2 - International RILEM Conference on Volume Changes of Hardening Concrete: Testing and Mitigation CY - Lyngby, Denmark DA - 2006-08-20 KW - Autogenes Schwinden KW - Hochleistungsbeton KW - Hydratation KW - Porenstruktur KW - Zusatzstoffe KW - Zusatzmittel PY - 2006 SN - 2-351-58004-4 SP - 261 EP - 272 PB - RILEM Publications CY - Bagneux AN - OPUS4-12672 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Fontana, Patrick A1 - Müller, Urs T1 - Nano-Gefügeanalytik als Optimierungsgrundlage für innovative Baustoffe T2 - Fachtagung "Nanotechnologie im Bauwesen - Nanooptimierte Hightech-Baustoffe" CY - Kassel, Germany DA - 2007-05-09 PY - 2007 AN - OPUS4-14851 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bahlmann, Stefanie A1 - Rübner, Katrin A1 - Meng, Birgit T1 - Untersuchungen zur Verwertung industrieller Reststoffe als Primärrohstoffsubstitut in Mörtel und Beton T2 - GDCh-Fachtagung Bauchemie CY - Siegen, Deutschland DA - 2007-09-27 KW - Verwertungspotential KW - Industrielle Reststoffe KW - Filterrückstand KW - Papierasche KW - Biomasseasche KW - Edelstahlschlacke KW - Zumahlstoff KW - Betonzusatzstoff PY - 2007 SN - 3-936028-50-8 N1 - Geburtsname von Bahlmann, Stefanie: Ramolla, S. - Birth name of Bahlmann, Stefanie: Ramolla, S. VL - 37 SP - 237 EP - 244 AN - OPUS4-16095 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Urs A1 - Meng, Birgit A1 - Fontana, Patrick T1 - Nano-Gefügeanalytik - Die Optimierung von Baustoffen KW - Nanotechnologie KW - Baustoffe PY - 2008 SN - 1618-7881 VL - 1 IS - 1 SP - 18 EP - 21 PB - GIT Verl. CY - Darmstadt AN - OPUS4-17438 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brockmann, T. A1 - Fontana, Patrick A1 - Meng, Birgit A1 - Müller, Urs T1 - Nanotechnologie im Bauwesen N2 - Zu den Zielen der Nanotechnologie gehört die Entwicklung, Produktion und Anwendung von Materialien und Werkstoffen mit völlig neuartigen Leistungsspektren. Für die Baupraxis und die Materialforschung lassen sich über den Einsatz der Nanotechnologie Ziele wie die Optimierung von Baustoffeigenschaften, Vermeidung von Schäden und neue Funktionalitäten definieren. Der vorliegende Beitrag gibt einen Überblick über mögliche Anwendungsbereiche der Nanotechnologie im Bausektor, wie z. B. zementgebundene Baustoffe, Außen- und Dachfassaden, Fenster und Verglasungen, Brandschutz, Inneneinrichtung und Infrastrukturbau. Zudem werden aktuelle Forschungsarbeiten mit nanowissenschaftlichem und nanotechnologischem Schwerpunkt im Bereich baustoffbezogener Materialien der Bundesanstalt für Materialforschung und -prüfung (BAM) in Berlin vorgestellt. Die Forschungstätigkeiten beziehen sich zum einen auf die Modifikation der Hydratphasen in Ultra-Hochleistungsbeton (UHPC) und zum anderen auf die Weiterentwicklung von Anti-Graffiti-Systemen. KW - Nanotechnologie KW - Forschung und Entwicklung KW - UHPC KW - Anti-Graffiti PY - 2008 U6 - https://doi.org/10.1002/best.200800624 SN - 0005-9900 SN - 1437-1006 VL - 103 IS - 7 SP - 446 EP - 454 PB - Ernst CY - Berlin AN - OPUS4-17731 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Weise, Frank A1 - Pirskawetz, Stephan A1 - Meng, Birgit ED - L. Binda, ED - M. di Prisco, ED - R. Felicetti, T1 - Application of innovative testing methods for the quasi non-destructive assessment of the material condition in hydraulic engineering structures T2 - First Internatonal RILEM Symposium "on Site Assessment of Concrete, Masonry and Timber Structures" (SACoMaTiS 2008) CY - Varenna, Italy DA - 2008-09-01 KW - Quasi non-destructive assessment KW - Hydraulic engineering structures KW - Radar KW - Ultrasonic and ray PY - 2008 SN - 978-2-35158-062-2 VL - 1 IS - PRO 59 SP - 1 EP - 10 PB - RILEM Publications AN - OPUS4-18356 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten A1 - Meng, Birgit ED - Toutlemonde, F. ED - et al., T1 - Performance and interactions of admixtures for SCC exposed to different climatic conditions T2 - Fifth International Conference on Concrete under Severe Conditions: Environment and Loading (CONSEC `07) CY - Tours, France DA - 2007-06-04 PY - 2007 SN - 1628-4704 VL - 2 SP - 979 EP - 986 CY - Tours, France AN - OPUS4-15050 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Fontana, Patrick A1 - Müller, Urs A1 - Kühne, Hans-Carsten T1 - Nanotechnologische Anwendungen im Baustoffbereich T2 - Nanotechnologie und Bauwesen (NanoTecture) CY - Düsseldorf DA - 2006-12-05 KW - Nanotechnologie KW - Analytik KW - Gefüge KW - Zement KW - Beton PY - 2006 SP - 13 EP - 27 CY - Düsseldorf AN - OPUS4-15703 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fontana, Patrick A1 - Pirskawetz, Stephan A1 - Weise, Frank A1 - Meng, Birgit T1 - Detection of early-age cracking due to restrained autogenous shrinkage T2 - Symposium "Advances in Construction Materials" (ACM) CY - Stuttgart DA - 2007-07-23 KW - Hochleistungsbetone KW - Autogenes Schwinden KW - Frühe Rissbildung KW - Schallemissionsanalyse PY - 2007 SN - 978-3-540-72447-6 SP - 489 EP - 496 PB - Springer CY - Stuttgart AN - OPUS4-15708 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weise, Frank A1 - Pirskawetz, Stephan A1 - Müller, Urs A1 - Meng, Birgit T1 - Charakterisierung der Schädigungsprozesse in Betonen mit innovativen Prüftechniken KW - Beton KW - Naturstein KW - Schadensanalyse KW - Innovative Prüftechnik PY - 2007 IS - 13 SP - 14 EP - 20 AN - OPUS4-15715 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weise, Frank A1 - Pirskawetz, Stephan A1 - Müller, Urs A1 - Meng, Birgit T1 - Charakterisierung der Schädigungsprozesse in Betonen mit innovativen Prüftechniken KW - Beton KW - Schädigungsprozesse KW - Zerstörungsarme und zerstörungsfreie Prüfverfahren PY - 2006 SN - 0005-9846 VL - 56 IS - 6 SP - 268 EP - 275 PB - Verlag Bau + Technik CY - Erkrath AN - OPUS4-14403 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kühne, Hans-Carsten A1 - Haamkens, Frank A1 - Maultzsch, Matthias A1 - Meinhold, Uwe A1 - Meng, Birgit ED - Stark, J. T1 - Instandsetzung von Beton mit geringen Festigkeiten T2 - 16. Ibausil - Internationale Baustofftagung CY - Weimar, Germany DA - 2006-09-20 KW - Wasserbau KW - Beton mit geringer Festigkeit KW - Instandsetzung KW - Leistungsfähigkeit PY - 2006 SN - 3-00-018263-2 IS - Band 2 SP - 2-1173 - 2-1180 PB - Bauhaus-Univ. CY - Weimar AN - OPUS4-14475 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Fontana, Patrick A1 - Müller, Urs A1 - Kühne, Hans-Carsten T1 - Nanotechnologische Anwendungen in Baustoffen T2 - Fachgespräch "Nanotechnologie im Bauwesen (Nanoexture) CY - Düsseldorf, Germany DA - 2006-12-05 PY - 2006 AN - OPUS4-14526 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Kühne, Hans-Carsten A1 - Schmidt, Wolfram T1 - Introduction to the MicroCon project T2 - Internationales und öffentliches Kolloquium "New Economical and Ecological Solutions to Reduce Raw Material Costs of Cement Based Products by Utilizing Micro Technology" CY - Berlin, Germany DA - 2006-11-29 PY - 2006 AN - OPUS4-14527 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weise, Frank A1 - Meng, Birgit T1 - Identifikation von Schädigungsprozessen in Beton mit innovativen Prüftechniken T2 - Fachtagung des DAfStb "Neue Entwicklungen im Betonbau" CY - Berlin, Germany DA - 2007-03-08 PY - 2007 AN - OPUS4-14608 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Fontana, Patrick A1 - Müller, Urs T1 - Nanotechnologische Anwendungen im Baustoffbereich T2 - Branchendialog "Nanotechnologie in der Bauwirtschaft" Bundesmininsterium f. Wirtschaft u. Technologie CY - Berlin, Germany DA - 2007-11-02 PY - 2007 AN - OPUS4-16172 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Weise, Frank T1 - Einsatz innovativer Verfahren der Bauwerksdiagnose für die Bestandserfassung - ausgewählte Beispiele T2 - Berliner Hoch- und Ingenieurbaukolloquium BHK 07 "Bauen im Bestand" CY - Berlin, Germany DA - 2007-11-23 PY - 2007 AN - OPUS4-16443 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Meng, Birgit A1 - Kühne, Hans-Carsten A1 - Rosignoli, D. T1 - Development and application of a novel ready-made compound including additions and admixtures for the easy production of SCC - Entwicklung und Anwendung einer neuartigen Werktrockenmischung aus Zusatzstoffen und Zusatzmittel für die einfache Herstellung von SVB N2 - Im Rahmen des europäischen Forschungsprojekts Microcon wurden wirtschaftliche und ökologische Ansätze zur Verwendung von Feinstfüllstoffen – so genannten Microfillern – in Bauprodukten, die auf zementgebundenen Systemen basieren, untersucht. Hauptzielsetzung war die Entwicklung von modifizierten Bindemitteln und Zusätzen für die Transportbeton- und Fertigteilindustrie bis hin zur Marktreife. Eine der Neuentwicklungen war eine leicht handhabbare Werktrockenmischung für selbstverdichtenden Beton (SVB), die alle Schlüsselkomponenten bis auf das Bindemittel und die grobe Gesteinskörnung enthält und eine hohe Robustheit in der Anwendung gewährleistet. KW - Self-Compacting Concrete KW - Robustness KW - Microfiller KW - Rheology KW - On-Site Application III KW - Selbstverdichtender Beton KW - Robustheit KW - Mikrofiller KW - Rheologie KW - Baustellenanwendung PY - 2008 SN - 0373-4331 N1 - Sprachen: Deutsch/Englisch - Languages: German/English IS - 3 SP - 4 EP - 11 PB - Bauverl. BV CY - Gütersloh AN - OPUS4-17125 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit T1 - Mikrostruktur und Dauerhaftigkeit zementgebundener Baustoffe T2 - 8. Münchener Baustoffseminar "Dauerhaftigkeit von Betonkonstruktionen - Von den Mechanismen zum Lebensdauermanagement" CY - Munich, Germany DA - 2008-10-10 PY - 2008 AN - OPUS4-18201 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weise, Frank A1 - Meng, Birgit A1 - Pirskawetz, Stephan A1 - Müller, Urs T1 - Charakterisierung von Schädigungsprozessen in Betonen mit innovativer Prüftechnik T2 - VDB-Fachtagung 2006 "Beton-Entwicklungen und Tendenzen" CY - Bergisch Gladbach, Germany DA - 2006-04-27 PY - 2006 AN - OPUS4-12372 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Vasilic, Ksenija A1 - Roussel, N. A1 - Meng, Birgit A1 - Kühne, Hans-Carsten ED - Olafur H. Wallevik, ED - Stefan Kubens, ED - Sonja Oesterheld, T1 - Computational modelling of SCC flow: Reinforcement network modelled as porous medium T2 - 3rd International RILEM symposium on rheology of cement suspensions such as fresh concrete CY - Reykjavik, Iceland DA - 2009-08-19 KW - SCC KW - Modelling KW - CFD PY - 2009 SN - 978-2-35158-091-2 IS - PRO 68 SP - 148 EP - 154 PB - RILEM Publications AN - OPUS4-20238 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Rübner, Katrin A1 - Meng, Birgit A1 - Müller, Urs ED - Maierhofer, C. ED - Reinhardt, H.-W. ED - Dobmann, G. T1 - Investigating the original water content of concrete N2 - This chapter provides an overview of methods that are commonly used for the analysis of the original water content of fresh and hardened concrete. The methods consist of direct methods, which detect the water content or the water/cement ratio primarily, as well as indirect methods, which measure other material characteristics related to the water content. KW - Concrete analysis KW - Water content KW - Water/cement ratio KW - Pore structure analysis PY - 2010 SN - 978-1-84569-560-6 VL - 1 IS - Chapter 11 SP - 217 EP - 241 PB - Woodhead Publishing Ltd CY - Oxford AN - OPUS4-21814 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ramge, Peter A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - Development of a modular system for the protection and repair of concrete structures KW - Repair mortar KW - Repair systems KW - Polymer cement concrete (PCC) KW - Sprayed polymer cement concrete (SPCC) PY - 2010 SN - 1864-7251 SN - 0947-4498 VL - 16 IS - 4/5 SP - 387 EP - 400 PB - Aedificatio Publ. CY - Freiburg AN - OPUS4-22773 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Urs A1 - Lehmann, Christian A1 - Fontana, Patrick A1 - Meng, Birgit T1 - Effects of autoclaving on the nano structure and phase composition of ultra high performance concrete T2 - 12th Euroseminar on microscopy applied to building materials CY - Dortmund, Germany DA - 2009-09-15 KW - UHPC KW - Micro structure KW - Autoclaving KW - Phase stability KW - C-S-H PY - 2009 SN - 978-3-00-028697-1 SP - 351 EP - 359 AN - OPUS4-20622 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - Temperature related effects on self-consolidating concrete due to interactions between superplasticizers, supplemental admixtures and additions T2 - 9th ACI International conference on superplasticizers and other chemical admixtures in concrete CY - Seville, Spain DA - 2009-10-12 KW - Polycarboxylate KW - Modified starch KW - Rheology KW - Self-compacting concrete KW - Temperature KW - Setting KW - Shrinkage KW - Heat evolution PY - 2009 SN - 978-0-9731507-8-0 SP - 135 EP - 147 AN - OPUS4-20884 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Ramge, Peter A1 - Kühne, Hans-Carsten A1 - Meng, Birgit ED - Aguiar, J. B. ED - Jalali, S. ED - Camoes, A. ED - Ferreira, R.M. T1 - MODINSYS modular systems for the protection and repair of concrete structures T2 - 13th International Congress on polymers in concrete - ICPIC 2010 CY - Funchal-Madeira, Portugal DA - 2010-02-11 KW - Betoninstandsetzung KW - Instandsetzungsmörtel KW - Modulare Systeme KW - SPCC KW - PCC KW - Repair mortar KW - Modular systems KW - Concrete rehabilitation PY - 2010 SN - 978-972-99179-4-3 SP - 697 EP - 704 CY - Funchal-Madeira, Portugal AN - OPUS4-20937 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Meng, Birgit A1 - Müller, Urs A1 - Rübner, Katrin ED - Maierhofer, C. ED - Reinhardt, H.-W. ED - Dobmann, G. T1 - Components in concrete and their impact on quality: an overview KW - Concrete KW - Cement KW - Aggregate KW - Microstructure KW - Durability PY - 2010 SN - 978-1-84569-560-6 VL - 1 IS - Chapter 5 SP - 82 EP - 93 PB - Woodhead Publishing Ltd CY - Oxford AN - OPUS4-21049 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Müller, Urs A1 - Meng, Birgit A1 - Rübner, Katrin ED - Maierhofer, C. ED - Reinhardt, H.-W. ED - Dobmann, G. T1 - Analysis of solid components and their ratios in reinforced concrete structures KW - Concrete analysis KW - Concrete petrography KW - Optical microscopy KW - Scanning electron microscopy KW - Micro X-ray fluorescence analysis PY - 2010 SN - 978-1-84569-560-6 VL - 1 IS - Chapter 9 SP - 180 EP - 197 PB - Woodhead Publishing Ltd CY - Oxford AN - OPUS4-21050 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Schmidt, Wolfram A1 - Brouwers, J. A1 - Kühne, Hans-Carsten A1 - Meng, Birgit ED - Khayat, K. H. ED - Feys, D. T1 - Effects of superplasticizer and viscosity-modifying agent on fresh concrete performance of SCC at varied ambient temperatures N2 - Varying ambient temperatures in plants or on construction sites during casting of SCC can cause serious problems affecting the fresh concrete performances, such as rheological properties and setting time, with consequences for the hardened properties in the structure. By sensible choices of the components, the robustness of SCC mixtures against temperature variations can be improved. However, this aspect has not been the focus of intensive research yet. In this study the effects of varied ambient temperatures on the early performance of differently composed SCC mixtures are investigated, with emphasis on changes in rheology, early deformations, heat evolution and setting. Focus is placed on the study of the influence of the polycarboxylate ether molecule type as well as different viscositymodifying agents on the temperature robustness. Effects on the relevance for practical concrete applications are evaluated, which will provide a reliable framework of possible actions on the appropriate use of admixtures for SCC. T2 - SCC 2010 - 6th International RILEM Symposium on self-compacting concrete / 4th North American conference on the design and use of SCC - Desgin, Production and Placement of self-consolidating concrete CY - Montreal, Canada DA - 2010-09-26 KW - Polycarboxylate KW - Modified starch KW - Rheology KW - Self-compacting concrete KW - Temperature KW - Yield stress KW - Viscosity PY - 2010 SN - 978-90-481-9663-0 U6 - https://doi.org/10.1007/978-90-481-9664-7_6 N1 - Serientitel: RILEM bookseries – Series title: RILEM bookseries VL - 1 IS - 2 SP - 65 EP - 77 PB - Springer AN - OPUS4-22126 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Vasilic, Ksenija A1 - Roussel, N. A1 - Meng, Birgit A1 - Kühne, Hans-Carsten ED - Khayat, K.H. ED - Feys, D. T1 - Computational modeling of SCC flow through reinforced sections N2 - Computational modeling of fresh SCC flow is a comprehensive and time consuming task. The computational time is additionally increased when simulating casting of reinforced sections, where each single reinforcement bar has to be modeled. In order to deal with this issue and to decrease the computational time, an innovative approach of treating a reinforcement network as a porous medium is applied. This contribution presents the model for concrete flow through reinforced sections, based on Computational Fluid Dynamics (CFD), coupling a single-phase flow model for SCC and a continuum macroscopic model for porous medium. In the last part of this paper, numerical simulations are compared with experimental results obtained on model fluids. T2 - SCC2010 - Design, production and placement of self-consolidating concrete CY - Montreal, Canada DA - 2010-09-26 PY - 2010 SN - 978-90-481-9663-0 U6 - https://doi.org/10.1007/978-90-481-9664-7_16 N1 - Serientitel: RILEM bookseries – Series title: RILEM bookseries VL - 1 IS - 5 SP - 187 EP - 195 PB - Springer AN - OPUS4-22277 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - Influence of environmental temperatures on the performance of polymeric stabilising agent in fresh cementitious materials N2 - Stabilising admixtures are commonly used additives in repair mortars and grouts. Beyond this, such type of admixture is increasingly used in concrete and other cementitious materials. In particular when fresh mortar or concrete properties have to be adjusted reliably, stabilising agents can be beneficially used to improve workability and robustness of the mixture. The mode of operation of these admixtures varies, rather affecting either the liquid phase or the solid particles in the dispersion, both causing strong interactions with the mortar or concrete system, and significant changes in their rheological behaviour. Furthermore, these are strongly affected by the environmental temperature during the casting process. In the paper the effect of temperature on the performance of stabilising agents in cementitious systems is presented and how performance changes affect fresh and hardening mortar or concrete properties. Particular attention is placed on interactions between stabilising agents and superplasticizers. Results are discussed with special focus on self-compacting concrete. KW - Biopolymers KW - Cementitious materials KW - Polycarboxylate ether KW - Rheology KW - Setting KW - Stabilising agent KW - Starch ether KW - Self-compacting concrete KW - Superplasticizer PY - 2011 U6 - https://doi.org/10.4028/www.scientific.net/KEM.466.97 SN - 1013-9826 VL - 466 SP - 97 EP - 104 PB - Trans Tech Publ. CY - Aedermannsdorf AN - OPUS4-22853 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Ramge, Peter A1 - Kühne, Hans-Carsten A1 - Meng, Birgit ED - Littmann, K. T1 - Parameterstudien zum Einfluss von Rezepturveränderungen auf Schwindverhalten, Rissneigung und Steifigkeit mineralischer Instandsetzungsmörtel T2 - 7. Internationales Kolloquium Industrieböden 2010 CY - Ostfildern, Deutschland DA - 2010-12-14 KW - Betoninstandsetzung KW - Instandsetzungsmörtel KW - Modulare Systeme KW - Haftverbund KW - SPCC KW - PCC PY - 2010 SN - 3-924813-85-X IS - Kap. 2.6 SP - 191 EP - 200 AN - OPUS4-22845 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Ramge, Peter A1 - Kühne, Hans-Carsten A1 - Meng, Birgit ED - Raupach, M. T1 - Einfluss ausgewählter Modifikationen der Mischungszusammensetzung auf die Eigenschaften von Instandsetzungsmörteln N2 - Trotz der zahlreichen Möglichkeiten zur Beeinflussung der Mörteleigenschaften durch Mischungsmodifikationen ist es nahezu unmöglich, einzelne Eigenschaften unabhängig von anderen zu verändern. Bei einer Mischungsoptimierung muss im Einzelfall immer entschieden werden, welcher der gewünschten Eigenschaften die höchste Priorität zukommt. Anhand von Parameterstudien wird im vorliegenden Artikel verdeutlicht, wie es für bestimmte Anwendungen sinnvoll sein kann, die Verschlechterung einzelner Eigenschaften zu akzeptieren, wenn dadurch eine für den speziellen Einsatzfall essenzielle Eigenschaft verbessert werden kann. Die komplexen Wechselwirkungen der einzelnen Bestandteile fuhren dazu, dass auch scheinbar widersprüchliche Kombinationen von Zusatzmitteln im Einzelfall erforderlich werden können. Zur Anpassung der meisten Mörteleigenschaften gibt es verschiedene Möglichkeiten der Zielerreichung mit jeweils unterschiedlichen Nebeneffekten. Frisch- und Festmörteleigenschaften sind dabei gleichermaßen zu beachten. T2 - 2. Kolloquium "Erhaltung von Bauwerken" CY - Ostfildern/Stuttgart, Germany DA - 25.01.2011 KW - Betoninstandsetzung KW - Instandsetzungsmörtel KW - Modulare Systeme KW - Polymer cement mortar (PCC) KW - Sprayed polymer cement mortar (SPCC) PY - 2011 SN - 3-924813-87-6 SP - 213 EP - 221 AN - OPUS4-23218 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - Zum Einfluss der Menge und Modifikation des Fließmittels auf das Erstarren, die Wärmeentwicklung und die frühen Verformungen von Bindemittelleimen T2 - 18. Ibausil - Internationale Baustofftagung CY - Weimar, Germany DA - 2012-09-12 KW - Polycarboxylatether KW - Fließmittel KW - Erstarren KW - Hydratationswärme KW - Schwinden PY - 2012 SN - 978-3-00-034075-8 VL - 2 IS - 3.07 SP - 2-0392 - 2-0399 AN - OPUS4-26543 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Fontana, Patrick A1 - Maier, Bärbel T1 - Vermeidung stofflicher Probleme bei der Wärmebehandlung von Beton T2 - BMO-Fachtagung "Beton für alle Wetter", BAM CY - Berlin, Germany DA - 2012-11-22 PY - 2012 AN - OPUS4-27110 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Fontana, Patrick A1 - Maier, Bärbel T1 - Vermeidung stofflicher Probleme bei der Wärmebehandlung von Beton T2 - Fachtagung 'Beton für alle Wetter' CY - Berlin, Germany DA - 2012-11-22 PY - 2012 SP - 109 EP - 116 AN - OPUS4-27175 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Schießl, P. A1 - Meng, Birgit A1 - Rößler, G. A1 - Schröder, P. A1 - Schwamborn, B. A1 - Spengler, A. A1 - Wallner, B. ED - Zilch, K. ED - Diederichs, C.J. ED - Katzenbach, R. ED - Beckmann, K. J. T1 - Konstruktiver Ingenieurbau und Hochbau KW - Baustoffe KW - Beton KW - Bindemittel KW - Zement PY - 2012 SN - 978-3-642-14449-3 IS - Kap. 3.1 SP - 966 EP - 1038 PB - Springer ET - 2. Aufl. AN - OPUS4-25844 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten A1 - Meng, Birgit ED - Roussel, N. ED - Bessaies-Bey, H. T1 - A simple test method to assess the influence of PCEs on the rheology of flowable cementitious systems N2 - Today’s superplasticizers for self-compacting concrete and high Performance cementitious materials are very versatile. Typically superplasticizers are composed of a polycarboxylic backbone equipped with polyethylene oxide graft chains of variable length and grafting degree. The mode of operation of these admixtures is based on the steric repulsion of the particles upon adsorption. The adsorption is strongly depending upon the charge density of a superplasticizer and the time dependent Adsorption processes control the retention of the flow performance – an important issue particularly for ready-mix and construction site concrete. However, the properties of polycarboxylic superplasticizers typically remain a black box for users. The paper suggests a simple and rapid test method, which can be conducted without sophisticated equipment, to qualitatively distinguish between two types of superplasticizers based on the adsorption mechanism. Interpreting the results in the right way provides a powerful tool to choose the right admixture for individual time dependent flow specifications. T2 - 1st international RILEM conference on rheology and processing of construction materials and 7th RILEM conference on self-compacting concrete CY - Paris, France DA - 02.09.2013 KW - Adsorption KW - Polycarboxylate ether KW - Rheology KW - Slump flow PY - 2013 SN - 978-2-35158-137-7 IS - Chapter 2.1.1 SP - 1 EP - 8 AN - OPUS4-29929 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - The working mechanism of starch and diutan gum in cementitious and limestone dispersions in presence of polycarboxylate ether superplasticizers N2 - Polysaccharides provide high potential to be used as rheology modifying admixtures in mineral binder systems for the construction industry such as concrete or mortar. Since superplasticizers have become state of technology, today, concrete is more and more adjusted to flowable consistencies. This often goes along with the risk of segregation, which can be effectively avoided by adding stabilising agents supplementary to superplasticizers. Stabilising agents are typically based on polysaccharides such as cellulose, sphingan gum, or starch. Starch clearly distinguishes in its effect on rheology from other polysaccharides, mainly due to the strong influence of amylopectin on the dispersion and stabilisation of particles. Based on rheometric investigations on cementitious and limestone based dispersions with different volumetric water to solid ratios, the mode of operation of modified potato starch is explained in comparison to a sphingan gum. It is shown that the stabilising effect of starch in a coarsely dispersed system is mainly depending upon the water to solid ratio and that above a certain particle volume threshold starch mainly affects the dynamic yield stress of dispersions, while plastic viscosity is affected only to a minor degree. Sphingans operate more independent of the particle volume in a coarsely dispersed system and show significantly higher effect on the plastic viscosity than on the yield stress. In systems incorporating superplasticizers, influences of both stabilising agents on yield stress retreat into the background, while both observed polysaccharides maintain their effect on the plastic viscosity. KW - Cement KW - Limestone KW - Rheology KW - Stabilising agent KW - Coarsely dispersed systems KW - Diutan gum KW - Starch ether PY - 2013 U6 - https://doi.org/10.3933/ApplRheol-23-52903 SN - 1430-6395 SN - 0939-5059 VL - 23 IS - 5 SP - 52903-1 EP - 52903-12 PB - Kerschensteiner CY - Lappersdorf AN - OPUS4-29932 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pistol, Klaus A1 - Weise, Frank A1 - Meng, Birgit ED - Roussel, N. ED - Bessaies-Bey, H. T1 - High temperature behaviour of self-compacting concrete with limestone powder N2 - Although concrete in general is a non-combustible material, the fire resistance of concrete structures depends, to a large extent, on the mechanical material behaviour. Fire tests have shown that SCC is often susceptible to explosive spalling due to fire exposure, in a similar manner to HPC. But there are hardly any studies available that report properties of specimens at high temperatures. T2 - 7th RILEM International conference on self-compacting concrete and of the 1st RILEM international conference on rheology and processing of construction materials CY - Paris, France DA - 02.09.2013 KW - Fire resistance KW - Stress-strain-relation KW - Compressive strenght KW - Polypropylene fibres KW - Self-compacting concrete KW - Thermo mechanical behaviour KW - Fire safety design PY - 2013 SN - 978-2-35158-137-7 SN - 978-2-35158-138-4 SP - 221 EP - 228 PB - RILEM Publications CY - Bagneux, France AN - OPUS4-29985 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pirskawetz, Stephan A1 - Weise, Frank A1 - Meng, Birgit A1 - Rogge, Andreas T1 - Vom Baustoff zum sicheren Bauwerk: Einsatz der Schallemissionsanalyse in der Bauabteilung der BAM N2 - Seit 2006 wird die Schallemissionsanalyse (SEA) in der Abteilung 7 Bauwerkssicherheit der BAM genutzt, um Gefügeveränderungen in Betonen zu untersuchen. Dabei haben sich bis heute im Wesentlichen folgende vier Forschungsbereiche herauskristallisiert: Hydratation Während der Hydratation von Beton ist eine ausgeprägte Schallemissionsaktivität zu beobachten, anhand derer der Hydratationsverlauf nachvollzogen werden kann. Zur Aufklärung der Quellmechanismen der Schallemissionen besteht noch weiterer Forschungsbedarf. Des Weiteren kann mit Hilfe der SEA die frühe Rissbildung in Betonen, hervorgerufen durch autogenes oder plastisches Schwinden, analysiert werden. Alkali-Kieselsäure-Reaktion (AKR) Bei der AKR handelt es sich um eine Reaktion alkaliempfindlicher Gesteinskörnungen mit den Alkalien des Betons bzw. mit extern, z.B. durch Tausalze, zugeführten Alkalien. Dabei werden um die oder in der Gesteinskörnung quellfähige Gele gebildet, die zu einer völligen Zerstörung des Gefüges führen können. Mit der SEA können die Rissbildung detektiert und somit die Schädigungsphasen im Verlauf der AKR identifiziert werden. Brandverhalten Unter Brandeinwirkung platzt die Oberfläche gefügedichter Hochleistungsbetone explosionsartig ab. Um dies zu verhindern und somit den Feuerwiderstand von Bau-teilen aus Hochleistungsbeton zu erhöhen, werden dem Beton Polypropylenfasern beigemischt. Das Schmelzen der Fasern bei einer Temperaturerhöhung trägt zu einer erhöhten Mikrorissbildung bei, die einen Spannungsabbau ermöglicht. Die SEA konnte erfolgreich eingesetzt werden, um diesen Wirkmechanismus der Fasern nachzuweisen und weiter aufzuklären. Ermüdungsverhalten Durch die hohen zyklischen Lasten, für die Türme und Fundamente von Windkraft-anlagen ausgelegt werden müssen, gewinnen gesicherte Kenntnisse über das Ermüdungsverhalten von Betonen an Bedeutung. Mit der SEA ist es bei hochzyklischen Belastungsversuchen an Betonen möglich, den Schädigungsgrad im Verlauf der Beanspruchung zu bestimmen. Die Schallemissionsaktivität eignet sich als Kriterium, um die Versuche bei vorab definierten Schädigungsgraden zu unterbrechen und so Proben für weitergehende Untersuchungen zu gewinnen. Diese Ergebnisse sollen perspektivisch für Überwachungssysteme für Betonbauwerke unter zyklischer Beanspruchung genutzt werden. T2 - 19. Kolloquium Schallemission - Statusberichte zur Entwicklung und Anwendung der Schallemissionsanalyse CY - Augsburg, Germany DA - 12.09.2013 KW - Bauwerkssicherheit KW - Schallemissionsprüfung KW - Beton KW - Hydratation KW - Alkali-Kieselsäure-Reaktion KW - Brandverhalten KW - Ermüdungsverhalten PY - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-300290 SN - 978-3-940283-51-1 N1 - Serientitel: DGZfP-Berichtsband – Series title: DGZfP-Berichtsband IS - 142 SP - 1 EP - 12 (Beitrag 10) PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung CY - Berlin AN - OPUS4-30029 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram A1 - Sonebi, M. A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten A1 - Meng, Birgit ED - Diouri, A. ED - Khachani, N. ED - Alami Talbi, M. ED - Ait Brahim, L. ED - Bahi, L. T1 - Rheology modifying admixtures: The key to innovation in concrete technology - a general overview and implications for Africa N2 - Innovative admixture technology has significantly widened up the ränge of possibilities of concrete engineers. For many decades the water to cement ratio (w/c) was the major influencing factor for the performance of concrete. Due to the need to adjust a consistency, which still allowed reasonable workability, the w/c was typically significantly higher than technologically reasonable. Rheology modifying admixtures Support adjusting the concrete consistency largely independent of the w/c. It was only after the invention of the first superplasticizers that modern concrete technology significantly evolved in terms of flowability, strength, and durability, and only due to the steady evolution of the technology modern innovations, such as Self-Compacting Concrete, Ultra-High-Performance Concrete, or Engineered Cementitious Composites were made possible. Today’s superplasticizers are extremely versatile and can be adjusted to individual technological specifications. However, the other side of the coin of versatility is that cementitious Systems incorporating superplasticizers have become more sensitive against environmental influences, such as the environmental temperature, which may cause unwanted effects or demand for supplementary admixture use such as stabilizing admixtures. Hence, concrete mixture composition with admixtures demands for a high level of expertise and offen there is lack of awareness about the mode of Operation of rheology modifying admixtures among concrete technologists. The paper gives a comprehensive overview about rheology modifying admixtures such as superplasticizers or stabilizing agents, and how they can be used depending upon the application in the most favourable way. Based on experiences with the sub-Saharan African concreting boundary conditions, which exhibit many challenges in terms of environmental boundary conditions and construction site logistics, conclusions are finally drawn, how admixtures can be used in the most beneficial way to improve the concrete casting Situation. T2 - CMSS 2013 - International congress on materials & structural stability - Building up sustainable materials & constructions CY - Rabat, Morocco DA - 27.11.2013 KW - Rheology KW - Superplasticizers KW - Stabilising agents PY - 2013 SN - 978-9954-32-689-3 SP - 1 EP - 6 AN - OPUS4-30040 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - Interactions between PCE and different polysaccharides and influences on the early hydration of cement N2 - ln order to observe the influence of stabilising agents (STA) based on starch and diutan gum, rheometric experiments and setting tests were conducted on cement pastes with and without PCE superpiasticizers. The results show that with regard to yield stress both STAs show differing behaviours in Systems without PCE. In presence of PCE, yield stress infiuences of the STAs retreat into the background. The Vicat results exhibit that STAs can reduce the retard ing effect of PCE. T2 - 1st International conference on the chemistry of construction materials CY - Berlin, Germany DA - 07.10.2013 PY - 2013 SN - 978-3-936028-75-1 N1 - Serientitel: GDCh-Monographien – Series title: GDCh-Monographien VL - 46 SP - 49 EP - 52 AN - OPUS4-30045 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weise, Frank A1 - von Werder, Julia A1 - Manninger, Tanja A1 - Maier, Bärbel A1 - Fladt, Matthias A1 - Simon, Sebastian A1 - Gardei, Andre A1 - Höhnel, Desirée A1 - Pirskawetz, Stephan A1 - Meng, Birgit T1 - A multiscale and multimethod approach to assess and mitigate concrete damage due to alkali-silica reaction N2 - Alkali-silica reaction (ASR) is a chemical reaction within concrete which can lead over time to cracking and spalling. Due to the complexity of the problem, it still causes damage to concrete constructions worldwide. The publication aims to illustrate the interdisciplinary research of the German Federal Institute for Materials Research and Testing (BAM) within the last 20 years, considering all aspects of ASR topics from the macro to the micro level. First, methods for characterization and assessment of ASR risks and reaction products used at BAM are explained and classified in the international context. Subsequently the added value of the research approach by combining different, preferably nondestructive, methods across all scales is explained using specific examples from a variety of research projects. Aspects covered range from the development of new test-setups to assess aggregate reactivity, to analysis of microstructure and reaction products using microscopical, spectroscopical and X-ray methods, to the development of a testing methodology for existing concrete pavements including in-depth analysis of the visual damage indicator and the de-icing salt input using innovative testing techniques. Finally, research regarding a novel avoidance strategy that makes use of internal hydrophobization of the concrete mix is presented. KW - Mitigation strategies KW - Concrete KW - Damage analysis KW - Alkali silica reaction KW - Road pavement KW - Accelerated testing KW - Non-destructive testing KW - Microstructure PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2022052515100075090235 SN - 1527-2648 VL - 24 IS - 6 SP - 1 EP - 36 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54951 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krütt, Enno A1 - Pirskawetz, Stephan A1 - Wallau, Wilma A1 - Meng, Birgit T1 - Development of an automated 60 °C Concrete Prism Test N2 - ln most of the ASR-test procedures, the expansion of concrete or mortar specimens is used as an indicator to assess the ASR-potential of an aggregate or a specific concrete mix. For these tests, the specimens are stored in an ASR-provoking environment, where the reaction is accelerated by elevated temperature and humidity. To measure the length change, the storage must be interrupted for at least a few minutes. Düring the 60 °C Concrete Prism Test (60 °C-CPT), the specimens are cooled down to 20 °C for 24 hours, to ensure the same hygrothermal conditions for every measurement. This limits the number of measurements during the test period and may lead to additional effects, that probably influence the expansion development. With a recently developed device, it is possible to continuously monitor the expansion ofprisms without interrupting the ASR-provoking storage. Due to the dense database of this automated test, the results can contribute to a better understanding of the ASR-process. This study compares results of the automated and conventional 60 °C-CPT. Tests of different aggregates showed, that the results of the automated and conventional test are consistent, but the expansions during the conventional test are generally higher. Preliminary results led to the conclusion, that the cooling for the measurements leads to additional expansions. Therefore, a modified threshold should be discussed for the automated 60 °C-CPT. T2 - 16th International Conference on Alkali-Aggregate Reaction in Concrete CY - Lisboa, Portugal DA - 31.05.2022 KW - 60 °C-CPT KW - ASR expansion monitoring KW - Automated testing PY - 2021 SN - 978-972-49-2315-4 VL - 1 SP - 789 EP - 799 AN - OPUS4-54553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Gehlen, C. A1 - Kränkel, T. A1 - Meng, Birgit A1 - Osterminski, K. A1 - Meyer, F. A1 - Schröder, P. ED - Zilch, K. T1 - Baustoffe im Betonbau N2 - In dem Kap. „Baustoffe im Betonbau“ werden zunächst die Baustoffe vorgestellt, die für die Herstellung von Stahlbeton- und Spannbetonbauwerken erforderlich sind (im Wesentlichen Beton, Betonstahl und Spannstahl). Herstellungsbedingte, typische Eigenschaftsprofile der Baustoffe werden aufgezeigt und ein Bezug zu entsprechenden Anwendungsgebieten hergestellt. KW - Betontechnik KW - Bindemittel KW - Betonstahl KW - Spannstahl KW - Herstellungsprozesse KW - Eigenschaften KW - Anwendungsbeispiele PY - 2019 SN - 978-3-658-21749-5 U6 - https://doi.org/10.1007/978-3-658-21749-5_15-1 SP - 1 EP - 63 PB - Springer Fachmedien Wiesbaden GmbH AN - OPUS4-54173 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - von Werder, Julia A1 - Simon, Sebastian A1 - Meng, Birgit T1 - Internal sulfate resistance of concrete N2 - If the amount of sulfate within the mix design for concrete is not balanced, ettringite formation which first controls solidification continues while the concrete is hardening. Ettringite forms by reaction of sulfate contained in the cement or in some admixture with calcium aluminate (C3A) as cement component. The “late primary ettringite formation” promotes an increase in volume within the hardened concrete leading to cracks. To analyze the effect of substituting part of ordinary Portland cement (OPC) by a treated brown coal fly ash mortar bars were tested according to ASTM C452. This test method was originally developed to extrapolate from the internal to external sulfate attack and is based on the idea that by testing a concrete mixture containing sulfate the process of deterioration is accelerated because it does not have to diffuse into the concrete before reaction first. In addition to the samples prescribed in ASTM C452 further samples in the size of the German SVA procedure were tested also designed for accessing the external sulfate resistance. The results show that while the replacement of 25 % of cement by brown coal fly ash leads to length changes around the limit defined by ASTM, the substitution of 50 % cement exceeded the limit by a multiple. The progress of expansion is the very similar for the two geometries tested. In-situ XRD measurements confirmed that while for pastes made of OPC the formation of ettringite is completed after 20 hours, this is not true for the mixtures containing the brown coal fly ash. In a different study the effect of hydrothermal treatment on the phase composition of ultra-high-performance concrete was analyzed. The results show that the sulfate and aluminate resulting from the decomposition of ettringite are bound into new phases. If this binding is permanent this might allow the larger use of sulfate bearing raw materials. T2 - EuroCoalAsh 2021 Conference CY - Online meeting DA - 02.11.2021 KW - Brown coal fly ash KW - Ettringite KW - Internal sulfate resistance KW - Test methods KW - In-situ XRD KW - Hydrothermal treatment PY - 2021 SP - 131 EP - 137 CY - Thessaloniki AN - OPUS4-54133 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schraut, Katharina A1 - Adamczyk, Burkart A1 - Adam, Christian A1 - Stephan, D. A1 - Meng, Birgit A1 - Simon, Sebastian A1 - von Werder, Julia T1 - Synthesis and characterisation of alites from reduced basic oxygen furnace slags N2 - Basic oxygen furnace slags (BOFS) are by-products of the steelmaking process. Several researchers have studied the production of Portland cement clinker and metallic iron from BOFS via a reductive treatment. In this study, we applied a carbothermal reduction of BOFS in a technical-scale electric arc furnace and characterised the clinker-like products. Those clinker-like non-metallic products (NMPs) had a chemical and mineralogical composition comparable to clinker for ordinary Portland cement (OPC) and contained large elongated alite crystals as major component. The pure NMPs reacted more slowly and achieved a lower degree of hydration compared with commercial OPC. If the reactivity of the products can be further increased by employing specific adaptations, it can be used as a full clinker substitute for OPC. Nevertheless, it is also an option to use the material without further modifications as a cement component or concrete addition, which contributes to the strength development in both cases. KW - BOFS KW - Hydration products KW - Thermal analysis KW - X-ray diffraction PY - 2021 U6 - https://doi.org/10.1016/j.cemconres.2021.106518 SN - 0008-8846 VL - 147 SP - 6518 PB - Elsevier Ltd. AN - OPUS4-52939 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bahlmann, Stefanie A1 - Rübner, Katrin A1 - Meng, Birgit T1 - Untersuchungen zur Verwertung industrieller Reststoffe als Ersatz von Primärrohstoffen in Mörtel und Beton N2 - Um den Abbau primärer Rohstoffe zu reduzieren, wurden deponierte oder niederwertig eingesetzte industrielle Reststoffe hinsichtlich einer höherwertigen Verwendung im Betonbau untersucht. Zur Bewertung des Einsatzpotentials als Zementbestandteil oder Betonzusatzstoff erfolgte zunächst eine chemisch-mineralogische und betontechnologische Charakterisierung der Materialien. Reststoffe, die die normativen Anforderungen hinsichtlich der Zementzusammensetzung erfüllen, wurden anschließend zu verschiedenen Anteilen als Zementsubstitut in Mörtel eingesetzt. In vergleichenden Untersuchungen erfolgte die Ermittlung der Frisch- und Festmörteleigenschaften. Kalorimetrische Untersuchungen sollten die Auswirkungen der Reststoffe auf die Zementhydratation zeigen. Ausgewählte Untersuchungsergebnisse an Reststoffen aus der Industrieabwasseraufbereitung, dem Altpapierrecycling, der Biomasseverbrennung und der Metallurgie werden vorgestellt. T2 - 17. Internationale Baustofftagung IBAUSIL 2009 CY - Weimar, Germany DA - 23.09.2009 KW - Industrieabwasseraufbereitung KW - Altpapierrecycling KW - Biomasseverbrennung KW - Metallurgie PY - 2009 AN - OPUS4-36516 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weise, Frank A1 - Meng, Birgit A1 - Pirskawetz, Stephan A1 - Voland, K. T1 - Influence of simultaneous cyclic loading and external alkali supply on the alkali-silica reaction in concrete pavements N2 - In recent years the German motorway network has seen an increase in the occurrence of damage to concrete road surfaces which can be attributed to the alkali-silica reaction (ASR). In view of the often drastically reduced life expectancy of road surfaces due to ASR, research activity in this field has notably increased. Alongside preventative measures in concrete technology, the main research focus up to now has been the development of performance-oriented testing procedures for ASR prevention. This included more specifically the accelerated simulation of climatic effects and external alkali penetration on road surfaces. The effects of mechanical pre-damage resulting from cyclic traffic loading and climatic impact had previously not been taken into consideration. Since 2011, the five-partner research group 1498 sponsored by the German Research Foundation (DFG) has been pursuing research on how simultaneous cyclic loading and external alkali penetration impacts destructive ASR in road surface concretes. The depiction of the myriad degradation and transport processes necessary for an understanding of these effects requires close interaction between experiments and their multi-scale modelling. This paper aims to focus on the aforementioned experiments by means of innovative testing techniques. The research is founded on a series of cyclic fatigue tests performed on large-format beams, both with and without previous application of a sodium chloride (NaCl) solution, with simultaneous tracking of crack development. Subsequently, smaller test specimens were extracted from the pre-damaged beams for further experiments. These included the spatial visualization and quantification of fatigue-induced cracks using micro X-ray 3D-computed tomography (3D-CT). Additionally, the effects of fatigue-induced cracks on alkali transport were investigated using Laser-Induced Breakdown Spectroscopy (LIBS). Subsequent storage of the small-format test specimens, with and without cyclic pre-damage, in an ASR-conducive environment then provided initial findings on the influence of fatigue-induced predamage on the ASR. T2 - 15th International Conference on Alkali-Aggregate reaction (ICAAR 2016) CY - Sao Paulo, Brazil DA - 03.07.2016 KW - concrete pavements KW - alkali-silica-reaction KW - fatigue KW - damage monitoring PY - 2016 SP - Paper 191 AN - OPUS4-37142 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Werner, Daniel A1 - Meng, Birgit A1 - Weise, Frank T1 - Influence of aggregate size on the damage potential of alkali-silica reaction N2 - The susceptibility of different aggregate types used in concrete to ASR is strongly associated with their petrography. The aim of this study is to assess the influence of the aggregate size on the ASR potential, in particular applied to the sand fractions in the size range of 0.125-4 mm. The investigation concept is based on the hypothesis that at a specific particle size reactive aggregates could change their characteristic influence in mitigating ASR instead of promoting it. For the study of the size dependent behaviour mortars are prepared, considering aggregates of different reactivity, including very reactive, slow-late and quasi non-reactive types. The analysis is based on a stepwise substitution concept, in which mortars with a constant overall grain size distribution are compared, while only one size fraction of the non-reactive base aggregate is substituted by a reactive aggregate type of this specific size fraction. For the expansion experiments an accelerated mortar bar test (80°C, immersed in NaOH solution) was applied. The results show that the slow-late reactive greywacke yielded a strong reduction of the expansion below an aggregate size in the range of 0.5-1 mm. On the other side with the very reactive borosilicate glass, the expansions increased steadily with decreasing size. To validate if the acquired expansions were caused by ASR, thin sections were analysed. Mainly, higher expansion values were consistent with extensively more amounts of ASR indicators. T2 - 15th International Conference on Alkali-Aggregate Reaction (ICAAR 2016) CY - Sao Paulo, Brazil DA - 03.07.2016 KW - alkali-silica-reaction KW - building materials KW - concrete KW - durability PY - 2016 SP - Paper 194 AN - OPUS4-37143 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Selleng, Christian A1 - Meng, Birgit A1 - Fontana, Patrick ED - Fehling, E. ED - Middendorf, B. ED - Thiemicke, J. T1 - Phase composition and strength of thermally treated UHPC N2 - Thermal treatment improves the excellent properties of UHPC. Recent studies have shown that an increase in compressive strength of more than 30 % is possible. However, the accurate conditions of thermal treatment for a maximal strength are considered as yet undetermined. A multitude of parameters can be varied: temperature, pressure, water saturation, and duration of the process steps. These parameters influence the phase development and in consequence the macroscopic properties of UHPC. The primary objective of the presented study was the optimisation of the conditions for thermal treatment, concerning compressive strength. It focuses on pre-storage time and duration of the treatment at defined temperatures and pressures (90 °C and 185 °C/1.1MPa). As expected, experimental results showed a fundamental change of phase composition in hydrothermally treated UHPC in comparison to standard cured UHPC: Ettringite decomposes at higher temperatures and is absent after thermal treatment; the amount of portlandite and clinker phases decreases. The change of phase composition is accompanied by increased compressive strength. Experimental studies of calcium-silicate-systems at hydrothermal conditions predict the formation of the crystalline C-S-H phase tobermorite. In fact, this is a typical phase occurring in other hydrothermally treated calcium-silicate-systems like Autoclaved Aerated Concrete (AAC). Commonly, high strength is attributed to the presence of tobermorite; however, in the presented study tobermorite was not detected in the hydrothermally treated UHPC. Therefore, tobermorite cannot be responsible for the increased strength of hydrothermally treated UHPC. In conclusion the development of phases and strength of UHPC at hydrothermal conditions differs fundamentally from AAC and the experimental studies with water saturation. Results of these systems cannot be transferred to UHPC. In thermally treated UHPC, the hydration of clinker is enhanced and the puzzolanic reaction is intensified. Hence, more C-S-H is formed that fills pores and cracks, leading to a denser structure and finally to higher strength. T2 - 4th International Symposium on Ultra-High Performance Concrete and High Performance Materials (HiPerMat) CY - Kassel, Germany DA - 09.03.2016 KW - Ultra-high performance concrete KW - Thermal treatment KW - Compressive strength KW - Tobermorite KW - C-S-H KW - Building Materials PY - 2016 SN - 978-3-7376-0094-1 VL - 27 SP - 7 EP - 8 PB - kassel university press GmbH CY - Kassel AN - OPUS4-36872 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Simon, Sebastian A1 - Meng, Birgit A1 - Selleng, Christian T1 - A new sample holder for fast xrd investigation on UHPC N2 - A new sample holder is described in this poster. It was developed in BAM for fast XRD investigation on UHPC (ultra high performance concrete). Results measuring solid, i.e. not pulverized, samples are shown. T2 - GeoBerlin 2015 CY - Berlin, Germany DA - 04.10.2015 KW - Building Materials KW - UHPC KW - X-ray diffractometry PY - 2015 AN - OPUS4-36949 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pistol, Klaus A1 - Weise, Frank A1 - Meng, Birgit A1 - Diederichs, U. T1 - Polypropylene fibres and micro cracking in fire exposed concrete N2 - Though, concrete in general is a non-combustible building material, modern High Performance Concrete (HPC) is very susceptible to violent explosive spalling during a fire attack. This requires protective measures for fire safety design of concrete structures. The current most worthwhile method to prevent explosive spalling is the addition of monofilament Polypropylene fibres (PP-fibres). However, since it has become common knowledge that PP-fibres are suitable for fire safety design, a variety of theories concerning the mode of action of PP-fibres have been suggested. The present article summarizes the most important hypothesis and presents an innovative method for the analysis of micro structural processes in heated specimens. The results show that due to the thermal decomposition of PP-fibres capillary channels are created. Simultaneously, a netlike micro crack formation occurs, which connects these capillary channels. This enables the relief of internal stresses (mechanical effect) and the formation of a permeable transport system for the escaping water vapour (permeation effect). KW - Concrete KW - Fire Spalling KW - Micro-Crack KW - Polypropylene Fibres PY - 2014 U6 - https://doi.org/10.4028/www.scientific.net/AMR.897.284 SN - 1022-6680 SN - 1662-8985 VL - 897 SP - 284 EP - 289 PB - Trans Tech Publ. CY - Zurich AN - OPUS4-30383 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stroh, Julia A1 - Schlegel, Moritz-Caspar A1 - Irassar, E.F. A1 - Meng, Birgit A1 - Emmerling, Franziska T1 - Applying high resolution SyXRD analysis on sulfate attacked concrete field samples N2 - High resolution synchrotron X-ray diffraction (SyXRD) was applied for a microstructural profile analysis of concrete deterioration after sulfate attack. The cement matrices consist of ordinary Portland cement and different amounts of supplementary cementitious materials, such as fly ash, natural pozzolana and granulated blast furnace slag. The changes of the phase composition were determined along the direction of sulfate ingress. This approach allows the identification of reaction fronts and zones of different phase compositions and conclusions about the mechanisms of sulfate attack. Two reaction fronts were localized in the initial 4 mm from the sample surface. The mechanism of deterioration caused by the exposition in the sulfate-bearing soil is discussed. SyXRD is shown to be a reliable method for investigation of cementitious materials with aggregates embedded in natural environments. KW - X-ray diffraction (B) KW - High resolution KW - Degradation (C) KW - Sulfate attack (C) KW - Concrete (E) PY - 2014 U6 - https://doi.org/10.1016/j.cemconres.2014.07.015 SN - 0008-8846 SN - 1873-3948 VL - 66 SP - 19 EP - 26 PB - Pergamon Press CY - New York, NY AN - OPUS4-31253 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - Influences of superplasticizer modification and mixture composition on the performance of self-compacting concrete at varied ambient temperatures N2 - The fresh behaviour of self-compacting concrete (SCC) at varying temperatures differs from that of normal vibrated concrete. This is because the rheology of SCC depends not only on degree of cement hydration, but also on the adsorption of superplasticizers – mostly polycarboxylate based polymers (PCE) -, which is affected by the time and hydration progress. Due to the variety of PCEs and mixture compositions for SCC a prediction of the rheology at varying temperatures is complicated. The charge densities of PCEs as well as the water to solid ratio in the paste are identified to be the main decisive parameters for robust fresh concrete properties. Rheometric concrete investigations with different SCC mixture compositions and varied anionic charge densities of the PCE were conducted. SCC which is rich in powder components showed robust performance at low temperatures while SCC with low powder content was favourable at high temperatures. High charge density PCE pointed out to be very robust at low temperatures but at high temperatures it significantly reduced the flow retention. Low charge density PCE could not generate self-compacting properties at low temperatures but retained the flow performance over sufficiently long time. Based on considerations about particle interactions and adsorption mechanisms of PCEs, the relevant processes are explained and options for the development of robust mixture compositions for individual temperature ranges are itemised. KW - Polycarboxylate ether KW - Temperature KW - Rheology KW - Mixture composition KW - Self-compacting concrete PY - 2014 U6 - https://doi.org/10.1016/j.cemconcomp.2013.12.004 SN - 0958-9465 SN - 1873-393X VL - 49 SP - 111 EP - 126 PB - Elsevier CY - Barking, Essex AN - OPUS4-30552 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Sonebi, M. A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - Rheology modifying admixtures: The key to innovation in concrete technology - a general overview and implications for Africa N2 - Innovative admixture technology has significantly widened up the ränge of possibilities of concrete engineers. For many decades the water to cement ratio (w/c) was the major influencing factor for the performance of concrete. Due to the need to adjust a consistency, which still allowed reasonable workability, the w/c was typically significantly higher than technologically reasonable. Rheology modifying admixtures Support adjusting the concrete consistency largely independent of the w/c. It was only after the invention of the first superplasticizers that modern concrete technology significantly evolved in terms of flowability, strength, and durability, and only due to the steady evolution of the technology modern innovations, such as Self-Compacting Concrete, Ultra-High-Performance Concrete, or Engineered Cementitious Composites were made possible. Today’s superplasticizers are extremely versatile and can be adjusted to individual technologicalspecifications. However, the other side of the coin of versatility is that cementitious Systems incorporating superplasticizers have become more sensitive against environmental influences, such as the environmental temperature, which may cause unwanted effects or demand for supplementary admixture use such as stabilizing admixtures. Hence, concrete mixture composition with admixtures demands for a high level of expertise and offen there is lack of awareness about the mode of Operation of rheology modifying admixtures among concrete technologists. The paper gives a comprehensive overview about rheology modifying admixtures such as superplasticizers or stabilizing agents, and how they can be used depending upon the application in the most favourable way. Based on experiences with the sub-Saharan African concreting boundary conditions, which exhibit many challenges in terms of environmental boundary conditions and construction site logistics, conclusions are finally drawn, how admixtures can be used in the most beneficial way to improve the concrete casting Situation. KW - Rheology KW - Admixtures KW - Concrete KW - Superplasticizers KW - Polycarboxylate ether KW - Viscosity modifying agents PY - 2013 SN - 2224-3224 SN - 2225-0956 VL - 5 SP - 115 EP - 120 PB - International Institute for Conservation of Historic and Artistic Works CY - New York, NY, USA AN - OPUS4-30948 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Fontana, Patrick A1 - Pirskawetz, Stephan A1 - Weise, Frank A1 - Meng, Birgit ED - Nothnagel, R. ED - Twelmeier, H. T1 - Zwangsinduzierte Rissbildung in Hochleistungsbeton durch autogenes Schwinden N2 - In diesem Beitrag werden Untersuchungsergebnisse vorgestellt, die den Einfluss von Mikrosilica auf die Selbstaustrocknung und das damit verbundene autogene Schwinden der Bindemittelmatrix von Hochleistungsbetonen beschreiben. Die dadurch hervorgerufenen Schädigungsprozesse wurden mit Hilfe von zerstörungsfreien Prüfmethoden verfolgt. Dabei zeigte sich, dass eine durch äußeren Zwang bedingte Mikrorissbildung durch Schallemissionsanalyse detektiert werden kann. KW - Beton KW - Verformung KW - Rissbildung KW - Zusatzstoffe PY - 2013 SN - 978-3-642-29573-7 U6 - https://doi.org/10.1007/978-3-642-29573-7_34 SP - 343 EP - 350 PB - Springer CY - Berlin Heidelberg AN - OPUS4-31758 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Meschke, Günther T1 - Ausmaß von Vorschädigungen, Transportprozesse in vorgeschädigtem Betongefüge T2 - AKR unter kombinierter Einwirkung CY - Weimar, Deutschland DA - 2014-10-21 PY - 2014 AN - OPUS4-31705 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Eichhorn, Michael A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - Performance-Verbesserung bei Betonwerksteinen durch multi-funktionelle Nano-Additive T2 - 17. Internatiole Baustofftagung "ibausil" CY - Weimar, Germany DA - 2009-09-23 PY - 2009 AN - OPUS4-19556 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Huismann, Sven A1 - Weise, Frank A1 - Meng, Birgit A1 - Schneider, U. ED - Kodur, V. ED - Franssen, J.-M. T1 - Influence of polypropylene fibres on the thermal strain of high strength concrete at high temperatures T2 - 6th International conference "Structures in fire" CY - East Lansing, Michigan, USA DA - 2010-06-02 KW - High performance concrete KW - High temperatures KW - Polypropylene fibres KW - Thermal strain KW - Acoustic emission KW - Ultrasound PY - 2010 SN - 978-1-60595-027-3 SP - 719 EP - 726 PB - DEStech Publications, Inc. CY - Lancaster, PA, USA AN - OPUS4-21563 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Urs A1 - Bürgisser, Philip A1 - Weise, Frank A1 - Meng, Birgit ED - Castro-Borges, P. ED - Moreno, E.I. ED - Sakai, K. ED - Gjorv, O.E. ED - Banthia, N. T1 - The natural pozzolana 'Rhenish trass' and its effect on ASR in concrete T2 - CONSEC’10 - 6th International conference on concrete under severe conditions - Environment and loading CY - Mérida, Yucatán, México DA - 2010-06-07 KW - AKR KW - Beton KW - Natürliche Pozzolane PY - 2010 SN - 978-0-415-59316-8 SP - 313 EP - 320 PB - Taylor & Francis AN - OPUS4-21969 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Fontana, Patrick A1 - Lehmann, Christian A1 - Müller, Urs A1 - Meng, Birgit ED - Brameshuber, W. T1 - Reactivity of mineral additions in autoclaved UHPC T2 - International Conference on Material Science and 64th RILEM Annual week CY - Aachen, Germany DA - 2010-09-06 KW - UHPC KW - Autoklavierung KW - Mikrostruktur KW - Festigkeit KW - Phasenzusammensetzung KW - Forschung und Entwicklung PY - 2010 SN - 978-2-35158-110-0 VL - III IS - PRO 77 SP - 69 EP - 77 PB - RILEM Publications AN - OPUS4-21970 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten A1 - Meng, Birgit A1 - Brouwers, H.J.H. ED - Aguiar, J. B. ED - Jalali, S. ED - Camoes, A. ED - Ferreira, R.M. T1 - Influence of ambient temperature conditions on the effect of stabilising polymers in cementitious building materials T2 - 13th International Congress on polymers in concrete - ICPIC 2010 CY - Funchal-Madeira, Portugal DA - 2010-02-11 KW - Stabilising agent KW - Polycarboxylate ether KW - Polysaccharides KW - Starch ether KW - Biopolymers KW - Rheology KW - Setting PY - 2010 SN - 978-972-99179-4-3 SP - 241 EP - 248 CY - Funchal-Madeira, Portugal AN - OPUS4-21971 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Herbst, Tristan A1 - Hauer, B. A1 - Rübner, Katrin A1 - Meng, Birgit T1 - Einsatzpotentzial und nachhaltige Verwertung von Hausmüllverbrennungsaschen als Gesteinskörnungen im Beton T2 - GDCh-Fachtagung Bauchemie 2009 CY - Freiberg, Deutschland DA - 2009-10-08 KW - Sekundärrohstoffe KW - Müllverbrennungsaschen KW - Sekundäre Gesteinskörnung PY - 2009 SN - 978-3-936028-61-4 VL - 41 SP - 237 EP - 240 AN - OPUS4-22951 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Herbst, Tristan A1 - Hauer, B. A1 - Rübner, Katrin A1 - Meng, Birgit ED - Teipel, U. T1 - Wege zur Bewertung der Einsatzmöglichkeit sekundärer Gesteinskörnungen in Beton T2 - Symposium Rohstoffeffizienz und Rohstoffinnovationen CY - Nürnberg, Deutschland DA - 2010-02-04 KW - Gesteinskörnung KW - Beton KW - Nachhaltigkeit KW - Bewertung KW - Einsatzpotenzial PY - 2010 SN - 978-3-8396-0097-9 SP - 171 EP - 191 PB - Fraunhofer IRB Verl. AN - OPUS4-22952 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Vasilic, Ksenija A1 - Meng, Birgit A1 - Kühne, Hans-Carsten A1 - Roussel, Nicolas T1 - Computational modelling of scc flow: reinforcement network modelled as a porous medium T2 - Rheo-Iceland 2009 3rd RILEM International Symposium on Rheology of Cement Suspensions Like Fresh Concrete CY - Reykjavik, Iceland DA - 2009-08-19 PY - 2009 AN - OPUS4-19403 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Jakubcová, Petra A1 - Schnell, A. A1 - Rübner, Katrin A1 - Müller, A. A1 - Meng, Birgit T1 - Nutzung von Bau- und Abbruchabfällen zur Herstellung von Recyclinggranulaten T2 - Tagung Bauchemie der GDCh-Fachgruppe Bauchemie 2010 CY - Dortmund, Deutschland DA - 2010-10-07 KW - Sekundärrohstoffe KW - Sekundäre Gesteinskörnung KW - Recycling PY - 2010 SN - 978-3-936028-65-2 VL - 42 SP - 129 EP - 136 AN - OPUS4-22444 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Herbst, Tristan A1 - Rübner, Katrin A1 - Meng, Birgit ED - Teipel, U. ED - Schmidt, R. T1 - Ganzheitliche Eignungsbewertung potenzieller Recyclingbereiche für Mauerwerksbruch N2 - Unsere Industriegesellschaft ist auf den ständigen Abbau und Verbrauch von Rohstoffen und Energie angewiesen. Der Bausektor zählt dabei zu den größten Verursachern von Stoffströmen in Deutschland. Zum einen ist das Bauen mit einem hohen Bedarf an materiellen und energetischen Ressourcen sowie finanziellen Aufwendungen verbunden. Zum anderen sind nahezu 50 % des deutschen Abfallaufkommens dem Bausektor zuzurechnen, Die Beschränktheit natürlicher Ressourcen, die zunehmenden negativen Umweltauswirkungen sowie die Verteuerung und Verknappung von Deponieraum führten in den letzten Jahren zu einem Umdenken in der Bau- und Abfallwirtschaft hin zu einer Kreislaufwirtschaft. Im Sinne einer nachhaltigen Kreislaufwirtschaft sind die im Bausektor anfallenden Restmassen zukünftig möglichst einem Recycling zuzuführen. Bei der Wahl der geeigneten Recyclingoption spielen technische, ökologische und ökonomische Fragestellungen eine Rolle. Für den Bereich Mauerwerksrecycling existiert bisher keine umfassende Methodik zur ganzheitlichen Eignungsbewertung (Technik, Ökologie, Ökonomie) mit einem vertretbaren Arbeitsaufwand. Grundlegende strukturierte und strukturierende Informationen für das Recycling von Mauerwerksbruch fehlen bislang. Aus diesem Grunde wird derzeit mit dem Ziel eines möglichst hochwertigen Mauerwerksrecyclings eine umfassende und praxisorientierte Methodik entwickelt. Diese Methodik soll eine ganzheitliche Eignungsbewertung unterschiedlicher potenzieller Recyclingbereiche für Mauerwerksbruch ermöglichen. Im vorliegenden Beitrag werden erste Ansätze dieser Bewertungsmethode vorgestellt. T2 - 2. Symposium "Rohstoffeffizienz und Rohstoffinnovationen" CY - Nürnberg, Germany DA - 10.02.2011 PY - 2011 SN - 978-3-8396-0222-5 VL - 2 SP - 153 EP - 165 PB - Fraunhofer Verlag AN - OPUS4-23255 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - Correlation between setting, heat evolution, and deformations of cementitious binder systems depending on type and amount of superplasticizer N2 - Today polycarboxylate ether based superplasticizer (PCE) is commonly used in concrete technology when high flow properties and water reduction are specified. The ionic strength of the polymers’ backbones determines the adsorption behaviour of polymers on clinker and early hydration products. The amount of required polymers for specified flow properties and the performance over the time of casting is thus determined by the molecular structure of the superplasticizer. The time depending consumption of polycarboxylate ether polymers strongly affects the reaction of aluminates and sulphate ions as well as the hydration process in general. Hence, the choice of polymers for particular flow properties greatly affects the very early properties of cementitious materials such as setting, heat evolution and autogenous deformations. In order to better understand how PCEs influence the early properties, mixes from cement, limestone filler, viscosity modifying agent and water were varied with a high and a low charge density superplasticizer in differing amounts. Results are presented from measurements with an automatic Vicat device, an isothermal heat flow calorimeter, and shrinkage cones. Tests were conducted at 5, 20, and 30 °C. It is shown that in presence of PCE the final set correlates well with the inflexion point of the heat flow curve, which emphasises the interrelation between C-S-H formation and setting. No such clear correlation can be found for the initial set, which is attributed to the fact that the initial set is rather a rheological than a structural phenomenon, so that other effects overlap with C-S-H formation. The results demonstrate that for a given polymer concentration low charge density polymers yield earlier setting than high charge polymers. However, this influence is overridden by the influence of the total amount of polymers in a cementitious system. Since PCE is typically added according to rheological specifications, and low charge PCE typically requires higher amounts of polymers than high charge PCE for comparable flow performance, low charge PCE retards setting more than high charge PCE. The paper furthermore points out that there is no significant influence of the polymer type or amount on the early deformations. Since type and amount strongly affect the hydration, it is demonstrated that early setting causes higher strain after the final set. It is hence concluded that higher PCE solid contents reduce the risk of early cracks that occur at time of setting, when a solid structure has already been formed but without resistance against cracks yet. T2 - 13th International congress on the chemistry of cement CY - Madrid, Spain DA - 03.07.2011 KW - Polycarboxylate superplasticizer KW - Setting KW - Heat evolution KW - Autogenous deformation KW - Self-compacting concrete KW - Calorimetry PY - 2011 SN - 978-84-7292-400-0 SP - 384 EP - 391 AN - OPUS4-24097 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ramge, Peter A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - Properties of repair mortars - potentials and risks of a tailor-made mixture proportioning N2 - Despite the numerous possibilities to influence the properties of repair mortars by modifications of the mixture proportioning, it is almost impossible to change an individual property without influencing other mortar properties. When optimising a mixture, it has to be decided for each individual case, which of the mortar properties needs to be treated with the highest priority. Most properties can be altered by several different measures, which may vary in effectiveness, side effects and cost efficiency. As the prevention of shrinkage induced constraining cracks is crucial for the durability and Service life of a concrete repair task, in the presented paper special attention is paid to the influences on the mortar’s shrinkage behaviour. On the basis of parameter studies it is shown, how it may be beneficial in certain cases to accept the worsening of some general properties if by this measure another property, which is essential for the individual application task, can be enhanced significantly. In general a tailor-made approach for the mixture proportioning seems beneficial but due to the complexity of the constituents’ interactions in repair mortars, it bears a high risk of unexpected malfunctions. T2 - Concrete-Workshop 'Performance-based specifications for concrete' CY - Leipzig, Germany DA - 14.06.2011 KW - Repair mortar KW - Concrete rehabilitation KW - Repair systems KW - Polymer cement mortar (PCC) KW - Sprayed polymer cement mortar (SPCC) PY - 2011 SN - 978-3-9814523-0-3 SP - 319 EP - 329 AN - OPUS4-23985 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fontana, Patrick A1 - Müller, Urs A1 - Malaga, Katarina A1 - Lagerblad, B. A1 - Meng, Birgit T1 - Precast concrete facade elements with low embodied energy N2 - Concrete is by far the most common building material in the world. Due to its good durability it is widely used in building envelopes. One major part of the embodied energy in concrete comes from the production of Portland cement that consumes around 3,500 MJ energy per each ton of cement. Globally 2.6 billion tons of Portland cement is produced and the consumption is increasing. Since concrete will be used as main building material also in future construction, it is reasonable to develop concrete building components with lower embodied energy.Using the example of an ultra-high performance concrete (UHPC) façade element, it is demonstrated how the embodied energy can be reduced by application of hydrothermal curing. T2 - ENBRI Workshop - reaching the nearly zero-energy goal for buildings CY - Boras, Sweden DA - 04.04.2011 KW - UHPC KW - Betonfertigteil KW - Fassaden KW - Autoklavierung KW - Nachhaltigkeit PY - 2011 SN - 978-91-86622-51-0 SN - 0284-5172 SP - 1 EP - 8 AN - OPUS4-23628 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit T1 - Mikrostruktur und Dauerhaftigkeit zementgebundener Baustoffe T2 - 8. Münchener Baustoffseminar "Dauerhaftigkeit von Betonkonstruktionen - Von den Mechanismen zum Lebensdauermanagement" CY - München, Deutschland DA - 2008-10-10 KW - Beton KW - Gefüge KW - Zement KW - Dauerhaftigkeit PY - 2008 SP - 1 EP - 9 AN - OPUS4-18594 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Urs A1 - Gardei, André A1 - Massah, Sima A1 - Meng, Birgit T1 - Hydraulische Bindemittel KW - Bindemittel KW - Puzzolane KW - Hydraulisch KW - Beton KW - Denkmalpflege PY - 2008 SN - 978-3-86568-451-6 N1 - Serientitel: Berichte zu Forschung und Praxis der Denkmalpflege in Deutschland – Series title: Berichte zu Forschung und Praxis der Denkmalpflege in Deutschland IS - 16 SP - 9 EP - 21 PB - Michael Imhof AN - OPUS4-19087 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bürgisser, Philip A1 - Müller, Urs A1 - Meng, Birgit A1 - Abart, R. ED - Leon Black, ED - Phil Purnell, T1 - Influence of natural pozzolans of mechansims of the alkali silica reaction (ASR) in concrete T2 - 29th Cement and concrete science conference CY - Leeds, UK DA - 2009-09-07 KW - AKR KW - Natürliche puzzolanische Zusatzstoffe KW - C-S-H Phasen PY - 2009 SN - 978-0-85316-281-0 SP - 143 EP - 146 AN - OPUS4-20249 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bürgisser, Philip A1 - Müller, Urs A1 - Meng, Birgit A1 - Abart, R. ED - Stark, J. T1 - Der Einfluss von natürlichen Puzzolanen vulkanischen Ursprungs auf die Alkali-Kieselsäurereaktion (AKR) im Beton T2 - 17. Ibausil - Internationale Baustofftagung CY - Weimar, Germany DA - 2009-09-23 KW - AKR KW - Natürliche puzzolanische Zusatzstoffe KW - C-S-H Phasen PY - 2009 SN - 978-3-00-027265-3 VL - 2 SP - 2-0687 - 2-0692 CY - Weimar AN - OPUS4-20298 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Herbst, Tristan A1 - Hauer, B. A1 - Rübner, Katrin A1 - Meng, Birgit ED - Stark, J. T1 - Nachhaltiges Bauen mit Beton - Einsatz sekundärer Gesteinskörnungen T2 - 17. Ibausil - Internationale Baustofftagung CY - Weimar, Germany DA - 2009-09-23 KW - Sekundärrohstoffe KW - Müllverbrennungsaschen KW - Sekundäre Gesteinskörnung PY - 2009 SN - 978-3-00-027265-3 VL - 2 SP - 2-1273 - 2-1278 CY - Weimar AN - OPUS4-20299 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Vasilic, Ksenija A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten A1 - Meng, Birgit ED - Stark, J. T1 - Experimental and numerical studies on calibration of a rotational rheometer for cementitious materials T2 - 17. Ibausil - Internationale Baustofftagung CY - Weimar, Germany DA - 2009-09-23 PY - 2009 SN - 978-3-00-027265-3 VL - 1 SP - 1-1135 - 1-1140 CY - Weimar AN - OPUS4-20300 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Ramge, Peter A1 - Kühne, Hans-Carsten A1 - Meng, Birgit ED - Stark, J. T1 - Betoninstandsetzung mit modular zusammengesetzten PCC- und SPCC-Mörteln T2 - 17. Ibausil - Internationale Baustofftagung CY - Weimar, Germany DA - 2009-09-23 KW - Betoninstandsetzung KW - Instandsetzungsmörtel KW - Modulare Systeme KW - SPCC KW - PCC PY - 2009 SN - 978-3-00-027265-3 VL - 2 SP - 2-0151 - 2-0156 CY - Weimar AN - OPUS4-20301 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Meng, Birgit A1 - Kühne, Hans-Carsten A1 - Eichhorn, Michael ED - Stark, J. T1 - Performance-Verbesserung bei Betonwerksteinen durch multi-funktionale Nano-Additive T2 - 17. Ibausil - Internationale Baustofftagung CY - Weimar, Germany DA - 2009-09-23 PY - 2009 SN - 978-3-00-027265-3 VL - 2 SP - 2-0675 - 2-0680 CY - Weimar AN - OPUS4-20302 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kargol, Marta A1 - Müller, Urs A1 - Gardei, André A1 - Meng, Birgit T1 - Influence of blended cements on the performance of water repellent agents N2 - Ingress of moisture and harmful ions (e.g. Chloride, sulfate) into cementitious materials is one of the major factors in defining their durability. Modifications of building materials by targeted deposition of surface functional agents that make the surface hydro- and/or oleophobic aim to minimize moisture and ion ingress, and thus extend Service life of the cement based structures. Water repellent and easy-to-clean coatings for inorganic Substrates have gained strong attention during the last few years and various formulations based on silicones or alkylpolysiloxanes have been developed. Cementitious building materials are highly complex Systems with many components and changing properties in the course of a building’s Service life. The interactions between the Chemical agents and the cement based materials depend on many factors. The Chemical properties of the material Substrate appear to be the most important but in the context of their influence on the functionality of silanes and/or siloxanes these characteristics have not been well understood yet. The aim of this study was to evaluate the effect of different blended cements on water repellent agents’ performance. Two organosilicon compounds were applied on fresh blended cements containing limestone (L), fly ash (F), slag (S) and trass (T), and investigated in terms of their functionality. The surface properties of functionalized blended cements were studied based on wettability, i.e. contact angle measurements, before and after exposure to artificial and natural weathering. The first results indicate that slag and trass more distinctly affect the water repellent Surface performance after aging. T2 - Hydrophobe VI - 6th International conference on water repellent treatment of building materials CY - Rome, Italy DA - 12.05.2011 KW - Hydrophobic surfaces KW - Wettability KW - Impregnation KW - Blended cement KW - Silanes PY - 2011 SN - 978-3-931681-99-9 SP - 23 EP - 32 PB - Aedificatio Publishers AN - OPUS4-23681 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stroh, Julia A1 - Meng, Birgit A1 - Emmerling, Franziska T1 - Monitoring of sulphate attack on hardened cement paste studied by synchrotron XRD N2 - The complex matter of external sulphate attack on cement-based construction materials is still not completely understood. The concentration of sulphate is a crucial factor for the formation of secondary phases and phase transitions of cement hydrates due to sulphate ingress into the microstructure. The sulphate attack on building materials for high and low sulphate concentrations was monitored by laboratory experiments. Hardened cement paste consisting of ordinary Portland cement (CEM I) were exposed to aqueous solutions of sodium sulphate for 18 months. Three sample compositions were used for this research, including different supplementary cementitious materials (SCM). The phase composition was determined for different time spans by high resolution synchrotron X-ray diffraction. Cross sections of exposed cement prisms were investigated as a representation of the microstructural profile. Based on the data, a temporal and spatial determination of the stages of the sulphate attack and the deterioration course was possible. Cement matrices blended with slag showed the highest resistance against sulphate attack. KW - Cement paste KW - Sulphate attack KW - Mineral additions KW - Concentration KW - Monitoring PY - 2015 U6 - https://doi.org/10.1016/j.solidstatesciences.2015.08.006 SN - 1293-2558 SN - 1873-3085 VL - 48 SP - 278 EP - 285 PB - Elsevier Masson SAS CY - Amsterdam AN - OPUS4-34281 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weise, Frank A1 - Voland, Katja A1 - Meng, Birgit ED - Ludwig, H.-M. T1 - AKR unter kombinierten Einwirkungen - Rissbildungs- und Transportmechanismen N2 - ln den letzten Jahren sind im deutschen Bundesautobahnnetz verstärkt Schäden an Betonfahrbahndecken aufgetreten, die mit einer Alkali-Kieselsäure-Reaktion (AKR) in Verbindung gebracht werden. Die damit einhergehende oft drastische Reduzierung der Nutzungsdauer der Betonfahrbahndecke führte zu einer starken Intensivierung der Forschung auf diesem Gebiet. Zentraler Forschungsgegenstand war bisher neben der Suche nach geeigneten präventiven betontechnologischen Maßnahmen vor allem die Entwicklung performanceorientierter Prüfverfahren zur AKR-Prävention. Dabei wurden insbesondere die klimatischen Einwirkungen auf die Betonfahrbahndecke und der externe Alkalieintrag zeitraffend simuliert. Die zusätzlich interagierenden mechanischen Einwirkungen aus dem Verkehr fanden bisher keine Berücksichtigung. Vor diesem Hintergrund verfolgt die 2011 eingerichtete und 2015 um weitere drei Jahre verlängerte DFG-Forschergruppe 1498 u. a. das Ziel, den Einfluss einer mechanisch induzierten Vorschädigung (Ermüdungsbeanspruchung) auf den AKR-Schädigungsprozess zu klären. Die hierfür erforderliche Beschreibung der vielfältigen interagierenden Schädigungs- und Transportprozesse erfordert eine enge Verknüpfung von Experimenten mit einer mehrskaligen Modellierung. Die experimentelle Basis bildet die mechanische Vorschädigung (Ermüdung) großformatiger Balken aus einem Fahrbahndeckenbeton mit einem erhöhten AKR-Schädigungspotenzial. Aus diesen Balken werden nach der Ermüdungsbeanspruchung kleinformatige Probekörper gewonnen, an denen die Auswirkungen der mechanischen Vorschädigung auf das Betongefüge und die interagierenden Transport- und Schädigungsprozesse analysiert werden. Das Teilprojekt der SAM hat in diesem Kontext die Aufgabe, ganzheitlich die Rissbildungsprozesse und den interagierenden Eintrag bzw. Auslaugung der Alkalien von der mechanisch induzierten Vorschädigung bis zum AKR-Schädigungsprozess in enger Abstimmung mit den Forschungspartnern zu untersuchen. Den Schwerpunkt dieses Beitrags bildet die Charakterisierung der Rissbildungsprozesse durch die mechanische Vorschädigung und ihrer Auswirkungen auf die interagierenden Transportprozesse. Das schließt die Vorstellung der hierfür angewandten innovative Prüftechniken und Prüfmethodologien ein. T2 - 19. Ibausil - Internationale Baustofftagung CY - Weimar, Germany DA - 16.09.2015 KW - Betonfahrdecke KW - Ermüdung KW - Transportprozess KW - Ultraschall KW - Schallemissionsanalyse KW - Computertomografie KW - Laser-induced breakldown spectroscopy PY - 2015 SN - 978-3-00-050225-5 VL - 1 SP - 1 - 1461 EP - 1 - 1471 AN - OPUS4-34864 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Selleng, Christian A1 - Fontana, Patrick A1 - Meng, Birgit ED - Ludwig, H.-M. T1 - Einfluss der Dauer der hydrothermalen Behandlung auf Festigkeit und Phasenbestand von UHPC N2 - Ultrahochleistungsbeton (UHPC) zeichnet sich durch eine enorme hohe Druckfestigkeit von über 150MPa aus, während er gleichzeitig eine hohe Dichtheit besitzt. Im Schwerpunktprogramm SPP 1182 der DFG sind umfangreiche Untersuchungen zu verschiedensten Aspekten des UHPC durchgeführt worden, sodass die Voraussetzungen für eine breite Anwendung gegeben sind. T2 - 19. Ibausil - Internationale Baustofftagung CY - Weimar, Germany DA - 16.09.2015 PY - 2015 SN - 978-3-00-050225-5 VL - 1 SP - 12-02, 1-521 - 1-528 AN - OPUS4-34866 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lehmann, C. A1 - Meng, Birgit A1 - Nemecek, J. ED - Ludwig, H.-M. T1 - Investigations on the process of autoclaving ultra-high performance concrete (UHPC) N2 - Concrete technology results more and more in the development of materiale with enhanced properties, such as high strength, higher durability and increased ecological compatibility. One exceptional example is Ultra-High Performance Concrete (UHPC). Its advantages are very high compressive strength and an improved durability, caused by their dense micro structure. Curing under water vapor Saturation pressure (autoclaving) can improve these properties by affecting the micro structure and better the mechanical properties of UHPC. Autoclaving leads to an enhanced cement hydration and accelerated reaction rate of supplementary cementitious materials (SCM) and mineral additions, Used at the production of aerated autoclaved concrete (AAC) and sand-lime bricks, the process of autoclaving is well known, especially in highly porous Systems. One well known requirement to autoclave effectively is a porosity of at least 10%. There is no sufficient heat transfer and also not enough water available if the porosity is lower, Nevertheless, autoclaving also works in the dense structure of UHPC with porosities lower than 2%, as former investigations have shown. There is only a visible difference between the outer parts of the samples compared to their core. Investigations on the chemistry, the micro structure as well as the mechanical properties where performed to find an explanation to this effect and to explain the functionality of autoclaving UHPC in spite of the low porosity. T2 - 19. Ibausil - Internationale Baustofftagung CY - Weimar, Germany DA - 16.09.2015 PY - 2015 SN - 978-3-00-050225-5 VL - 2 SP - P2.15, 2-1039 EP - 2-1044 AN - OPUS4-34872 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Przondziono, R. A1 - Timothy, J.J. A1 - Nguyen, M. A1 - Weise, Frank A1 - Breitenbücher, R. A1 - Meschke, G. A1 - Meng, Birgit T1 - Vorschädigungen in Beton infolge zyklischer Beanspruchungen und deren Auswirkung auf Transportprozesse im Hinblick auf eine schädigende AKR N2 - Auf Grundlage der Zielsetzung der Forschergruppe 1498 beschäftigt sich dieser Beitrag mit den Auswirkungen einer zyklischen mechanischen Belastung im Vierpunktbiegeversuch auf das Transportverhalten in Betongefüge. Hierzu wurde zunächst die Degradation des Mikrogefüges mittels Ultraschallmessungen sowie rissmikroskopischen Untersuchungen an Dünnschliffen charakterisiert. Mit dem Ziel der numerischen Modellbildung wurden Untersuchungen zum Wassereindringverhalten durchgeführt. Es wurden u. a. das Wassereindringverhalten über die Zeit und der Einfluss von Vorschädigungen experimentell geprüft. Basierend auf den gewonnenen Erkenntnissen zu den Einzelprozessen des Ionentransports in poröses Gefüge wurde ein mikromechanisches Mehrskalenmodell entwickelt, welches es ermöglicht, die Wirkung der Vorschädigung auf gekoppelte Feuchte- und Ionentransportprozesse vorherzusagen. Das Modell berücksichtigt die Topologie und räumliche Verteilung der Mikrorisse und deren Einfluss auf die Ionendiffusivität. Die numerische Simulation liefert bei anisotroper Verteilung der Mikrorisse eine erhöhte Alkali-Eindringtiefe. ---------------------------------------------------------------------------------------------------------------------------------- According to the goals of the research group 1498, this paper deals with the effects of cyclic flexural loading in a four-point bending test on the fluid transport processes within a concrete structure. Therefore, the degradation of the microstructure is characterized through ultrasonic wave measurements as well as microscopic crack analysis. In order to numerically model these processes, experiments on the penetration behavior of water into the concrete were carried out. The penetration behavior over time as well as the influence of degradation on the water transport were investigated. To predict the influence of concrete degradation on alkali diffusivity, a multi-scale continuum micromechanics model is incorporated into the numerical model, which accounts for the topology and the three-dimensional distribution of microcracks. As expected, the numerical simulation predicts larger alkali-penetration in pre-damaged concrete. Regarding the micro-crack distribution, an anisotropic distribution of micro-cracks tangential to the direction of the alkali and water flux increases their penetration depth. KW - Alkali-Kieselsäure-Reaktion KW - Baustoffe KW - Degradation KW - Ionentransport KW - Mikromechanik KW - Modellierung KW - Straßenbeton KW - Transportprozesse KW - Vorschädigung KW - zyklische Belastung KW - Korrosion KW - Versuche KW - Fahrbahn KW - Cyclic loading KW - Transport process KW - Schädigende AKR KW - ASR damage PY - 2015 U6 - https://doi.org/10.1002/best.201400095 SN - 0005-9900 SN - 1437-1006 VL - 110 IS - 1 SP - 3 EP - 12 PB - Ernst CY - Berlin AN - OPUS4-33039 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Herbst, Tristan A1 - Meng, Birgit T1 - Concept for a holistic sustainability assessment of the end-of-life phase of masonry N2 - In Germany, a quantity of more than 10 million metric tons of masonry rubble is generated per year. With regard to a sustainable closed substance cycle waste management, these rest masses have to be recovered if possible. The end-of-life (EOL) phase of masonry includes the planning steps of demolition, processing and application. The choice of the most sustainable solution raises questions regarding material technology, plant engineering, economic efficiency and ecological issues. For this purpose, a methodological concept for a holistic assessment of the EOL phase of masonry is developed within the scope of a doctoral thesis. For the assessment the Cost-Effectiveness Analysis (CEA) is adapted. The assessment concept enables a holistic comparison of different EOL scenarios for masonry while integrating all planning steps. It combines Material Flow Analysis (MFA), Life Cycle Analysis (LCA), Life Cycle Working Environment (LCWE), economic evaluation methods and material testing. In future, various scenarios can be evaluated with regard to the goals of the European and German waste management industry. KW - sustainability KW - end-of-life phase KW - masonry PY - 2016 U6 - https://doi.org/10.1144/SP416.5 SN - 0375-6440 SN - 0305-8719 SN - 2041-4927 VL - 416 IS - 1 SP - 47 EP - 57 CY - London AN - OPUS4-33166 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schlegel, M.C. A1 - Stroh, Julia A1 - Malaga, K. A1 - Meng, Birgit A1 - Panne, Ulrich A1 - Emmerling, Franziska T1 - Pathway of a damaging mechanism - Analyzing chloride attack by synchrotron based X-ray diffraction N2 - Typically, the changes of the phase compositions due to the chemical attack are studied in-situ only by chemical analysis or microscopy. In this study, the chloride transport and binding in the cement matrix in different cementitious materials was analyzed by synchrotron based X-ray diffraction (SyXRD) and energy dispersive X-ray spectroscopy (EDX). Sample materials consisting of cement paste were embedded in high concentrated sodium chloride solution over different time spans. Afterwards, the phase and chemical compositions were determined. The high spatial resolution and the information about the chloride distribution offer a detailed view of chloride binding in the cement matrix and allow the conclusions about the degradation mechanisms. The results are discussed related to the influence of different supplementary cementitious materials on the damaging mechanism. KW - Portland cement KW - In-situ KW - X-Ray diffraction KW - EDX KW - Durability KW - Chloride attack PY - 2015 U6 - https://doi.org/10.1016/j.solidstatesciences.2015.03.021 SN - 1293-2558 SN - 1873-3085 VL - 44 SP - 45 EP - 54 PB - Elsevier Masson SAS CY - Amsterdam AN - OPUS4-33171 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Werner, Daniel A1 - Gardei, André A1 - Simon, Sebastian A1 - Meng, Birgit T1 - Microscopic investigation of building materials affected by alkali-silica reaction N2 - Concrete is the most applied building material in modern times. It is present in all kinds of structures and no other material secms to rcplace concrete as the most selected building material in the near future. The prime advantages are the high performance, the easy production and a facile processability. The sustainability and durability are important requirements to concrete. Even if concrete is significantly less susceptible against factors promoting a damage, compared to other materials, there are still mechanisms affecting it. In particular, high-ways and hydraulic structures made of concrete worldwide show cases of alkali-silica reaction (ASR) damages. This article refers to experience at BAM Federal InstituteforMaterials Research and Testing for several decades to ASR research and darnage assessment. ASR is a severe darnage mechanism that can occur in concrete, when certain conditions related to composition and cxposition arise in a critical combination. The chemical reaction is based on the alkalis and the silica in the concrete and was first identified by Stanton in highway structures in California (Stanton, 1940). Actually three components are needed to initiate ASR: alkali-sensitive siliceous aggregates, alkalis coming from internal (cement or other components) or external sources (de-icing salt or sea water) and water. If all of these components are sufficiently present an alkali-silica gel could be formed (Hobbs, 1988). This gel itself needs additional space when it is formed. Furthermore it is able to swell in the presence of humidity, both processes generating an expansion pressure inside the concrete. As a consequence of intensive expansion, cracks can occur, which significantly lowers thc strength of the material. Parameters like amount and chemical composition of the gel as weil as the pattern and width of cracks can help to classify the ASR darnage (Swamy, 1992). The objective of this article is to demoostrate the microscopic work on ASR affected concrete samples, carried out to assess the damaging process or to evaluate various alkali-sensitive aggregates. It will explain the approach of ASR investigation from the macroscale to microscale, starting briefly with the condition assessment, over treatment and investigations of samples in the laboratory, to the use of different microscopical and analytical techniques. In the main part the characteristic features for identifying ASR in concrete are presented by using microscopic images. Especially the emphasis lies on the role of the aggregate. T2 - 15th Euroseminar on microscopy applied to building materials CY - Delft, The Netherlands DA - 17.06.2015 KW - Alkali-silica reaction KW - Concrete KW - Damage analysis KW - Materials characterisation KW - Preparation of thin sections PY - 2015 SN - 978-94-6186-480-2 SP - 1 EP - 11 AN - OPUS4-33791 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Selleng, Christian A1 - Meng, Birgit A1 - Gröger, K. A1 - Fontana, Patrick T1 - Einflussgrößen auf die Wirksamkeit einer Wärmebehandlung von Ultrahochfestem Beton (UHFB) T1 - Influencing factors for the effectivity of heat treatment of ultrahigh performance concrete (UHPC) N2 - Mittels Wärmebehandlung lassen sich die hervorragenden Eigenschaften von UHFB nochmals verbessern. Die für eine optimale Umsetzung relevanten Randbedingungen werden aktuell in der Fachwelt diskutiert. In dieser Veröffentlichung werden die Ergebnisse eines Forschungsprojekts vorgestellt, das die Wirkung verschiedener Einflussgrößen bei der Wärmebehandlung auf die Eigenschaften von UHFB zum Thema hatte. Dabei wurden die Art des Schutzes gegen das Austrocknen, die Vorlagerungszeit und die Haltezeit variiert. Um die zugrunde liegenden Prozesse zu verstehen, wurde der Phasenbestand mittels Röntgendiffraktometrie untersucht. Die höchsten Druckfestigkeiten des UHFB ließen sich bei einer Wärmebehandlung mit Wasserlagerung erzielen, da hierbei eine weitere Hydratation begünstigt wird. Vergleichsweise niedriger waren die Steigerungen bei einer Behandlung mit Schutz vor Austrocknung, während eine ungeschützte Behandlung zu deutlich geringeren Festigkeiten führte. Die Vorlagerungszeit beträgt im Idealfall einige Tage, um die Ausbildung eines offenbar günstigen Ausgangsgefüges sicherzustellen. Die Haltezeit sollte möglichst ausgedehnt sein, weil die Hydratation entsprechend lange gefördert wird. Im oberflächennahen Bereich war unter bestimmten Bedingungen eine Zonierung zu beobachten, deren Ursachen und Folgen, insbesondere in Bezug auf die Dauerhaftigkeit, weitere Forschung erfordern. KW - Ultra-Hochleistungsbeton KW - Wärmebehandlung KW - Behandlungsparameter KW - Vorlagerungszeit KW - Haltezeit KW - Festigkeitssteigerung KW - Zonierung KW - Ettringit PY - 2017 U6 - https://doi.org/10.1002/best.201600059 SN - 0005-9900 VL - 112 IS - 1 SP - 12 EP - 21 PB - Ernst & Sohn AN - OPUS4-39171 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Voland, K. A1 - Weise, Frank A1 - Meng, Birgit T1 - Alkali-silica reaction in concrete pavements N2 - A significant number of German concrete motorway pavements have shown damage only a few years after construction. The alkali-silica-reaction (ASR) is often one of the reasons for this damage. German guidelines and regulations focus on the optimisation of the concrete composition to avoid damage due to ASR. Moreover, diverse research projects have dealt with the development and optimisation of ASR performance test methods with and without external alkali supply. However, the influence of other parameters on the occurrence and intensity of a damaging ASR had not yet been taken into account. Such parameters include, e.g., insufficient curing and the modifications of concrete’s porosity due to the use of slip form pavers. Likewise, the increased traffic loading had not yet been considered. The Federal Institute for Materials Research and Testing (BAM) assesses these parameters and processes in a number of projects. These projects aim primarily to increase the durability of the concrete pavements, in particular by improving preventive measures that may be taken before or after the construction of concrete pavements. This paper gives a short overview of BAM’s projects concerning ASR in concrete pavements. Furthermore, results regarding the influence of the cyclic traffic loading on ASR are presented. T2 - 8th International conference on concrete under severe conditions - environment and loading (ConSec) CY - Lecco, Italy DA - 13.09.2016 KW - Alkali-silica-reaction KW - ASR KW - Concrete pavements KW - Durability KW - Concrete's porosity KW - Cyclic traffic loading and mechanical pre-damage PY - 2016 U6 - https://doi.org/10.4028/www.scientific.net/KEM.711.714 SN - 1662-9795 VL - 711 SP - 714 EP - 721 PB - Trans Tech Publications CY - Switzerland AN - OPUS4-39106 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Simon, Sebastian A1 - Selleng, C. A1 - Meng, Birgit T1 - Prompt phase analyses of ultrahigh-performance concrete N2 - Powder X-ray diffraction is a time-consuming and challenging task, especially for preparation of sensitive phases like ettringite and calcium-silicate-hydrate (C-S-H) phases. Fine-grained ultrahigh-performance concrete (UHPC) with an average grain size <100 μm could be investigated directly without time-consuming milling. As a proof of concept, small UHPC cylinders with plain surfaces were investigated with a newly designed sample holder. The comparison with conventionally prepared powder shows the feasibility of fast qualitative phase analysis using this approach. As a great benefit, a depth-dependent analysis, as well as a comparison of surface layers and core material, was carried out. KW - Ultrahigh-performance concrete (UHPC) KW - X-ray diffraction (XRD) KW - Sample holder KW - Fast measurement KW - Spatial analyses PY - 2018 U6 - https://doi.org/10.1061/(ASCE)MT.1943-5533.0002163 SN - 1943-5533 SN - 0899-1561 VL - 30 IS - 3 SP - 06018001, 1 EP - 06018001, 5 PB - American Society of Civil Engineers CY - Reston, VA, USA AN - OPUS4-43879 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Budnik, J. A1 - Betz, T. A1 - Fromm, A. A1 - Gerdes, A. A1 - Gerlach, J. A1 - Götz, M. A1 - Hintzen, W. A1 - Hüttl, R. A1 - Kämpfer, W. A1 - König, A. A1 - Kühner, S. A1 - Lohaus, L. A1 - Meng, Birgit A1 - Neumann, T. A1 - Patzer, M. A1 - Schaab, A. A1 - Schauerte, J. A1 - Siebert, B. A1 - Stephan, D. A1 - Tebbe, H. A1 - Wagner, J.-P. ED - Siebert, B. T1 - Chemischer Angriff auf Betonbauwerke - Bewertung des Angriffsgrads und geeignete Schutzprinzipien N2 - In verschiedenen Bereichen des Betonbaus ist Beton einem chemischen Angriff von außen ausgesetzt, der die Dauerhaftigkeit des betreffenden Bauteils bzw. des gesamten Bauwerks beeinträchtigen kann. Für einen chemischen Angriff in natürlichen Böden und Grundwässern bestehen normative Vorgaben in DIN 4030-1 [R10] bzw. DIN 1045-2 [R19], um den Angriffsgrad anhand der Art und Konzentration der angreifenden Stoffe in Expositionsklassen XA1 (schwach angreifend) bis XA3 (stark angreifend) einzustufen. Hinsichtlich weiterer maßgeblicher Einflussfaktoren wird an dieser Stelle nicht näher differenziert, ob und inwieweit die Regelungen für Böden und Grundwässer auch auf andere Bereiche mit chemischem Angriff auf Beton zu übertragen sind, ist stets im Einzelfall zu überprüfen. Ebenfalls sind die zu treffenden Maßnahmen über die Vorgaben der DIN EN 206-1/DIN 1045-2 [R19] hinaus anwendungsspezifisch festzulegen. Der Hauptausschuss Baustofftechnik (HABT) des DBV hat daher den Arbeitskreis "Chemischer Angriff auf Beton" beauftragt, dieses Merkblatt zu erarbeiten, das Hilfestellung bei der Bewertung einer projektspezifischen chemischen Angriffssituation auf Beton sowie bei der Planung und Ausführung von Schutzprinzipien leisten soll. KW - Beton KW - Betonangriff KW - Dauerhaftigkeit KW - Säureangriff KW - Sulfatangriff PY - 2014 SP - 1 EP - 101 PB - Eigenverlag Deutscher Beton- und Bautechnik-Verein e. V. CY - Berlin AN - OPUS4-44662 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Budnik, J. A1 - Betz, T. A1 - Brameshuber, W. A1 - Fromm, A. A1 - Gerdes, A. A1 - Gerlach, J. A1 - Götz, M. A1 - Hart, R. A1 - Heese, C. A1 - Hintzen, W. A1 - Hüttl, R. A1 - Kämpfer, W. A1 - König, A. A1 - Kühner, S. A1 - Lohaus, L. A1 - Meng, Birgit A1 - Neumann, T. A1 - Remus, R. A1 - Schaab, A. A1 - Schäffel, P. A1 - Schauerte, J. A1 - Schönborn, A. A1 - Siebert, B. A1 - Stephan, D. A1 - Tebbe, H. A1 - Wagner, J.-P. ED - Siebert, B. T1 - Chemischer Angriff auf Beton - Empfehlungen zur Prüfung und Bewertung N2 - ln den letzten Jahren wurden diverse Prüfverfahren und Methoden entwickelt, um die Leistungsfähigkeit von Beton bzw. Bindemittel hinsichtlich des Widerstands gegenüber betonaggressiven Einwirkungen beurteilen zu können. Ein wesentliches Ziel von Prüfverfahren zur Beurteilung der Dauerhaftigkeit von Baustoffen ist, die im Laufe der Nutzungsdauer zu erwartenden Einwirkungen auf den Baustoff realitätsnah abzubilden. Dazu sind die Prüfparameter auf die im jeweiligen Anwendungsbereich vorherrschenden Umgebungs- und Randbedingungen anzupassen. Daneben sind auch die Bewertungskriterien individuell unter Berücksichtigung der im Einzelfall geforderten Nutzungsdauer eines Bauwerks festzulegen. Eine systematische Zuordnung von adäquaten Prüfverfahren bzw. Prüfparametem und Bewertungskriterien für die verschiedenen Anwendungsbereiche im Betonbau, in denen betonaggressive Einwirkungen auftreten, ist mit Ausnahme von Einzelfällen bislang nicht vorhanden. Daneben stellt sich in der Praxis immer wieder das Problem, das Angriffspotenzial der Umgebung eines Bauwerks (prüftechnisch) zu erfassen und zu bewerten. Der Hauptausschuss Baustofftechnik des DBV hat daher den Arbeitskreis „Chemischer Angriff auf Beton“ beauftragt, dieses Merkblatt zu erarbeiten, das auf Basis von einschlägigen Erfahrungen der Baupraxis und wissenschaftlichen Erkenntnissen Grundsätze und bewährte Methoden zur Beurteilung der Einwirkungs- und Widerstandsseite beim chemischen Angriff auf Beton aufzeigt und diesbezüglich Hinweise für verschiedene Anwendungsbereiche im Betonbau liefert. KW - Beton KW - Betonangriff KW - Dauerhaftigkeit KW - Säureangriff PY - 2017 SP - 1 EP - 65 PB - Eigenverlag Deutscher Beton- und Bautechnik-Verein e. V. CY - Berlin AN - OPUS4-44663 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rachmatulin, Natalia A1 - Gardei, André A1 - von Werder, Julia A1 - Meng, Birgit A1 - Süßmuth, J. A1 - Gerdes, A. A1 - Ballschuh, D. A1 - Seibt, H. T1 - Funktionalisierung von Polymerfasern - ein Beitrag der Tensidchemie für dauerhafte zementgebundene Werkstoffe N2 - Im Gegensatz zur Druckfestigkeit weisen zementgebundene Werkstoffe i. a. nur geringe Zugfestigkeiten auf. Ein Weg, Zugfestigkeiten zementgebundener Werkstoffe zu erhöhen und Rissbildung aufgrund von Zugspannungen zu verringern, besteht in der Einarbeitung von Fasern, die diese Spannungen aufnehmen. Häufig eingesetzt werden Stahlfasern, obwohl synthetische Polymerfasern leichter und meist beständiger gegenüber chemischen Angriffen und Korrosion sind. Die Polymerfasern zeigen allerdings meist einen deutlich schwächeren Haftverbund, was an der hydrophoben Faseroberfläche liegt. Um nun eine Anbindung der Fasern an die mineralische Matrix zu erreichen, müssen die Faseroberflächen modifiziert werden, ohne dass die mechanischen Eigenschaften negativ beeinflusst werden. Eine Herausforderung besteht somit in einer Oberflächenmodifikation durch eine schonende Behandlung der Fasern zur Erzeugung von anbindungsfähigen Gruppen. Durch eine Behandlung von modifizierten Fasern mit geeigneten Polymerlösungen werden die Oberflächeneigenschaften verändert und erlauben eine Anbindung an die Zementsteinmatrix. Der Einsatz von Tensiden als grenzflächenaktive Verbindungen ermöglicht in diesem Zusammenhang eine Vermittlung zwischen Polymeroberflächen und mineralischen Werkstoffen. T2 - HighTechMatBau CY - Berlin, Germany DA - 31.01.2018 KW - Zementgebundene Baustoffe KW - Lichtmikroskopie KW - Röntgen-3D-Computertomographie KW - Einzelfaserdurchzugsversuch KW - Windkanal KW - Fasermodifikation KW - Oberflächenfunktionalisierung KW - Grenzflächenaktive Verbindung PY - 2018 SN - 978-3-7388-0082-1 SP - 31 EP - 35 PB - Fraunhofer IRB Verlag CY - Stuttgart AN - OPUS4-44651 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rachmatulin, Natalia A1 - Gardei, André A1 - von Werder, Julia A1 - Meng, Birgit A1 - Süßmuth, J. A1 - Gerdes, A. T1 - Funktionalisierung von Polymerfasern - ein Beitrag der Tensidchemie für dauerhafte zementgebundene Werkstoffe N2 - Im Gegensatz zur Druckfestigkeit weisen zementgebundene Werkstoffe i. a. nur geringe Zugfestigkeiten auf. Ein Weg, Zugfestigkeiten zementgebundener Werkstoffe zu erhöhen und Rissbildung aufgrund von Zugspannungen zu verringern, besteht in der Einarbeitung von Fasern, die diese Spannungen aufnehmen. Häufig eingesetzt werden Stahlfasern, obwohl synthetische Polymerfasern leichter und meist beständiger gegenüber chemischen Angriffen und Korrosion sind. Die Polymerfasern zeigen allerdings meist einen deutlich schwächeren Haftverbund, was an der hydrophoben Faseroberfläche liegt. Um nun eine Anbindung der Fasern an die mineralische Matrix zu erreichen, müssen die Faseroberflächen modifiziert werden, ohne dass die mechanischen Eigenschaften negativ beeinflusst werden. Eine Herausforderung besteht somit in einer Oberflächenmodifikation durch eine schonende Behandlung der Fasern zur Erzeugung von anbindungsfähigen Gruppen. Durch eine Behandlung von modifizierten Fasern mit geeigneten Polymerlösungen werden die Oberflächeneigenschaften verändert und erlauben eine Anbindung an die Zementsteinmatrix. Der Einsatz von Tensiden als grenzflächenaktive Verbindungen ermöglicht in diesem Zusammenhang eine Vermittlung zwischen Polymeroberflächen und mineralischen Werkstoffen. T2 - HighTechMatBau CY - Berlin, Germany DA - 31.01.2018 KW - Zementgebundene Baustoffe KW - Lichtmikroskopie KW - Röntgen-3D-Computertomographie KW - Einzelfaserdurchzugsversuch KW - Windkanal KW - Fasermodifikation KW - Oberflächenfunktionalisierung KW - Grenzflächenaktive Verbindung PY - 2018 AN - OPUS4-44652 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wallau, Wilma A1 - Pirskawetz, Stephan A1 - Voland, K. A1 - Meng, Birgit T1 - Continuous expansion measurement in accelerated concrete prism testing for verifying ASR-expansion models N2 - The susceptibility of concrete structures due to alkali–silica reaction (ASR) can be assessed by means of ASR concrete prism testing at 60 °C, according to RILEM AAR 4.1. There, expansion of concrete prisms indicates alkali-reactivity of the examined concrete mix. This work applies in situ expansion measurement to accelerated concrete prism testing. Automated measuring facilitates both storage without the usually necessary interruptions for manual measurement and acquisition of quasi-continuousexpansion data. A comparative experimental programme showed that conventional testing resulted in stronger expansion and leaching of alkalis than automated testing. Experimental simulation of interruptions, typically associated with manual measurements in conventional testing, could prove the influence of these cooling–heating cycles. Two phenomenological approaches, frequently used for describing reaction kinetics of ASR by linking it to expansion results from ASR-testing, were validated with continuous expansion data of three types of aggregate. Experimental expansion depicted s-shaped curves similar to them of the modelling approaches. However, strong swelling recorded in the beginning of the test was not covered by the model curves. Auxiliary measurement of acoustic emissions and ultrasonic velocity helped characterising mechanisms such as hydration and cracking, which also influence prism expansion. The proposed modification of the measurement procedure provides an extended basis to analyse expansion mechanisms. Regarding data for validation of ASR-expansion models, continuous expansion results are preferable to conventional test results. KW - Alkali–silica reaction KW - Accelerated concrete prism test KW - Automated expansion measurement KW - ASR modelling PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-455959 SN - 1359-5997 SN - 1871-6873 VL - 51 IS - 3 SP - 51 EP - 79 PB - Springer AN - OPUS4-45595 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schraut, Katharina A1 - Adamczyk, Burkart A1 - Simon, Sebastian A1 - von Werder, Julia A1 - Meng, Birgit A1 - Stephan, D. A1 - Kargl, F. A1 - Adam, Christian T1 - Formation and chemical stabilisation of tricalcium-silicate during solidification from the melt of post-treated metallurgical slags N2 - Tricalcium-silicate (C3S) or Alite is the most important mineral in Portland cement. Since pure tricalcium-silicate is only stable above temperatures of 1250 °C, its decomposition has to be prevented technically by fast cooling after the sintering process. At room temperature, the decomposition velocity is very slow so that metastable tricalcium-silicate is obtained. Although the mechanisms of clinker phase formation during burning process of Portland cement in a rotary kiln were solved and improved over the years, in view of possible economic and ecological benefits current projects aim to produce clinker phases from metallurgical slags. Recent studies discovered that the mineral phase which remained after a reducing treatment and separation of formed metallic iron from molten Linz-Donawitz (LD-) slags contained about 60 wt.% Alite despite it was cooled slowly. Because the results could be verified using slags from different origins and varying cooling velocities a chemical stabilisation of the Alite can be assumed. First tests in mortars indicate that workability, hardening and solid state properties are comparable with an ordinary Portland cement. An application of the observed phenomenon in cement production requires enhanced knowledge about formation and stabilisation conditions of Alite during crystallisation from melts in contrast to the sintering reactions in conventional Portland cement production. Therefore, this study focuses on the stabilisation mechanisms of Alite in consolidating melts. Samples from different melting experiments are analysed to determine stabilising factors. T2 - 15th International Congress on the Chemistry of Cement CY - Prag, Czech Republic DA - 16.09.2019 KW - Tricalcium-silicate KW - Portland Cement KW - Alite KW - Steelmaking slag PY - 2019 SP - Paper 492, 1 EP - 10 AN - OPUS4-49050 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Voigt, Marieke A1 - von Werder, Julia A1 - Meng, Birgit T1 - Investigation of the zonation of thermally treated ultra high performance concrete N2 - Ultra high performance concrete (UHPC) is characterised by its high compressive strength of more than 120 MPa and its high durability. With thermal treatment at 90°C, hydration is accelerated and a strength comparable to the 28-day strength can be achieved immediately after the treatment. In applying Optimum process conditions, the strength can be even further increased by up to 30%. Previous Research showed that thermal treatment can lead to inhomogeneities in form of a visible zonation within the cross-section, if the UHPC is not protected sufficiently from desiccation. This led to the question, to what extent the related changes in mechanical properties, microstructure and phase composition are of relevance for the performance of the UHPC. First investigations of small specimens thermally treated without protection exhibited a decrease of compressive strength, indicating that the zonation aspect requires further research. In this study the zonation of UHPC treated thermally at 90°C is investigated after applying four different procedures of treatment and curing in comparison. The samples are characterized with respect to their chemistry, mineral composition and microstructure to allow an assessment on durability and strength development, with focus on potential depth dependent changes associated with the zonation. The measurements reveal the formation of a visible zonation in case of unprotected treatment, if followed by immersion in water. The compressive strength is not significantly impaired, but a decrease in bending strength gives reason for concern. Further results allow clear correlation with changes in pore structure, whereas the interpretation of relationships with phase distribution, degree of hydration, microchemistry is more complex and therefore, provides only partial clarification. KW - UHPC KW - Thermal treatment KW - Zonation KW - Desiccation KW - Microstructure KW - Durability PY - 2020 U6 - https://doi.org/10.1016/j.conbuildmat.2020.119187 VL - 254 SP - 119187 PB - Elsevier Ltd. AN - OPUS4-50828 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stroh, Julia A1 - Schlegel, Moritz-Caspar A1 - Schmidt, Wolfram A1 - Nguyen, Thi Yen A1 - Meng, Birgit A1 - Emmerling, Franziska T1 - Time-resolved in situ investigation of Portland cement hydration influenced by chemical admixtures N2 - Numerous admixtures are used in the building practice to customize the properties of the cement paste during application. The influences of admixtures on the course of cement hydration and formation of hydrate phases have to be considered. Polycarboxylate ether (PCE) based polymeric superplasticizers (SPs) are known to retard the setting of the cement paste. The extent of the retardation differs depending on the molecular structure of the SP. Additionally, the presence of a stabilizing agent (SA) in the cement paste has a retarding side effect on the setting. The initial cement hydration processes and the detailed mechanisms of the retardation influenced by PCEs, as well as their interactions with particular SAs, are insufficiently understood. Up to now, only the results of phenomenological studies were taken into account to describe this retardation process. A detailed structure analysis monitoring the change of the phase composition during the hydration was never applied. Both SP and SA affect the adsorption of the sulphate ions on the clinker particles, causing changes in the formation of ettringite during the initial hydration, and are therefore a crucial part of the setting process itself. Here, the initial hydration of cement influenced by the interaction of SP and SA was monitored in situ by synchrotron X-ray diffraction. The high time resolution of the measurements allowed a continuous detection of the hydrates formed. The hydration was followed from the starting point of water addition and for couple of hours afterwards. The hydration of the levitated cement pellets containing starch as SA was initialized by adding aqueous solutions of different commercial SPs. Changes in the ettringite formation were detected in comparison to the reference hydration of pure cement. KW - Synchrotron KW - Portland cement Initial hydration KW - Superplasticizer KW - Stabilizer KW - XRD PY - 2016 U6 - https://doi.org/http://dx.doi.org/10.1016/j.conbuildmat.2015.12.097 IS - 106 SP - 18 EP - 26 PB - Elsevier AN - OPUS4-35467 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Giebson, C. A1 - Voland, Katja A1 - Ludwig, H.-M. A1 - Meng, Birgit T1 - Untersuchungen zur Alkali-Kieselsäure-Reaktion in vorgeschädigten Fahrbahndeckenbetonen N2 - In Betonbauteilen unter gleichzeitiger zyklischer Beanspruchung und externer Alkalizufuhr ist die Gefahr von Schäden infolge oder unter Mitwirkung einer Alkali-Kieselsäure-Reaktion (AKR) besonders hoch. Dies betrifft insbesondere Fahrbahndecken, bedingt durch den zunehmenden Schwerlastverkehr und den winterlichen Auftrag des Enteisungsmittels NaCl. Speziell die Rolle einer mechanischen Vorschädigung des Betons infolge der Verkehrsbeanspruchungen auf den Ablauf einer AKR ist dabei aber noch nicht in ausreichendem Umfang geklärt. Ein Teil der dazu seit 2012 durchgeführten Untersuchungen im Rahmen der DFG-Forschergruppe 1498 soll im Folgenden vorgestellt werden. Es zeigte sich, dass eine AKR in definiert mechanisch vorgeschädigten Betonprobekörpern mit alkalireaktiven Gesteinskörnungen und unter äußerer Alkalizufuhr vor allem früher beginnt als in äquivalenten Probekörpern ohne Vorschädigung. Grund dafür ist das schnellere und tiefere Eindringen von Wasser und insbesondere gelöstem NaCl in den Beton, wodurch Na-Ionen als Reaktionspartner für eine AKR früher und langfristig auch in größerer Menge verfügbar sind.------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ In concrete elements, simultaneously subjected to cyclic loadings and external alkalis, the risk for damages caused by or under participation of an alkali-silica reaction (ASR) is particularly high. This concerns especially concrete pavements due to the increasing heavy load traffic and the wintry application of NaCl deicer. Notably the role of a mechanical pre-damage of concrete caused by traffic loadings on the course of the ASR is largely unclear. A part of the investigations that has been conducted since 2012 into this issue within the scope of the DFG (German research foundation) funded research group 1498 shall be introduced in the following. It was evident that an ASR in defined mechanically pre-damaged concrete prisms with alkali-reactive aggregates and under an external supply of alkalis started earlier than in equal prisms without a pre-damage. The reason for this is the faster and deeper ingress of water and particularly of dissolved NaCl into the concrete, by what Na ions as reaction partner for an ASR are available earlier and, in the long-term, in greater amounts too. KW - Alkali-Kieselsäure-Reaktion KW - AKR KW - Äußere Alkalizufuhr KW - Fahrbahndeckenbetone KW - Mechanische Vorschädigung KW - Versuche KW - Korrosion KW - Baustoff PY - 2015 U6 - https://doi.org/10.1002/best.201400094 SN - 0005-9900 SN - 1437-1006 VL - 110 IS - 1 SP - 13 EP - 21 PB - Ernst CY - Berlin AN - OPUS4-32431 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - Effects of the characteristics of high range water reducing agents and the water to powder ratio on rheological and setting behavior of self-consolidating concrete N2 - To design robust self-consolidating concrete (SCC) for various environmental conditions, it is essential to understand the relevant mechanisms that control the flow performance. This paper depicts how high range water reducing agents (HRWRAs) interact with clinker and hydration phases, and it discusses the important role of the charge density of polycarboxylic HRWRAs in the way the rheology is affected. Based on the rheometric investigations on SCC mixture compositions with different water to powder ratios (w/p) and observations of their pastes' Vicat setting times, the study shows that increasing charge densities of the HRWRA and decreasing w/p reduce the flow retention and have lesser retarding effect on the setting. Based on the test results and discussions optimization procedures for the mixture composition and the HRWRA modification are suggested to achieve optimized performance for varying environmental situations and highest robustness for specific conditions. KW - Polycarboxylate KW - HRWRA KW - Robustness KW - Rheology KW - Self-consolidating concrete PY - 2014 U6 - https://doi.org/10.1520/ACEM20130094 SN - 2165-3984 VL - 3 IS - 2 SP - 1 EP - 15 PB - ASTM International CY - West Conshohocken, Pa., USA AN - OPUS4-30388 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stroh, Julia A1 - Meng, Birgit A1 - Emmerling, Franziska T1 - Deterioration of hardened cement paste under combined sulphatechloride attack investigated by synchrotron XRD N2 - The exact mechanisms of the phase transitions caused by a combined sulphate-chloride attack are discussed controversially. The main points concern the mutual influences of sulphate and chloride ions during the secondary binding processes of these anions within cement hydrate phases. We simulated combined sulphate-chloride attack under laboratory conditions using solutions containing NaCl and Na2SO4 in different concentrations. Three sample compositions were used for the preparation of the specimens. In two of them, 30% of Portland cement was replaced by supplementary cementitious materials (fly ash, slag). The phase distribution in the samples was determined using synchrotron X-ray diffraction. The analysis with high spatial resolution allows the localisation of the secondary phase formation in the microstructural profile of the sample. A mechanism of the phase developments under combined sulphate-chloride attack is derived. KW - Cement paste KW - Sulphate-chloride attack KW - Portland cement KW - Mineral additions PY - 2016 U6 - https://doi.org/10.1016/j.solidstatesciences.2016.04.002 IS - 56 SP - 29 EP - 44 PB - Elsevier Masson SAS CY - Issy les Moulineaux cedex; France AN - OPUS4-35936 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Breitenbücher, R. A1 - Przondziono, R. A1 - Meng, Birgit A1 - Krütt, Enno A1 - Weise, Frank T1 - Alkali-Kieselsäure-Reaktion in Betonfahrbahndecken unter Berücksichtigung von Verkehr und Taumitteln N2 - In Betonfahrbahndecken treten häufig Schäden auf, welche mit einer Alkali-Kieselsäure-Reaktion (AKR) in Verbindung gebracht werden. Obwohl die Hintergründe einer solchen AKR intensiv untersucht wurden, gibt es bei Betonfahrbahndecken besondere Randbedingungen, welche die Schadreaktion signifikant erhöhen können. Diese sind vor allem die Überlagerung der mikrostrukturellen Degradation durch Verkehrsbeanspruchung mit externer Alkali-Zufuhr durch Taumittel. Bisherige Untersuchungen der AKR beschränkten sich auf die Ausgangsstoffe (Gesteinskörnung, Zement, Bewertung des Betons), wobei die besonderen Randbedingungen außer Acht gelassen wurden. Betonfahrbahndecken sind zyklischen Belastungen aus Verkehr und Witterungsbedingungen ausgesetzt. In einem gemeinschaftlichen Forschungsprojekt wurden die verschiedenen, gegenseitig voneinander abhängigen, Einflussfaktoren auf eine schädigende AKR in Betonfahrbahndecken sowohl experimentell untersucht als auch numerisch modelliert. Auf Mikro-Ebene wurden die AKR-bezogenen Transportprozesse innerhalb der Gesteinskörnung, sowie die Gelbildung und der Ionen-Transport, untersucht. Auf Meso-Ebene fokussierte das Projekt auf die Charakterisierung der durch zyklische Belastung induzierten Schädigung im Mikrogefüge des Betons. Des Weiteren wurde das Transportverhalten in ein derart geschädigtes Betongefüge mit und ohne Berücksichtigung des zusätzlichen Einflusses überrollender Reifen beschrieben und dessen Auswirkung auf eine AKR analysiert. Schließlich wurde auf Makro-Ebene das Risiko eines AKR-bedingten Schadens bewertet. Einige ausgewählte Ergebnisse werden in diesem Beitrag dargestellt. KW - AKR KW - Zyklischen Belastung KW - Degradation KW - Flüssigkeitstransport KW - Verkehr PY - 2019 VL - 8 SP - 1 EP - 15 PB - Kirschbaum Verlag GmbH CY - Bonn AN - OPUS4-49153 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krütt, Enno A1 - Wallau, Wilma A1 - Meng, Birgit A1 - Greim, M. A1 - Pirskawetz, Stephan T1 - Automatisierte AKR-Prüfung im 60 °C-Betonversuch T1 - Automated ASR Concrete Prism Testing at 60 degrees C N2 - Der 60 °C-Betonversuch ist eine in Deutschland und international verbreitete Methode um die Empfindlichkeit von Gesteinskörnungen und Betonen hinsichtlich einer Alkali-Kieselsäure Reaktion (AKR) zu prüfen. Dieser Beitrag stellt eine neuentwickelte automatisierte Variante der Prüfmethode in einem Minireaktor vor. Dabei werden die Dehnungen von Betonprismen nicht, wie beim konventionellen Test manuell, sondern automatisch in entsprechend ausgerüsteten Prüfbehältern gemessen. Neben einer Reduzierung des Messaufwands bringt die automatisierte Prüfung im Minireaktor weitere Vorteile. Die Dehnungssignale werden, anders als bei der konventionellen Messung, quasi-kontinuierlich aufgezeichnet und bilden das Expansionsverhalten der Prismen detailliert ab. Außerdem bleiben Unterbrechungen der AKR-provozierenden Lagerung aus, die bei der konventionellen Prüfung notwendig sind. Im Beitrag werden die automatisierte und konventionelle Prüfung anhand der Dehnungen von Prismen zweier Gesteinskörnungen verglichen. In Übereinstimmung mit vorhergehenden Untersuchungen sind im Minireaktor gemessene Dehnungen systematisch kleiner als manuell gemessene. Als mögliche Ursache werden Unterschiede im Auslaugverhalten experimentell untersucht. Zur Überprüfung der Einstufung der zwei Gesteinskörnungen erfolgen außerdem Referenzprüfungen in der Nebelkammerlagerung bei 40 °C. N2 - The Concrete Prism Test at 60 °C (60 °C-CPT) is a common method to evaluate the susceptibility of concrete and aggregates to the Alkali-Silica Reaction (ASR). This paper presents a new device for an automated version of the 60 °C-CPT. The system monitors the expansion of concrete prism automatically. Compared to the conventional test method, effort and time consumption are notably reduced. The nearly continuous recording of expansion signals allows for studying of ASR-mechanisms in more detail than the conventional test. In addition, the interruptions of ASR-provoking storage, necessary for manual measurements, are avoided. The presented study compares results of conventional and automated testing of two types of aggregate. In accordance with previous findings, continuously stored prisms generally expand less than the conventionally tested prisms. To find a possible explanation, differences in leaching of alkali from the concrete prisms were quantified. For verifying the alkali-reactivity of the two aggregates, they were also classified in the fog chamber test at 40 °C, the German reference method. KW - Baustoffe KW - AKR KW - 60 °C-Betonversuch KW - Automatische Dehnungsmessung KW - Auslaugung KW - Building Materials KW - ASR KW - Concrete Prism Test at 60 °C KW - Automated expansion measurement KW - Leaching of alkalis PY - 2019 U6 - https://doi.org/10.1002/best.201900040 SN - 1437-1006 SN - 0005-9900 VL - 114. Jahrgang IS - 12 SP - 911 EP - 918 PB - Ernst & Sohn AN - OPUS4-50062 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - von Werder, Julia A1 - Gardei, André A1 - Hoppe, Johannes A1 - Meng, Birgit ED - Littmann, K. T1 - Funktionalisierung von Fasern für zementgebundene Materialien - ausgewählte Prüfmethoden N2 - Die geringe Zugfestigkeit von zementgebundenen Materialien kann durch die Zugabe von Fasern maßgeblich verbessert werden. Ziel eines gemeinsamen Verbundprojekts mit einem Industriepartner war die Erhöhung der Leistungsfähigkeit von kurzen Polymer- und Carbonfasern durch eine Verbesserung des Verbundes zwischen Faseroberfläche und Zementsteinmatrix. Von der IONYS AG wurde dazu eine spezielle Funktionalisierung entwickelt, die über eine Hydrophilisierung der Faseroberfläche eine chemische Anbindung an die Zementsteinmatrix gewährleistet. Aufgabe der BAM war es, die Effizienz der neuen Beschichtung bezüglich der Erhöhung der Nachrissbiegezugfestigkeit und der Reduzierung der Schwindrissbildung während der Erhärtungsphase zu quantifizieren. Die Ergebnisse zeigen, dass die Funktionalisierung die Neigung zur Schwindrissbildung für die Carbonfasern und in noch stärkerem Maße für die Polymerfasern reduziert. Eine Erhöhung der Nachrissbiegezugfestigkeit konnte dagegen nur für die deutlich steiferen Carbonfasern nachgewiesen werden. T2 - 10. Kolloquium Industrieböden CY - Esslingen, Germany DA - 03.03.2020 KW - Fibres KW - Cementitious materials KW - Shrinkage KW - Strain hardening PY - 2020 SN - 978-3-8169-3505-6 SP - 173 EP - 178 PB - expert Verlag GmbH CY - Tübingen AN - OPUS4-51915 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - von Werder, Julia A1 - Bilgin, S. A1 - Hoppe, Johannes A1 - Fontana, P. A1 - Meng, Birgit ED - Middendorf, B. ED - Fehling, E. ED - Wetzel, A. T1 - Composite UHPC facade elements with self-cleaning surface: Aspects of technological manufacturing N2 - In the framework of the European collaborative project H-House, which was finished in 2017, large façade elements were developed consisting of a box shaped external shell of ultra-high-performance concrete (UHPC) with a functionalized surface and an insulation of autoclaved aerated concrete (AAC). The exposed concrete of the elements was further refined by adding self-cleaning properties to the surface through imprinting a microstructure in combination with chemical agents directly in the casting process. The paper focuses on selected technological aspects of the manufacturing process of large-scale prototypes. Presented are results of the upscaling process of functionalized surfaces from small specimen up to large UHPC composite facade elements produced for the construction of a demonstrator. T2 - 5th International Symposium on Ultra-High Performance Concrete and High Performance Construction Materials (HiPerMat 2020) CY - Kassel, Germany DA - 11.03.2020 KW - Ultra-High Performance Concrete KW - Facade Elements KW - Self-Cleaning Properties KW - Architectural Concrete PY - 2020 SN - 978-3-7376-0828-2 U6 - https://doi.org/10.17170/kobra-202002271026 IS - 32 SP - 51 EP - 52 PB - kassel university press CY - Kassel AN - OPUS4-51908 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krütt, Enno A1 - Weise, Frank A1 - Meng, Birgit T1 - Einfluss einer druckschwellinduzierten Degradation von Fahrbahndeckenbeton auf die schädigende AKR T1 - Influence of cyclic compressive loading induced degradation of road pavement concrete on harmful AAR N2 - In den letzten Jahren sind im deutschen Bundesautobahnnetz verstärkt Schäden an vor 2005 errichteten Betonfahrbahndecken aufgetreten, die mit einer Alkali-Kieselsäure-Reaktion (AKR) in Verbindung gebracht werden. Neben dem AKR-fördernden Einfluss von alkalihaltigen Taumitteln werden Fahrbahndecken zyklischen mechanischen Belastungen infolge des Verkehrs und Zwangsspannungen durch klimatische Einwirkungen ausgesetzt. Solche mechanischen Belastungen werden bisher in keinem AKR-Prüfverfahren berücksichtigt. Die zyklischen Belastungen können zu einer Degradation des Betongefüges führen, die ggf. einen AKR-fördernden Einfluss hat. Dieser Beitrag stellt Untersuchungen vor, die zur Beantwortung der Frage nach dem Einfluss einer zyklischen mechanischen Belastung auf den AKR-Schadensprozess beitragen. Dabei wird der Hypothese nachgegangen, dass die ermüdungsinduzierte Degradation zu einer Erhöhung des Stofftransports führt. Dieser hat einen Einfluss auf die AKR-Schadensentwicklung, da die Reaktionspartner zunächst zum Reaktionsort transportiert werden müssen. Daher wird angenommen, dass sich mit dem Stofftransport auch die AKR-Schädigung verstärkt. Es werden Betonproben aus typischen Fahrbahndeckenbetonen einer vorgeschalteten zyklischen Druckschwellbelastung ausgesetzt. Die Degradation infolge der Vorbelastung wird simultan mittels ZfP-Verfahren charakterisiert. Anschließend werden die Auswirkungen der zyklischen Vorschädigung auf den Stofftransport sowie auf die AKR vergleichend an Prüfkörpern ohne und mit Vorschädigung untersucht. Die Ergebnisse lassen den Schluss zu, dass die zyklische Vorschädigung sowohl den Stofftransport als auch die AKR fördert. N2 - In recent years the German motorway network has seen an increase in the occurrence of damage to concrete road surfaces built before 2005, which can be attributed to the alkali-silica reaction (ASR). In addition to exposure to ASR-stimulating alkalirich deicing-agents, road surfaces are also subjected to cyclical mechanical loading resulting from traffic and induced stresses due to climatic impact. Such mechanical loadings are not considered in any of the previously developed ASR testing procedures. This cyclical loading could, however, lead to a degradation of the concrete microstructure and, in turn, stimulate the ASR-process. This article presents investigations that contribute to answering the question of whether a mechanically induced degradation influences the ASR-process. The hypothesis that the mechanically induced degradation leads to an increase in mass transport is examined. The mass transport is important for the ASR process because the reactants need to be transported to the reaction location before the reaction can take place. Therefore, it is assumed that increased mass Transport also leads to increased ASR damage. Concrete specimens made of typical pavement concretes are subjected to a predamaging cyclic compressive loading. The degradation is characterized simultaneously during the pre-damaging process using non-destructive testing (NDT) techniques. Then the effects of the cyclical pre-damage on the mass transport as well as on the ASR are determined by comparing results from test specimens with and without pre-damage. The results lead to the conclusion that the cyclical pre-damage increases both the mass transport and the ASR. KW - Stofftransport KW - Betonfahrbahndecken KW - AKR KW - Zyklische Belastung KW - Degradation PY - 2020 U6 - https://doi.org/10.1002/best.202000017 SN - 0005-9900 VL - 115 IS - 10 SP - 779 EP - 788 PB - Wilhelm Ernst & Sohn CY - Berlin AN - OPUS4-51561 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Simon, Sebastian A1 - Sigmund, Sandra A1 - Ziemann, M. A. A1 - von Werder, Julia T1 - Characterization of Alkali-Silica Reaction Products by means of Raman Spectroscopy before and after Application of Accelerated Tests N2 - Alkali silica reaction (ASR) is a major concrete durability problem resulting in significant maintenance and reconstruction costs for concrete infrastructures all over the world. To determine whether an aggregate is potentially reactive, accelerated concrete tests are used. Aim of this study is the chemical and microstructural characterization of ASR-products formed under the performance conditions of motorway pavements and during subsequent tests on the remaining ASR susceptibility. Samples were taken from concrete motorway pavements. Some of the samples already showed first indications for beginning damages whereas others showed deteriorations only after applying a performance testing procedure for the estimation of future risk of ASR damage. In a first step ASR-products were identified by polarized light microscopy in thin sections. The reaction products where then analyzed by Raman Spectroscopy and finally the chemical composition of the ASR-products was identified by SEM with EDX. The results indicate that most reaction products show an increasing Ca/Si-ratio with progressive crack length. If an ASR-product develops inside an aggregate and moves through the cement paste, it has a high (Na+K)/Si-ratio at the beginning which decreases with increasing distance from its place of origin. The Raman spectra of the ASR-products are characterized by two broad bands indicating specific Q-species of different amorphous gel networks. Within the scope of the analysis distinctions in the microstructure and the chemical composition of the ASR-gels were detected relating to various conditions of accelerated testing. T2 - 15th International Congress on Chemistry of Cement CY - Prague, Czech Republic DA - 16.09.2019 KW - Alkali-silica reaction KW - Raman microscopy KW - Microstructure KW - Concrete motorway pavements KW - Performance test PY - 2019 AN - OPUS4-49527 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Frei, Vivian A1 - Thiele, Marc A1 - Pirskawetz, Stephan A1 - Meng, Birgit A1 - Rogge, Andreas T1 - Characterizing the Fatigue Behavior of High-Performance Concrete for Wind Energy Structures N2 - Severe mechanical fatigue conditions for worldwide proliferating windfarms are a Major challenge for high-performance concrete in towers, connecting joints and foundations of wind turbines. High-performance concrete offers potential for the application in offshore windfarms, not only regarding its good mechanical, but also chemical resistivity due to low diffusivity in the highly densified microstructure. For a more reliable fatigue assessment, monitoring based on nondestructive testing can be a valuable complement to design rules. Both approaches demand reliable experimental data, information about scalability and the development of standardized testing methods. This article presents results of an ongoing research program of BAM (Bundesanstalt für Materialforschung und -prüfung), which is a part of a joint national project (WinConFat) funded by the German Federal Ministry for Economic Affairs and Energy. The subproject implemented by BAM examines the fatigue behavior in dependence of size and slenderness for varying concrete strength at different stress levels. Besides fatigue strength, nondestructive testing is carried out additionally. Methods used are strain measurement and ultrasonic testing. The change of strain, stiffness and ultrasonic pulse velocity in the fatigue process is discussed. Results disclose a deeper insight into the damage process under cyclic loading of high-performance concrete and contribute to improve nondestructive monitoring. T2 - LORCENIS - Long Lasting Reinforced Concrete fpr Energy Infrastructure under Severe Operating Conditions CY - Ghent, Belgium DA - 10.09.2019 KW - Compressive Cyclic loading KW - Fatigue KW - High-strength concrete KW - Non destructive testing KW - Ultrasonic testing PY - 2019 SN - 978-9-463-88638-3 SP - 1 EP - 4 AN - OPUS4-49500 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Voigt, Marieke A1 - von Werder, Julia A1 - Meng, Birgit ED - Caprai, V. ED - Brouwers, H. J. H. T1 - Investigation of the zonation of thermally treated ultra high performance concrete N2 - Ultra high performance concrete (UHPC) is characterised by its high compressive strength of more than 150 MPa and its high durability. Due to thermal treatment at 90°C a strength comparable to the 28-days-strength can be achieved immediately after the treatment and in some cases can be even further increased up to 30 %. The explanations for the increase in strength are the accelerated hydration of the clinker minerals and the intensified pozzolanic reaction contributing to a denser microstructure and hence, a high performance in compressive strength. Former research shows that thermal treatment can lead to inhomogeneities in form of a visible zonation within the cross-section. The width of the margin increases with shorter pre-storage time before the thermal treatment and with omitting protective measures against desiccation during the treatment. Specimens exhibiting a zonation typically show a lower compressive strength compared to the undisturbed reference whereas changes in chemistry, mineral content and microstructure were not reported in detail. In this study the zonation of thermally treated UHPC is investigated with respect to its chemistry, mineral composition and microstructure to allow predictions on durability and strength development. Measurements show a change in pore sizes, minerals phase composition and element distribution leading to the visible zonation and weaker bending tensile strength compared to the reference. T2 - 2nd International Conference of Sustainable Building Materials CY - Eindhoven, Netherlands DA - 12.08.2019 KW - UHPC KW - Thermal treatment KW - Zonation KW - Desiccation KW - Microstructure KW - Durability PY - 2019 VL - 2 SP - 185 EP - 193 AN - OPUS4-49479 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - von Werder, Julia A1 - Gardei, André A1 - Meng, Birgit ED - Caprai, V. ED - Brouwers, H. J. H. T1 - Functionalization of fibres for cement-based materials - selected test methods N2 - The low tensile strength of cement-based materials can be improved by the addition of fibres. In a joint research project, an industrial partner designed special coatings for polymer and carbon fibres by integrating surfactants and hydrophilic compounds. Aim of the developed functionalization was to ensure an even coverage of the fibre surfaces and to anchor them chemically in the cement-based matrix. Task of the BAM was to quantify the effect of the improved bond. In a first step a workable mortar adjusted to the strength of the tested fibres was developed and the fibre distribution assessed by light microscopy and computed tomography. To test the new coating for its efficiency to prevent cracking during hardening and to improve the loadbearing behaviour new test setups were developed or existing methods were adjusted. The experiments showed that the functionalization leads to a reduction of the crack area measured after the exposure of the wet mortar to strong drying conditions in the wind channel. Regarding the Efficiency to mitigate shrinkage cracks the functionalisation turned out to be more efficient for fibres made from polyacrylonitrile (PAN) than for carbon fibres. An improvement of the tensile strength after cracking of the cementitious matrix could only be documented for the coated carbon fibres. It could be quantified, however, only in the three-point bending tests because the fibres turned out to be too brittle for the applied single fibre pull-through test. T2 - 2nd International Conference on Sustainable Building Materials CY - Eindhoven, Netherlands DA - 12.08.2019 KW - Fibres KW - Functionalization KW - Mortar KW - Computed tomography KW - Shrinkage PY - 2019 VL - 5 SP - 16 EP - 25 AN - OPUS4-49480 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - von Werder, Julia A1 - Simon, Sebastian A1 - Meng, Birgit ED - Gemrich, J. T1 - Hydrothermal Treatment of Ultra-High-Performance Concrete: Mechanical Properties and Phase Composition N2 - The advantages of treating prefabricated components made of Ultra-High-Performance Concrete (UCPC) at 90 °C are largely recognized, while hydrothermal treatment at 185 °C and the corresponding saturation pressure of 1.1 MPa, in contrast, is not applied in building practice so far and was studied only by a few researchers. In the research presented, the parameters pre-storage-time before treatment and dwell time in the autoclave were systematically varied. The results illustrate in which way compressive strength increases with the duration of treatment. Already samples which were only heated up and immediately cooled down show an increase in strength compared to the 28-day reference of about 10 %. After 20 h the maximum increase of about 25 % is reached. Interestingly the compressive strength of samples treated very long hardly decreases. It can be therefore concluded that for the composition investigated the achievable mechanical strength is not severely sensitive regarding the duration of the treatment. Also, pre-storage times before autoclaving longer than 0.5 days showed no significant impact on strength development. The phase composition measured by XRD exhibits significant changes compared to the reference. The amount of ettringite and portlandite have vanished, the cement clinker phases are substantially decreased and hydroxylellestadite and hydrogarnet are formed as new phases. The increase in strength can be assigned to an improved pozzolanic and hydraulic reaction. Contradictory to literature, there was found no tobermorite, a mineral which is known to be susceptible for disintegration at Long autoclaving duration. This explains why no significant strength loss appeared. T2 - 15th International Congress on the Chemistry of Cement CY - Prague, Czech Republik DA - 16.09.2019 KW - Hydrothermal treatment KW - UHPC KW - Phase composition KW - Mechanical strength PY - 2019 SN - 2523-935X SP - 1 EP - 11 AN - OPUS4-49481 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - von Werder, Julia A1 - Fontana, P. A1 - Hoppe, Johannes A1 - Bilgin, S. A1 - Meng, Birgit ED - Serrat, C. ED - Casas, J. R. ED - Gibert, V. T1 - Composite Facade Elements with Self-Cleaning Surface made of Ultra-High-Performance Concrete (UHPC) N2 - In the framework of the European project H-House various concrete façade elements were developed with the aim to ensure a long service life by combining a very durable material with self-cleaning properties. The façade elements presented are made of a shell of UHPC filled with blocks of aerated autoclaved concrete as insulating material. Self-cleaning properties were realized amongst others by imprinting a microstructure into the surface during casting. The paper focuses on selected technological aspects of the manufacturing process of prototypes which had to be performed in two concreting sections. Furthermore the challenges faced when upscaling the self-cleaning properties are addressed and the strategy to assess the self-cleaning properties by measuring the contact and the roll-off angel is presented. The results show that a successfull upscalaing process requires detailed planning and that the best results can often be achieved with a moderate work effort or material use. T2 - XV International Conference on Durability of Building Materials and Components (DBMC 2020) CY - Online meeting DA - 20.10.2020 KW - Ultra-High-Performance Concrete KW - Facade Elements KW - Self-Cleaning Properties KW - Adhesive Pull-Strength KW - Microstructure KW - Architectural Concrete PY - 2020 SN - 978-84-121101-8-0 SP - 1289 EP - 1297 PB - International Center for Numerical Methods in Engineering (CIMNE) CY - Spain AN - OPUS4-51967 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tian, H. A1 - Voigt, Marieke A1 - Lehmann, C. A1 - Meng, Birgit A1 - Stephan, D. ED - Middendorf, B. ED - Fehling, E. T1 - Composition and microstructure stability of cement compound under cyclic hydrothermal condition N2 - There have been many researches focused on the performance improvement of ultra-high performance concrete (UHPC) by autoclaving treatment. The goal of autoclaving is to increase the pozzolanic reaction, and to densify the cement stone and the transition zone which originates from the incorporation of supplementary cementitious materials (SCMs), such as silica fume, fly ash and blast furnace slag. Due to the superior properties, UHPC can also be utilized under high mechanical load and aggressive condition, for example, the fabrication of water tanks for thermal storage which is of great significance for saving energy and reducing CO2 emission. It is known that mineral stability of the hydration products of an inorganic binder is highly related to the temperature and pressure of the environment. A certain stable composition at room temperature, however, may undergo a phase transformation at high temperature and the performance decrease under this severe condition will generally be more severe. In this way, the rationale behind this deterioration under long-term hydrothermal condition involving many cycles and long duration has to be clarified, and then appropriate optimizing methods will be performed in order to obtain a kind of construction with high durability under aggressive environment. For this purpose, different types and amounts of SCMs are introduced into the standard mixture of UHPC and the phase compositions after autoclaving at 200 °C and 15.5 bar are determined by combined X-ray diffraction and scanning electron microscope. Mercury intrusion porosimeter is used to characterise the microstructure of the samples. In order to establish the relationship between microstructure and macroscopic properties, compressive and flexural strength are also investigated. T2 - HiPerMat 2020 CY - Kassel, Germany DA - 11.03.2020 KW - Hydrothermal treatment KW - UHPC KW - Composition PY - 2020 SN - 978-3-7376-0828-2 VL - 23 SP - 87 EP - 88 PB - Kassel University Press CY - Kassel AN - OPUS4-52375 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Voigt, Marieke A1 - von Werder, Julia A1 - Meng, Birgit ED - Middendorf, B. ED - Fehling, E. T1 - Microstructure analysis of thermally treated ultra high performance concrete in the context of the durability performance N2 - Ultra high performance concrete (UHPC) is known for its high compressive strength of more than 150 MPa and its high durability. Thermal treatment at 90°C can accelerate the strength development so that the 28-days-strength can be achieved immediately after the treatment and an additional increase up to 30 % in some cases. The reason for the strength development is an accelerated hydration of the clinker minerals and an intensified pozzolanic reaction leading to a denser microstructure. In previous research inhomogeneities in form of a zonation after unprotected thermal treatment were observed and analysed in respect to changes in the microstructure. This zonation is defined by a different microstructure in the core compared to the outer zone in the matter of porosity, mineral phase composition and a significant change in the potassium and sulphur concentration of the zones is measurable. To isolate different transport mechanisms responsible for these element distributions UHPC samples were thermally treated at 90 °C and the microstructure was investigated under dry conditions and after immersion in water to investigate the influence of dehydration during and rehydration after the thermal treatment on the microstructure. Through durability testing via water absorption, water vapour diffusion, permeability testing and sulfuric acid resistance transport mechanisms like diffusion, migration, capillary suction are under investigation in correlation with the microstructure analysis. For the microstructure analysis measurements with µXRF, mercury intrusion porosity, XRD and SEM were conducted. T2 - HiPerMat 2020 CY - Kassel, Germany DA - 11.03.2020 KW - UHPC KW - Thermal treatment KW - Zonation KW - Transport mechanism KW - Durability PY - 2020 SN - 978-3-7376-0828-2 U6 - https://doi.org/10.17170/kobra-202002271026 VL - 23 SP - 151 EP - 152 PB - Kassel University Press CY - Kassel AN - OPUS4-52373 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - von Werder, Julia A1 - Simon, Sebastian A1 - Gardei, André A1 - Fontana, P. A1 - Meng, Birgit T1 - Thermal and hydrothermal treatment of UHPC: influence of the process parameters on the phase composition of ultra-high performance concrete N2 - Several studies show that thermal and hydrothermal treatment can further improve the excellent properties of UHPC in terms of mechanical strength and durability. While for the thermal treatment the increase in strength is attributed to an intensified pozzolanic and hydraulic reaction, for the hydrothermal treatment previous studies accredited it mostly to the formation of tobermorite. In the presented study thermal and hydrothermal treatment of UHPC samples was systematically varied and the phase formation analysed related to the strength development of a reference sample cured for 28 days in water. For the thermal treatment the results show that the strength increase depends on the protection against desiccation and can be ascribed to an improved pozzolanic reaction of the siliceous fillers. To achieve a significant enhancement of strength, a pre-storage time of few days and a long dwell time at elevated temperature/pressure are required. For the hydrothermal treatment already heating the specimens up to 185 °C in saturated steam followed by an immediate cooling leads to a substantial increase in compressive strength. Pre-storage time did not affect the result as far as a minimum of several hours is guaranteed. The improved performance is due to an increase in the pozzolanic and hydraulic reaction. Surprisingly, tobermorite was only found within a very thin layer at the surface of the sample, but not in the bulk. Sulphate and aluminium stemming from the decomposition of the ettringite are bound in the newly formed phases hydroxylellestadite and hydrogarnet. KW - UHPC KW - Thermal treatment KW - Hydrothermal treatment KW - Compressive strength KW - Phase development KW - Durability KW - Tobermorite KW - Hydroxylellestadite KW - Hydrogarnet PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-523402 SN - 1871-6873 SN - 1359-5997 VL - 54 IS - 1 SP - Article 44 PB - Springer Nature AN - OPUS4-52340 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Meng, Birgit A1 - Weise, Frank A1 - Voland, K. A1 - Krütt, Enno T1 - Ermüdungsbedingte Degradation und ihre Auswirkungen auf den Stofftransport in Fahrbahndeckenbeton N2 - Im Rahmen des Beitrags soll aufgezeigt werden, welchen Einfluss eine mechanisch induzierte Vorschädigung (Ermüdungsbeanspruchung) auf den Ablauf und die Intensität des AKR-Schädigungsprozesses hat. Dies erfordert eine ausführliche Beschreibung der vielfältigen interagierenden Schädigungs- und Transportprozesse und aufbauend eine enge Verknüpfung von Experimenten mit einer mehrskaligen Modellierung. Die experimentelle Basis bildete die mechanische Vorschädigung (Ermüdungsbeansprochung) großformatiger Balken aus einem Fahrbahndeckenbeton bei Einsatz alkaliempfindlicher Gesteinskörnungen. Aus diesen großformatigen Balken wurden nach erfolgter Ermüdungsbeanspruchung kleinformatige Probekörper gewonnen. An diesen wurde detailliert untersucht wie sich die mechanische Vorschädigung auf das Betongefüge und die daraus resultierenden Transport- und Schädigungsprozesse auswirkt. Von der mechanisch induzierten Vorschädigung bis zum AKR Schädigungsprozess sollten in diesem Kontext die Rissbildungsprozesse und der interagierende Eintrag bzw. die Auslaugung der Alkalien ganzheitlich betrachtet werden. Der Beitrag fokussiert auf die Charakterisierung der infolge der mechanischen Vorschädigung induzierten Rissbildungsprozesse. Ferner wird detailliert auf die Auswirkungen der mechanischen Rissbildung auf den Stofftransport eingegangen. KW - Baustoffe KW - Beton KW - Dauerhaftigkeit KW - Ermüdung KW - Alkali-Kieselsäure-Reaktion KW - AKR PY - 2017 SN - 978-3-00-056692-9 SP - 416 EP - 427 CY - Bochum AN - OPUS4-42970 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Wiens, U. A1 - Meng, Birgit T1 - Zur Eignung von Hochleistungsbetonen bei chemischem Angriff N2 - Ende der 1990er-Jahre beauftragte die Philipp Holzmann AG das Institut für Bauforschung der RWTH Aachen (ibac) mit der Durchführung von Untersuchungen zur Eignung von Hochleitsungsbetonen bei chemischem Angriff. Im Rahmen des Forschungsvorhabens sollte geprüft werden, inwieweit die Möglichkeit besteht, durch betontechnische Maßnahmen die Widerstandsfähigkeit des Betons zu erhöhen, wodurch evtl. erforderliche Schutzmaßnahmen entfallen können. Aus diesem Grund wurden Hochleistungsbetone mit sehr niedrigen Wasserbindemittelwerten unter Verwendung von anorganischen (Silicastaub und Steinkohlenflugasche) und organischen (Polymerdispersion auf Basis von Styrolacrylat) Betonzusatzstoffen hergestellt, in verschiedenen betonangreifende Medien (5%ige Ammoniumnitratlösung, Essigsäure (pH 3,5), sowie Müll-, Klärwasser und Sulfatläsung) eingelagert und das Ausmaß der Schädigung ermittelt. Der Beitrag fasst die bisher noch nicht veröffentlichten Ergebnisse dieser Untersuchungen zusammen. KW - Baustoffe KW - Beton KW - Dauerhaftigkeit KW - Chemischer Angriff PY - 2017 SN - 978-3-00-056692-9 SP - 458 EP - 472 CY - Bochum AN - OPUS4-42971 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stelzner, Ludwig A1 - Powierza, Bartosz A1 - Weise, Frank A1 - Oesch, Tyler A1 - Dlugosch, R. A1 - Meng, Birgit T1 - Analysis of moisture transport in unilateral-heated dense high-strength concrete N2 - Unilateral thermal exposure of concrete building components induces moisture transport processes that have a significant influence on the spalling behaviour of dense high-strength concrete (HSC). These transport processes are based on evaporation and condensation mechanisms of liquid and gaseous water in the pores as well as the chemically bound water within the concrete. The low permeability of HSC and the formation of a saturated zone within building components (also known as a moisture clog) leads to high water-vapour pressures, which contributes to explosive spalling. The formation of these pressures has already been verified by means of pore-pressure measurement techniques. In addition, the redistribution of the moisture within concrete specimens subject to unilateral thermal exposure has been demonstrated on fractured surfaces. Investigations by means of the nuclear magnetic resonance (NMR) relaxometry technique and neutron radiography have shown one-dimensional changes in moisture distribution during thermal exposure. However, none of these methods has been able to depict the moisture distribution in three dimensions (3D), so the link between pore size, concrete micro-structure and moisture content is missing. The research project presented in this paper aims to fill this gap by developing a new multi-level test methodology to characterise non-destructively the temporal course of spatial moisture distribution during unilateral thermal exposure. The procedure used during this programme included the collection of X-ray 3D-computed tomography (CT) measurements using a miniaturised specimen subjected to in-situ thermal exposure and the comparison of those CT results with the results of one-dimensional NMR-relaxometry before and after the heating process. In the first step, a mobile heating device was developed, built and tested. To simulate a unilaterally-heated construction component, a cylindrical specimen made of HSC (Ø = 40 mm, L = 100 mm) was cast into an impermeable glass ceramic shell. The ceramic shell ensured a one-dimensional moisture flux and limited the thermal expansion of the concrete. An additional high-temperature wool (HTW) insulating shell ensured a one-dimensional heat flux. The heating device, which operated using infrared radiation (IR), allowed the unilateral heating of the specimens up to 300 °C using variable heating regimes. In the second step, the mobile heating device was integrated into the CT-scanner, which enabled the collection of measurements before, during and after heating. By subtraction of successive 3D-CT images, X-ray attenuation differences could be resolved three-dimensionally in the specimen and interpreted as changes in the moisture content. Initial results show that this test methodology can monitor the 3D changes of moisture content inside the specimen during thermal exposure. It enables the researcher to visualise areas with moisture accumulation as well as dehydrated areas inside the specimen. Comparative one-dimensional NMR-relaxometry measurements confirm the results of the CT image analysis. T2 - 5th International Workshop on Concrete Spalling due to Fire Exposure CY - Boras, Sweden DA - 12.10.2017 KW - Spalling KW - Fire KW - Moisture clog KW - Moisture transport KW - HPC KW - HSC KW - X-ray CT KW - NMR KW - NDT PY - 2017 SN - 0284-5172 SP - 227 EP - 239 AN - OPUS4-42983 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wallau, Wilma A1 - Pirskawetz, Stephan A1 - Voland, K. A1 - Weise, Frank A1 - Meng, Birgit ED - De Schutter, G. ED - De Belie, N. ED - Janssens, A. ED - Van Den Bossche, N. T1 - Online monitoring of the expansion of alkali-silica reaction affected concrete prisms implemented to the accelerated concrete prism test at 60 °C N2 - The accelerated concrete prism test (ACPT-60 °C) facilitates testing of alkali-silica reactivity of aggregates within five months. Manual measurement is usually conducted to determine expansion of test specimen every 28 days. This conventional procedure gives only limited insight to expansion behaviour of ASR-affected prisms. Due to the large time intervals, expansion exceeding the critical value of 0.3 mm/m is likely to be noticed late. Continuous recording resolves this problem and delivers beneficial information on the shape of the expansion curve. Displacement transducers integrated into a special testing equipment developed at BAM put continuous measurement into practice. Additionally, ultrasonic velocity and acoustic emissions are measured in-situ and provide deeper insights into hydration and crack formation processes during the test. Aiming for an automated testing method close to the German guideline, the following technical and methodical challenges arise. Changing of the vertical orientation of the prisms with every manual measurement as standardised cannot be implemented. Furthermore, preliminary results already proved true that cooling and heating cycles, as necessarily associated with each manual measurement, can evoke additional expansion. Therefore, interrupted and continuously measured expansions reveal systematic differences, indicating the necessity to adjust the threshold expansion value for automated testing. Results presented in the paper: Different types of reactive aggregate have been tested applying continuous and manual expansion measurement to the concrete specimens. Development of continuously measured ultrasonic velocity and acoustic emissions of the aggregates tested diverge significantly while the expansion curves vary in shape and maximum strain. Prisms produced from a slowly reacting aggregate do not exhibit noticeable crack formation. It shows that comprehensive measuring helps describing and distinguishing ASR-damage mechanisms. Models of ASR-induced expansion, available in the open literature, so far are validated with discontinuous data hardly tracing the modelled curve. Continuous measurement improves validation and further model development. T2 - XIV DBMC - 14th International Conference on Durability of Building Materials and Components CY - Gent, Belgium DA - 29.05.2017 KW - Alkali-silica reaction KW - Accelerated concrete prism test KW - Continuous monitoring KW - Expansion modelling PY - 2017 SN - 978-2-35158-159-9 VL - PRO 107 SP - 1 EP - 11 PB - RILEM Publications S.A.R.L. AN - OPUS4-40499 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Selleng, Christian A1 - Fontana, Patrick A1 - Simon, Sebastian T1 - Possibilities for improving the properties of UHPC by means of thermal treatment N2 - A further improvement of the excellent properties of UHPC can be realized with thermal Treatment. Like for normal concrete, it accelerates the hardening and prevents shrinkage after the treatment. Additionally, an increase in strength can be achieved. Aim of this study was the optimisation of the thermal Treatment conditions of UHPC for very different Treatment methods; heat Treatment at 90 °C for unprotected and sealed samples, hot water bath at 90 °C and hydrothermal Treatment at 185 °C/1.1 MPa. The pre-storage time and the dwell time were systematically varied for each method to gain a higher strength. The compressive strength depends on the manner of Treatment at which higher water accessibility leads to higher strengths. The Phase composition changes considerably with different Treatment tempereatures. Finally, it can activate unhydrated binder components forming additional C-S-H, leading to higher strength. T2 - International Symposium on Ultra-High Perfomance Fibre-Reinforced Concrete UHPFRC 2017 CY - Montpellier, France DA - 02.10.2017 KW - Building Materials KW - Ultra-High Performance Concrete (UHPC) KW - Heat treatment KW - Autoclaving KW - X-ray diffraction (XRD) PY - 2017 AN - OPUS4-42570 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Giebson, C. A1 - Voland, K. A1 - Ludwig, H.-M. A1 - Meng, Birgit T1 - Alkali-silica reaction performance testing of concrete considering external alkalis and preexisting microcrack N2 - In concrete elements, simultaneously subjected to cyclic loadings and external alkalis, the risk for damage caused by or under participation of an alkali-silica reaction (ASR) is particularly high. This is of particular concern for concrete pavements due to the increasing heavy vehicle traffic and the application of sodium chloride (NaCl) de-icer during winter. Since 2004, the climate simulation concrete prism test (CS-CPT) has been used successfully to evaluate job mixtures for pavements by considering the impact of alkali-containing de-icers. However, the role of mechanical predamage on ASR is largely unclear. In a joint research project, the CS-CPT has been used to investigate the influence of preexisting microcracks on ASR. It was evident that an ASR initiated earlier in the predamaged concrete prisms due to the more rapid ingress of NaCl solution through the microcracks. KW - Alkali-silica reaction KW - Climate simulation concrete prism test KW - External alkalis KW - Laser-induced breakdown spectroscopy KW - Microcracks KW - Pavement concrete PY - 2017 U6 - https://doi.org/10.1002/suco.201600173 SN - 1464-4177 SN - 1751-7648 VL - 18 IS - 4 SP - 528 EP - 538 PB - Ernst & Sohn AN - OPUS4-42574 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Selleng, Christian A1 - Simon, Sebastian A1 - Fontana, Patrick A1 - Meng, Birgit T1 - Possibilities for improving the properties of UHPC by means of thermal treatment N2 - A further improvement of the excellent properties of UHPC can be realized with thermal Treatment. Like for normal concrete, it accelerates the hardening and prevents shrinkage after the treatment. Additionally, an increase in strength can be achieved. Aim of this study was the optimisation of the thermal Treatment conditions of UHPC for very different Treatment methods; heat Treatment at 90 °C for unprotected and sealed samples, hot water bath at 90 °C and hydrothermal Treatment at 185 °C/1.1 MPa. The pre-storage time and the dwell time were systematically varied for each method to gain a higher strength. The compressive strength depends on the manner of Treatment at which higher water accessibility leads to higher strengths. The Phase composition changes considerably with different Treatment tempereatures. Finally, it can activate unhydrated binder components forming additional C-S-H, leading to higher strength. T2 - International Symposium on Ultra-High Performance Fibre-Reinforced Concrete UHPFRC 2017 CY - Montpellier, France DA - 02.10.2017 KW - Building Materials KW - Ultra-High Performance Concrete (UHPC) KW - heat treatment KW - autoclaving KW - X-ray diffraction (XRD) PY - 2017 SN - 978-2-35158-166-7 VL - PRO 106 SP - 83 EP - 92 PB - RILEM Publications SARL CY - Paris, France AN - OPUS4-42569 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schraut, Katharina A1 - Adamczyk, Burkart A1 - Simon, Sebastian A1 - von Werder, Julia A1 - Meng, Birgit A1 - Stephan, D. A. A1 - Adam, Christian T1 - Zementklinker durch Nachbehandlung von Stahlwerksschlacken N2 - Die Klinkerphasenbildung durch Sinterung in Drehrohröfen bei der Herstellung von Portlandzementklinker (PZK) ist gründlich erforscht und optimiert. Im Hinblick auf mögliche ökonomische und ökologische Vorteile befassen sich aktuelle Forschungsvorhaben darüber hinaus mit der Herstellung von Klinkermineralen aus Stahlwerksschlacken, die eine vergleichbare chemische Zusammensetzung aufweisen. Neuste Untersuchungen zeigen, dass nach der reduzierenden Behandlung schmelzflüssiger Linz-Donawitz-(LD)-Schlacken und Abscheidung des gebildeten metallischen Eisens eine mineralische Schlacke entsteht, die unabhängig von ihren Abkühlbedingungen ca. 50–60 Gew.% des wichtigsten Klinkerminerals Alit (C3S) enthält und eine hohe hydraulische Reaktivität aufweist. Die Stabilität des Alits auch nach langsamer Abkühlung deutet auf eine Stabilisierung des Minerals durch Nebenelemente aus den LD-Schlacken hin. Ein sinkender Anteil an LD-Schlacke durch Zusatz synthetischer Schlackemischung, die sich hinsichtlich ihrer Hauptkomponenten wie eine ausreduzierte LD-Schlacke zusammensetzt, führt zu einem Rückgang des Alitgehaltes und dem Zerfall der Schlacke beim Erstarren. T2 - 5. Schlacken-Symposium CY - Meitingen, Germany DA - 25.10.2018 KW - LD-Schlacke KW - Zement KW - Tricalciumsilikat PY - 2018 SP - 219 EP - 229 PB - Max Aicher Unternehmensgruppe AN - OPUS4-46412 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - von Werder, Julia A1 - Simon, Sebastian A1 - Lehmann, C. A1 - Selleng, C. A1 - Fontana, P. A1 - Meng, Birgit T1 - Autoclaving of ultra-high performance concrete (UHPC) N2 - By the combination of an optimized granulometry, a reduced water cement ratio and the use of superplasticizers ultra-high performance concrete achieves a compressive strength of over 150 N/mm2 and a high resistance regarding acids and water-soluble salts. In different Research projects the effect of an autoclavation on the mechanical strength and the phase composition was analyzed. In systematic studies, the concrete mix and the process parameters were varied. The results show that autoclavation leads to an improved pozzolanic and hydraulic reaction and significantly improves the mechanical strength compared to a conventional thermal treatment. If a minimum time-span for hydration is ensured, the achievable strength level is not dependent on the prestorage time. However, the duration of the autoclaving is significant. After the Maximum strength is reached there is only a very slight decrease, even if unrealistically long autoclaving times are applied. T2 - ICAAC 6th International Conference on Autoclaved Aerated Concrete CY - Potsdam, Germany DA - 04.09.2018 KW - Heat treatment KW - Hydroxylellestadite KW - Tobermorite KW - Ultra-high performance concrete KW - Zonation PY - 2018 SN - 978-3-433-03276-3 U6 - https://doi.org/10.1002/cepa.866 SP - 131 EP - 136 PB - Wilhelm Ernst & Sohn - Verlag für Architektur und technische Wissenschaften GmbH & Co. KG CY - Berlin, Germanry AN - OPUS4-46357 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Breitenbücher, R. A1 - Przondziono, R. A1 - Meng, Birgit A1 - Krütt, Enno A1 - Weise, Frank T1 - Alkali-Silica Reaction in concrete pavements considering traffic and de-icing agents N2 - In concrete pavements, damages occurred which are related to an Alkali-Silica-Reaction (ASR). Although the background for such an ASR has been studied extensively, special conditions in pavements increase this reaction significantly. These are especially the superposition of microstructural degradation caused by cyclic loading with an external alkali supply. Previous investigations of ASR focused mainly on the material itself (aggregates, cements, assessment of the concrete) while these special circumstances have not been considered. Concrete pavements are subjected to cyclic loadings by traffic and climate changes. Within cooperative research projects the different interdependent influencing factors for a damaging ASR in concrete pavements are studied by experiments as well as by numeric modelling. On the micro-level the ASR-related processes within the aggregate, such as gel-formation or ion-transport, are investigated. On the meso-level, the project focuses on the characterization of degradation effects in the concrete microstructure due to cyclic loading. Further, special attention is paid to the transport behavior of fluids in such pre-damaged concrete structures with and without the effect of overrunning tires as well as the impact on the ASR itself. Finally, on the macro-level the risk of an ASR-damage is assessed. T2 - 13th International Symposium on Concrete Roads CY - Berlin, Germany DA - 19.06.2018 KW - Alkali-Silica Reaction KW - Degradation KW - Cyclic loading KW - Fluid transport KW - Traffic PY - 2018 SP - 1 EP - 15 AN - OPUS4-46354 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wiedmann, A. A1 - Weise, Frank A1 - Kotan, E. A1 - Müller, H. S. A1 - Meng, Birgit T1 - Effects of fatigue loading and alkali-silica reaction on the mechanical behaviour of pavement concrete N2 - The primary aim of this paper is to analyze the impact of mechanical pre-damage and alkali–silica reaction (ASR) on the fracture mechanical properties of pavement concrete. For this purpose, a four point bending test was applied to large format beams to produce a defined level of cyclic pre-damage. The fatigue-induced concrete degradation process was simultaneously recorded using a testing procedure specifically developed for the purpose. In addition, fatigue-induced cracks on extracted drilling cores were spatially visualized and quantified using micro X-ray 3D-computed tomography (3D-CT). The storage of the small-format test specimens, with and without cyclic pre-damage, in an ASR-conducive environment showed that pre-damage leads to an increase in ASR damage processes. Subsequent structural mechanical investigations on small format specimens with and without pre-damage show that fatigue loading and ASR significantly influence fracture mechanical parameters of the concrete. KW - Acoustic emissions analysis KW - Alkali-silica reaction KW - Concrete pavement KW - Fatigue loading KW - Fracture energy KW - Monitoring of damage KW - Tensile strength KW - Ultrasonic velocity PY - 2017 U6 - https://doi.org/10.1002/suco.201600179 SN - 1751-7648 SN - 1464-4177 VL - 18 IS - 4 SP - 539 EP - 549 PB - Ernst & Sohn AN - OPUS4-41007 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - Interactions of polysaccharide stabilising agents with early cement hydration without and in the presence of superplasticizers N2 - Polysaccharides are incorporated into cement based Systems in order to modify the rheological properties. Typically, cellulose ethers, sphingan gums, guar gum or starch ethers are applied. Depending upon their chemistry, molecular architecture, and adsorption tendency, polysaccharides interact differently with the entire cementitious system. Some stabilising agents like diutan gum mainly affect the cementitious paste; other stabilising agents like starch tend to interact with the sand fraction and even with the coarse aggregates. Cellulose and guar gum shows more diverse performances. Typically stabilising admixtures like polysaccharides are used, when sophisticated rheological properties are adjusted. Therefore, polysaccharides are often used in combination with superplasticisers, which are added to reduce the yield stress of concrete. This can cause interactions, particularly when the stabilising Agent shows a strong tendency to adsorb on particle surfaces. Adsorptive stabilising agents may reduce the amount of adsorbed superplasticisers, thus affecting both viscosity and yield stress, while non-adsorptive stabilising agents mainly affect the plastic viscosity independently of the superplasticiser. Due to the strong influence of superplasticisers on the yield stress, influences of the stabilising agent on the yield stress retreat into the background, so that their major effect is an increase of the plastic viscosity. The paper provides a comprehensive overview of how different polysaccharide superplasticisers affect cementitious flowable systems and points out the challenges of the combined use of polysaccharides and superplasticisers. Based on rheometric experiments and observations of the hydration process, time dependent effects on the workability as well as of the hydration of cement are presented and discussed. KW - Concrete KW - Polysaccharides KW - Rheology KW - Stabilising agents KW - Starch KW - Sphingan PY - 2017 U6 - https://doi.org/10.1016/j.conbuildmat.2016.11.022 SN - 0950-0618 SN - 1879-0526 VL - 139 SP - 584 EP - 593 PB - Elsevier AN - OPUS4-40597 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weise, Frank A1 - Krütt, Enno A1 - Meng, Birgit T1 - AKR unter kombinierten Einwirkungen - Rissbildungs- und Transportmechanismen N2 - Die vorstehend dargestellten Untersuchungen lassen sich wie folgt zusammenfassen: • Mit dem für die mechanische Vorschädigung entwickelten Versuchsstand und gewählten Prüfregime können die für die ermüdungsinduzierte Schadensevolution typische stabilisierende und stabile Phase in der auf Zug beanspruchten Betonrandzone gut abgebildet werden. So wurde dort zum Beispiel, ausgehend von dem hier gewählten praxisnahen Belastungsregime, mit Ultraschall in der Ruhephase durch das Trockenschwingen ein maximaler Abfall des relativen dynamischen E-Moduls von ca. 8 - 10 % ermittelt. • Mit aufbauenden kapillaren Aufsaugversuchen wurde gezeigt, dass die erzeugte Betondegradation zu einer moderaten Erhöhung der Aufnahme des Prüfmediums führt. • Zur Bewertung der Auswirkungen einer alleinigen Vorschädigung (Trockenschwingen) auf die schädigende AKR mittels Performance-Prüfung ist die Klimawechsellagerung aufgrund der einseitigen Tausalzbeaufschlagung am besten geeignet. Die hier ermittelten Dehnungsverläufe lassen auf einen moderaten Einfluss der mechanischen Vorschädigung auf die AKR schließen. • Die zusätzlich im Kontext der Nasschwingversuche durchgeführten 60°C Betonversuche zeigen, dass die zyklische Beanspruchung vor und nach dem Aufbringen der Tausalzlösung die schädigende AKR gleichfalls moderat erhöht. In derzeit laufenden ergänzenden Untersuchungen wird der separate Einfluss der ermüdungsinduzierten Rissbildung auf die schädigende AKR an homogen, stärker geschädigten Prüfkörpern mit einem hohen inneren AKR-Schädigungspotenzial im 60°C Betonversuch grundhaft analysiert. Zusätzlich wird gegenwärtig der Einfluss der degradierten Betonrandzone auf die Dehnungsverteilung an großformatigen Prüfkörpern über die Höhe im 40°C Betonversuch vertiefend für die makroskopische Modellierung untersucht. T2 - 20. Internationale Baustofftagung ibausil CY - Weimar, Germany DA - 12.09.2018 KW - Betonfahrbahndecke KW - Alkali-Kieselsäure-Reaktion KW - Tausalz KW - LIBS KW - MRFA KW - Nasschemie KW - ZfP PY - 2018 SN - 978-3-00-059950-7 SP - 1 EP - 13 AN - OPUS4-46174 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Simon, Sebastian A1 - Selleng, C. A1 - von Werder, Julia A1 - Meng, Birgit T1 - Einfluss der thermischen Behandlung auf die Phasenentwicklung und die Eigenschaften von UHPC N2 - UHPC (engl. ultra-high-performance concrete) bietet außergewöhnliche Eigenschaften, die sich durch eine optimierte Wärmebehandlung weiter verbessern lassen. Wie bei normalen Beton beschleunigt eine Wärmebehandlung den Aushärteprozess und reduziert das Schrumpfen. Durch Ausbildung eines dichteren Gefüges wird weiterhin die Druckfestigkeit und die Resistenz gegenüber Umwelteinflüssen erhöht. Die Art der Wärmebehandlung wird durch die Parameter: Temperatur, Druck, Wasserdampfsättigung und Dauer definiert und hat einen entscheiden Einfluss auf die Phasenentwicklung und damit auf die makro- und mikroskopischen Eigenschaften des UHPCs. Auch die Dauer und Art der Vorlagerung des UHPCs vor der thermischen Behandlung sind von Bedeutung. Ziel der vorgestellten Untersuchung war der Vergleich und die Optimierung verschiedener Wärmebehandlungsarten mit Blick auf die Druckfestigkeits- und Phasenentwicklung. Dafür wurden UHPC-Zylinder und Prismen hergestellt und ungeschützt bzw. in Folie eingeschweißt bei 90 °C im Ofen, im Heißwasserbad, sowie alternativ bei 185 °C und 1.1 MPa im Autoklaven wärmebehandelt. Zusätzlich wurde die Vorlagerungs- und die Behandlungszeit systematisch variiert. Die Ergebnisse zeigen, dass eine praxisnahe Wärmebehandlung im Ofen (kurze Vorlagerungs- und Behandlungszeit, Verdunstungsschutz durch Einschweißen in Folie) zwar zu einer stark erhöhten Frühfestigkeit führt, aber die Langzeitfestigkeit wird nicht signifikant erhöht. Erst längere Behandlungszeiten verbunden mit intensiviertem Schutz gegen das Austrocknen führen darüber hinaus zu deutlich erhöhten Langzeitfestigkeiten. Nach der Autoklavierung dagegen wurden Festigkeitszuwächse von bis zu 30 % gemessen. Die röntgenographisch nachgewiesene Phasenentwicklung wird in beiden Behandlungsarten durch die Limitierung des zur Verfügung stehenden Wassers bestimmt. Bei der Wärmebehandlung im Ofen wird das durch den Ettringitzerfall freigesetzte Wasser für die puzzolanische Reaktion der Mikrosilika verbraucht, reicht aber für eine weitere Reaktion der Klinkerphasen nicht aus. Bei der hydrothermalen Behandlung dagegen zeigen die Veränderungen im Phasenbestand sowohl eine Intensivierung der puzzolanischen als auch der hydraulischen Reaktion. Der für autoklavierte Baustoffe charakteristische Tobermorit konnte jedoch nicht im Probeninneren, sondern nur als Belag auf der Probenoberfläche nachgewiesen werden. Ursächlich hierfür ist vermutlich wiederum das zu geringe Wasserangebot im Gefüge des UHPC. T2 - 20. Internationale Baustofftagung ibausil CY - Weimar, Germany DA - 12.09.2018 KW - UHPC KW - Wärmebehandlung KW - Hydrothermale Behandlung KW - XRD KW - Kristalline CSH-Phase KW - Tobermorit KW - Ettringit KW - Hydroxyellestadit KW - Hydrogranat PY - 2018 SN - 978-3-00-059950-7 SP - 1 EP - 10 AN - OPUS4-46176 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krütt, Enno A1 - Weise, Frank A1 - Meng, Birgit ED - Ye, G. ED - Yuan, Y. ED - Romero Rodriguez, C. ED - Zhang, H. ED - Savija, B. T1 - Fatigue induced degradation in pavement concrete and its effect on the alkali-silica reaction N2 - In recent years the German motorway network has seen an increase in the occurrence of damage to concrete road surfaces that can be attributed to the alkali-silica reaction (ASR). In view of the often drastically reduced service life of road surfaces due to ASR, research activity in this field has notably increased. Alongside preventative measures in concrete technology i.e. the usage of low-alkali cements, the main research focus up to now has been on the development of performance-oriented testing procedures for ASR prevention. The effects of mechanicallyinduced damage resulting from cyclic traffic and climatic loading have previously not been taken into consideration. The assessment of the myriad degradation and transport processes necessary for an understanding of these effects requires close interaction between experiments and corresponding multi-scale models. This contribution is focused on the experiments utilizing innovative testing techniques. The research is founded on a series of fatigue tests performed on large-scale beams with simultaneous tracking of the degradation process using non-destructive evaluation methods. Subsequently, smaller test specimens were extracted from the predamaged beams for further experiments. These experiments included investigation of the influence of fatigue-induced cracks on moisture and alkali transport. Subsequent storage of the small-scale test specimens, with and without cyclic pre-damage, in an ASR-conducive environment then provided initial findings on the influence of fatigue-induced degradation on the ASR. The results show that the degradation process can be well observed with the test Setup developed for the fatigue experiments. Further, a small but noticeable increase of mass Transport due to fatigue-induced degradation was measured, which correspondingly indicated an increased ASR damage potential. T2 - 4th International Conference on Service Life Design for Infrastructures (SLD4) CY - Delft, The Netherlands DA - 27.08.2018 KW - Fatigue KW - Pavement KW - ASR KW - Concrete PY - 2018 SN - 978-2-35158-213-8 SP - 112 EP - 121 PB - RILEM Publication S.A.R.L. CY - Paris, France AN - OPUS4-46197 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Miccoli, L. A1 - Fontana, P. A1 - Qvaesching, D. A1 - Kreft, O. A1 - Hoppe, Johannes A1 - Meng, Birgit T1 - UHPC-AAC facade elements: Structural design, production technology and mechanical behavior N2 - The aim of this study was to develop a lightweight composite facade element for new buildings and for the refurbishment of existing facades. These composite elements have been developed combining an insulation layer of autoclaved aerated concrete (AAC) with an external ultrahighperformance concrete (UHPC) supporting layer. This solution allows avoiding the use of connectors and facilitates the production procedure. The structural behavior of the facade elements is mainly influenced by the presence of the upturning edges that are able to increase the stiffness of the element and reduce the thickness of the external layer. The insulation material has no influence on the structural behavior of the UHPC boxes. Flexural tests were carried out to investigate a potential detachment of the external layer from the upturning edge. The photogrammetric Analysis used during the flexural tests essentially confirmed that the bond between the two UHPC layers cast in two steps is reliable. The quality of the bond between the external layer and the upturning edge is a key parameter to define the bearing capacity of the element. T2 - ICAAC 6th International Conference on Autoclaved Aerated Concrete CY - Potsdam, Germany DA - 04.09.2018 KW - Autoclaved aerated concrete KW - Flexural testing KW - Photogrammetric analysis KW - Production technology KW - Ultrahigh-performance concrete PY - 2018 SN - 978-3-433-03276-3 U6 - https://doi.org/10.1002/cepa.854 VL - 2 IS - 4 SP - 483 EP - 488 PB - Wilhelm Ernst & Sohn - Verlag für Architektur und technische Wissenschaften GmbH & Co. KG CY - Berlin, Germany AN - OPUS4-47588 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Voigt, Marieke A1 - Gardei, Andre A1 - Meng, Birgit ED - di Prisco, M. ED - Meda, A. ED - Balazs, G.L. T1 - The adaption of the set-up for gas permeability measurements for ultra-high performance concrete N2 - In the framework of this project, a steam pressure vessel was to be developed from ultra-high perfor-mance concrete (UHPC) to withstand process temperatures of 200 °C and the respective steam pressure of 15,5 bar. To guarantee the long-term water vapour tightness of the system, the permeability of two UHPC mixtures were tested after long-term cyclic autoclaving. As UPHC shows a high density and therefore low permeability, measurements after the RILEM-Recommendation (TC 116-PCD) reached their detection limit. Therefore, the measurement set-up was adapted to measure the permeability of highly dense UHPC more reliably and quickly. This adaption includes measurements in a higher pres-sure range, the change of sample size thickness and the usage of Ar as a medium compared with the RILEM Recommendation. Additionally, the system was equipped with two pressure sensors and Ar-flowmeters to guarantee a continuous record of the experimental parameters. The new system was tested and evaluated by comparing measurements with the RILEM recommended system. Preliminary results show that the adapted system is capable to provide efficient and reliable results of concrete with low permeability. T2 - 14th fib PhD Symposium in Civil Engineering CY - Rom, Italy DA - 05.09.2022 KW - Durability KW - UHPC KW - gas permeability PY - 2022 SN - 978-2-940643-17-2 SN - 2617-4820 VL - 58 SP - 353 EP - 359 AN - OPUS4-56862 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stohl, Leonie A1 - Manninger, Tanja A1 - von Werder, Julia A1 - Dehn, F. A1 - Gorbushina, Anna A1 - Meng, Birgit T1 - Bioreceptivity of concrete - A review N2 - Materials that support natural biodiversity on their surfaces can compensate for human activities that have a negative impact on nature and thus contribute to a carbon-neutral and nature-positive world. Specifically designing bioreceptive materials which favor the growth of biofilms on their surface is an approach complementing conventional, macroscopic green façades. But what exactly characterizes a bioreceptive substrate and how do biofilm and substrate interact? How and why does a spontaneous colonization and the formation of biofilms take place? What are biofilms and how can they be established in a laboratory setting? How can this existing knowledge be transferred to the artificial stone concrete so that this material can be tuned to increase (or decrease) its bioreceptivity? This review paper aims at summarizing the existing state of knowledge on bioreceptive concrete and pointing out inconsistencies and contradictions which can only be removed by more interdisciplinary research in the field. KW - Bioreceptivity KW - Biofilm KW - Green facades KW - Developing building materials KW - Surface interactions KW - Concrete PY - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-581685 SN - 2352-7102 VL - 76 SP - 1 EP - 17 PB - Elsevier AN - OPUS4-58168 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Dehn, F. A1 - Unger, Jörg F. A1 - Shepherd, D. A. A1 - Tamsen, Erik A1 - Pirskawetz, Stephan T1 - Wissensbasierte Digitalisierung von betontechnologischen Materialdaten N2 - Die sprunghaft zunehmende Wichtigkeit von FAIR- und Open-Data für die Qualitätssicherung, aber auch für die Nachnutzbarkeit von Daten und den Erkenntnisfortschritt führt zu enormem Flandlungsbedarf in Forschung und Entwicklung. Damit verbunden laufen derzeit vielfältige, ambitionierte Aktionen, z. B. bezüglich der Erstellung von Ontologien und Wissensgraphen. Das Knowhow entwickelt sich rasant, die Ansätze zur Implementation entstehen in verschiedenen Fachwelten bzw. mit unterschiedlichen Zielsetzungen parallel, so dass recht heterogene Herangehensweisen resultieren. Diese Veröffentlichung fokussiert auf Arbeiten, die derzeit als möglichst ganzheitlicher Ansatz für Materialdaten im Rahmen der Digitalisierungsinitiative „Plattform MaterialDigital" vorangetrieben werden. Die Autoren bearbeiten baustoffbezogene Aspekte im Verbundprojekt „LeBeDigital - Lebenszyklus von Beton". Zielsetzung ist die digitale Beschreibung des Materialverhaltens von Beton über den kompletten Herstellungsprozess eines Fertigteils mit einer Integration von Daten und Modellen innerhalb eines Workflows zur probabilistischen Material- und Prozessoptimierung. Es wird über die Vorgehensweise und die dabei gewonnenen Erfahrungen berichtet, nicht ohne den Blick auf die oft unterschätzte Komplexität der Thematik zu lenken. T2 - Internationale Baustofftagung (ibausil) CY - Weimar, Germany DA - 13.09.2023 KW - Beton KW - Digitalisierung KW - Materialdaten KW - Datenmanagement KW - FAIR-Prinzip KW - Metadaten KW - Ontologie KW - Wissengraph PY - 2023 UR - https://www.uni-weimar.de/de/bauingenieurwesen/institute/fib/ibausil/ VL - 2023 SP - 1 EP - 11 PB - Sonderausgabe des Online-Journals ce/papers von Wiley AN - OPUS4-58315 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hirsch, T. A1 - Voigt, Marieke A1 - Lehmann, Christian A1 - Meng, Birgit A1 - Lothenbach, B. T1 - Impact of autoclaving on the phase assemblage of Portland cement: Experiment and thermodynamic modelling N2 - Even after autoclaving for 2 weeks in the temperature range of 120 to 200 °C, CEM I paste with a water-to-cement ratio of 0.5 still contains some low-crystalline C-S-H. The conversion of low-crystalline C-S-H to crystalline is faster with increasing temperature. The observed low-crystalline and crystalline C-S-H phases (reinhardbraunsite, jaffeite) indicate that the sampleshave not reached equilibrium yet under these experimental conditions. However, there is a good agreement between experiment and thermodynamic modelling for the other solids indicating that the used datasets are suitable for this application. T2 - 16th International Congress on the Chemistry of cement 2023 - ICCC2023 CY - Bangkok, Thailand DA - 18.09.2023 KW - Zement KW - Thermodynamik KW - Phasenzusammensetzung KW - Mineralogie KW - Modellierung PY - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-589779 UR - https://iccc2023.org VL - 1 SP - 619 EP - 621 AN - OPUS4-58977 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schraut, Katharina A1 - Adamczyk, Burkart A1 - Adam, Christian A1 - Stephan, Dietmar A1 - Meng, Birgit A1 - Simon, Sebastian A1 - von Werder, Julia A1 - Hirsch, Tamino A1 - Manninger, Tanja T1 - Effect of gypsum on the hydration of fused cement clinker from basic oxygen furnace slag N2 - Fused cement clinker can be produced from molten basic oxygen furnace slag (BOFS) by way of a reductive thermochemical treatment. During the thermochemical treatment, oxidic iron is reduced to metallic iron and separated. The resulting low-iron slag has a chemical and mineralogical composition similar to ordinary Portland cement (OPC) clinker. In this study, the hydraulic reactivity of the fused clinker from BOFS with and without gypsum was investigated using isothermal calorimetry, differential scanning calorimetry, in situ X-ray diffraction and powder X-ray diffraction. Furthermore, a synthetic fused clinker without foreign ions and fused clinker produced by a mixture of both materials was studied. The hydraulic reaction of the fused clinker from BOFS was considerably slower than that of OPC. However, the reaction can be accelerated by adding gypsum as a sulfate carrier. Furthermore, the results showed an increased reaction rate with decreasing content of foreign ions such as Fe, P or Mn. KW - General Materials Science KW - Building and Construction PY - 2024 U6 - https://doi.org/10.1680/jadcr.23.00070 SN - 0951-7197 SP - 1 EP - 19 PB - Telford AN - OPUS4-59391 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Hauer, B. A1 - Pierkes, R. A1 - Schäfer, S. A1 - Seidel, M. A1 - Herbst, Tristan A1 - Rübner, Katrin A1 - Meng, Birgit T1 - Verbundforschungsvorhaben 'Nachhaltig Bauen mit Beton' - Potenziale des Sekundärstoffeinsatzes im Betonbau - Teilprojekt B N2 - Die Nutzung und Weiterverarbeitung von Sekundärstoffen kann in der Baustoffherstellung einen Beitrag zum nachhaltigen Bauen leisten. Im Rahmen des Teilprojekts B wurde die Bewertung dieser Potenziale anhand von Beispielen ausgebaut und verifiziert. Die Basis dieser Bewertungsgrundlage ist die Erfüllung der grundlegenden technischen Anforderungen (ökobilanzielle Indikatoren, vergleichende ökobilanzielle Betrachtung). Im Teilprojekt E geht es um die Freisetzung umweltrelevanter Stoffe aus zementgebundenen Baustoffen. Überprüft werden sollte die Übereinstimmung zwischen Laborergebnissen, Modellierungen und realen Grundwasserkonzentrationen. Es wurden Schlitzwände errichtet, die in den Grundwasserleiter einbinden und umweltrelevante Parameter bestimmt. Grundsätzlich hat sich selbst bei Großbaustellen nur eine geringe Beeinflussung der Grundwasserqualität durch Beton ergeben. KW - Sekundärstoff KW - Zement KW - Beton KW - Nachhaltigkeit KW - Bewertung KW - Recycling KW - Betonbrechsand KW - Müllverbrennungsasche KW - Kesselsand KW - Ökobilanz PY - 2011 SN - 978-3-410-65094-2 SN - 0171-7197 IS - 584 SP - 1 EP - 151 PB - Beuth CY - Berlin AN - OPUS4-25982 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit A1 - Pirskawetz, Stephan A1 - Tamsen, Eric A1 - Unger, Jörg F. T1 - Betondesign digital - Potenziale für das Bauwesen N2 - Beton ist weltweit einer der wichtigsten Konstruktionswerkstoffe und zeichnet sich durch eine enorme Anpassungsfähigkeit an sich verändernde Anforderungen aus. Damit verbunden ist eine hohe und kontinuierlich zunehmende Komplexität hinsichtlich der Ausgangsstoffe, Rezepturen und des Herstellungsprozesses. Folglich setzt eine Ausschöpfung des technischen und umweltbezogenen Potenzials der Betonbauweise höchste Expertise bei den Einzelakteuren der Bauindustrie voraus. T2 - MatFo2022 „Vom Material zur Innovation: Digital, Neutral, Vital“ CY - Cologne, Germany DA - 14.11.2022 KW - Beton KW - Zement KW - Digitalisierung KW - Ontologien PY - 2022 UR - https://www.werkstofftechnologien.de/veranstaltungen/matfo2022-vom-material-zur-innovation-digital-neutral-vital AN - OPUS4-59140 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -