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 - RPRT A1 - C., K. A1 - van Doormaal, A. A1 - Haberacker, C. A1 - Hüsken, Götz A1 - Larcher, M. A1 - Saarenheimo, A. A1 - Solomos, G. A1 - Stolz, A. A1 - Thamie, L. A1 - Bedon, C. T1 - Numerical simulations for classification of blast loaded laminated glass: possibilities, limitations and recommendations N2 - It is important to protect critical buildings (shopping centres, government buildings and embassies), infrastructure and utilities, train and underground stations against being damaged, destroyed or disrupted by deliberate acts of terrorism, criminal activity and malicious behaviour. Normal regulations and building guidelines do not generally take into account these threats. The introduction of appropriate regulations or guidelines, where deemed necessary, should, enhance the resilience of buildings and infrastructure against explosion incidents. In order to protect the built infrastructure, methods are required to quantify the resistance of structural components against explosive loading and to assess the hazards resulting from the failure of an element. The applicable state-of-the-art techniques may include either experimental or numerical methods, or a combination of both. Therefore, the thematic group (TG) on the resistance of structures to explosion effects was formed in order to bring the required expertise together, make it commonly available and to find and define harmonised methods and solutions which can be provided to the decision-makers responsible for critical infrastructure protection. The current report summarizes existing best practices for the numerical finite element modelling of blast loading, including the important topics of domain discretisation, implicit/explicit formulation, Lagrangian/Eulerian solvers, the mathematical description of the material behaviour etc. Furthermore recommendations for the modelling of laminated glass elements are formulated and knowledge gaps in this application area are pointed out. Hence the report builds the basis for an actual evaluation of the different numerical methods, their suitability to certain problems, and their capability to support/complement the experimental testing of glass components. It thus provides helpful information to design architects and engineers, and more generally to critical infrastructure stakeholders, responsible for the structural integrity and security of the infrastructure in case of an explosion. KW - building industry KW - explosive KW - accident prevention KW - glass industry KW - industrial infrastructure KW - risk prevention KW - urban infrastructure KW - terrorism KW - technical standard KW - research report PY - 2014 SN - 978-92-79-46172-9 DO - https://doi.org/doi:10.2788/083832 SN - 1831-9424 SP - 1 EP - 39 AN - OPUS4-36908 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Bedon, C. A1 - C., K. A1 - van Doormaal, A. A1 - Haberacker, C. A1 - Hüsken, Götz A1 - Larcher, M. A1 - Saarenheimo, A. A1 - Solomos, G. A1 - Stolz, A. A1 - Thamie, L. A1 - Valsamos, G. T1 - A comparison of existing standards for testing blast resistant glazing and windows N2 - It is important to protect critical buildings (shopping centres, government buildings and embassies), infrastructure and utilities, train and underground stations against being damaged, destroyed or disrupted by deliberate acts of terrorism, criminal activity and malicious behaviour. Normal regulations and building guidelines do not generally take into account these threats. The introduction of appropriate regulations or guidelines, where deemed necessary, should enhance the resilience of buildings and infrastructure against explosion incidents. In order to protect the built infrastructure, methods are required to quantify the resistance of structural components against explosive loading and to assess the hazards resulting from the failure of an element. The applicable state-of-the-art techniques may include either experimental or numerical methods, or a combination of both. Therefore, the thematic group (TG) on the resistance of structures to explosion effects was formed in order to bring the required expertise together, make it commonly available and to find and define harmonised methods and solutions which can be provided to the decision-makers responsible for critical infrastructure protection. This report discusses the differences between the existing standards for testing blast-resistant glazing and windows and it presents basic recommendations for the future development of the suite of European standards in this area. KW - Building industry KW - Accident prevention KW - Glass industry KW - Explosive KW - Industrial infrastructure KW - Risk prevention KW - Urban infrastructure KW - Terrorism KW - Safety standard KW - Technical standard KW - Research report PY - 2014 SN - 978-92-79-46168-2 DO - https://doi.org/10.2788/361383 SN - 1831-9424 VL - JRC94930 SP - 1 EP - 42 AN - OPUS4-36904 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Bedon, C. A1 - C., K. A1 - van Doormaal, A. A1 - Haberacker, C. A1 - Hüsken, Götz A1 - Larcher, M. A1 - Millon, O. A1 - Saarenheimo, A. A1 - Solomos, G. A1 - Stolz, A. A1 - Thamie, L. A1 - Valsamos, G. A1 - Williams, A. T1 - Recommendations for the improvement of existing European norms for testing the resistance of windows and glazed facades to explosive effects N2 - It is important to protect critical buildings (shopping centres, government buildings and embassies), infrastructure and utilities, train and underground stations from being damaged, destroyed or disrupted by deliberate acts of terrorism, criminal activity and malicious behaviour. Normal regulations and building guidelines do not generally take into account these threats. The introduction of appropriate regulations or guidelines, where deemed necessary, should enhance the resilience of buildings and infrastructures against explosion incidents. In order to protect the built infrastructure, testing methods are required which can answer the question whether certain building elements can withstand certain loading conditions created by an explosive event. The applicable state-of-the-art techniques may include either experimental or numerical methods, or a combination of both. Therefore, the thematic group (TG) on the resistance of structures to explosion effects was formed in order to bring the required expertise together, to make it commonly available and to find and define harmonised methods and solutions which can be provided to the decision-makers responsible for critical infrastructure protection. The TG described in a fist report JPC87202 the physical phenomena which have to be understood in order to ensure a proper testing of the elements and a correct interpretation of the results. In a second step, the differences between the existing standards for testing blast-resistant glazing and windows have been derived, and a basis for fundamental recommendations for the future development of the suite of European standards has been addressed JRC94930. Based on the prior findings, this report now formulates the proper enhancements of the existing standards in terms of actual recommendations for the improvement of the test standards. KW - building industry KW - accident prevention KW - glass industry KW - explosive KW - industrial infrastructure KW - safety standard KW - technical standard KW - urban infrastructure KW - terrorism KW - research report PY - 2015 SN - 978-92-79-53394-5 DO - https://doi.org/doi:10.2788/319252 SN - 1831-9424 SP - 1 EP - 42 AN - OPUS4-36910 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Bedon, C. A1 - C., K. A1 - van Doormaal, A. A1 - Haberacker, C. A1 - Hüsken, Götz A1 - Larcher, M. A1 - Millon, O. A1 - Saarenheimo, A. A1 - Solomos, G. A1 - Stolz, A. A1 - Thamie, L. A1 - Valsamos, G. A1 - Williams, A. T1 - A set of essential requirements towards standardising the numerical simulation of blast-loaded windows and facades N2 - The determination of the blast protection level of laminated glass windows and facades is of crucial importance, and it is normally done by using experimental investigations. In recent years numerical methods have become much more powerful also with respect to this kind of application. This report attempts to give a first idea of a possible standardisation concerning such numerical simulations. Attention is drawn to the representation of the blast loading and of the behaviour of the material of the mentioned products, to the geometrical meshing, as well as to the modelling of the connections of the glass components to the main structure. The need to validate the numerical models against reliable experimental data, some of which are indicated, is underlined. KW - building industry KW - accident prevention KW - glass industry KW - explosive KW - industrial infrastructure KW - risk prevention KW - urban infrastructure KW - safety standard KW - technical standard KW - simulation KW - research report PY - 2015 SN - 978-92-79-57507-5 DO - https://doi.org/doi:10.2788/684747 SN - 1831-9424 SP - 1 EP - 25 AN - OPUS4-36909 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Babski, Veronika A1 - Hüsken, Götz A1 - Pirskawetz, Stephan A1 - Ehlers, Noah A1 - Kühne, Hans-Carsten A1 - Brouwers, H.J.H. ED - Fehling, E. ED - Middendorf, B. ED - Thiemicke, J. T1 - Characterisation of Ultra-High Performance Fibre Reinforced Concrete (UHPFC) under tensile loading by acoustic emission and optical deformation analysis N2 - During the past 20 years, innovative developments in concrete technology have enabled the production of ultra-high performance fibre reinforced concretes (UHPFC) for the protection and preservation of concrete structures. The main characteristics of UHPFC comprise high compressive and flexural strength as well as high ductility compared to normal strength, normal weight concrete (NSC). This paper focuses on the analysis of crack formation and crack propagation in UHPFC under tensile loading under quasistatic conditions by using acoustic emission (AE) and optical deformation analysis (ODA). AE is a non-destructive technique to monitor the development of micro structural damage processes caused by external forces. In this context, AE allows for a continuous monitoring of changes in the microstructure (cracks) over time and the corresponding localisation by appropriate algorithms. The AE measurements were performed along with ODA at the surface of the samples in order to analyse the deformation behaviour of the samples and the crack propagation. For the tests, a UHPFC reference mixture was developed and tested with three different volume percentages of steel fibres (1.0 V.-%, 2.0 V.-%, and 3.0 V.-%). This paper shows that the application of AE is a suitable method to analyse the crack propagation in UHPFC specimens under tensile loading and to localise the crack initiation. Furthermore, insights into the failure mechanism of the fibres are offered by the analysis of the signals of the AE measurements, which allows for a better understanding of UHPFC and its general performance. T2 - 4th International Symposium on Ultra-High Performance Concrete and High Performance Materials (HiPerMat) CY - Kassel, Germany DA - 09.03.2016 KW - UHPFC KW - Tensile loading KW - Acoustic emission KW - Crack formation KW - Optical deformation analysis KW - Crack propagation PY - 2016 SN - 978-3-7376-0094-1 SP - 1 EP - 9 PB - Kassel University Press CY - Kassel AN - OPUS4-36893 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Babski, Veronika T1 - Characterisation of Ultra-High Performance Fibre Reinforced Concrete (UHPFC) under Tensile Loading by Acoustic Emission and Optical Deformation Analysis N2 - During the past 20 years, innovative developments in concrete technology have enabled the production of ultra-high performance fibre reinforced concretes (UHPFC) for the protection and preservation of concrete structures. The main characteristics of UHPFC comprise high compressive and flexural strength as well as high ductility compared to normal strength, normal weight concrete (NSC). This paper focuses on the analysis of crack formation and crack propagation in UHPFC under tensile loading under quasistatic conditions by using acoustic emission (AE) and optical deformation analysis (ODA). AE is a non-destructive technique to monitor the development of micro structural damage processes caused by external forces. In this context, AE allows for a continuous monitoring of changes in the microstructure (cracks) over time and the corresponding localisation by appropriate algorithms. The AE measurements were performed along with ODA at the surface of the samples in order to analyse the deformation behaviour of the samples and the crack propagation. For the tests, a UHPFC reference mixture was developed and tested with three different volume percentages of steel fibres (1.0 V.-%, 2.0 V.-%, and 3.0 V.-%). This paper shows that the application of AE is a suitable method to analyse the crack propagation in UHPFC specimens under tensile loading and to localise the crack initiation. Furthermore, insights into the failure mechanism of the fibres are offered by the analysis of the signals of the AE measurements, which allows for a better understanding of UHPFC and its general performance. T2 - 4th International Symposium on Ultra-High Performance Concrete and High Performance Materials (HiPerMat) CY - Kassel, Germany DA - 09.03.2016 KW - Acoustic emission KW - Crack formation KW - Crack propagation KW - Optical deformation analysis KW - Tensile loading KW - UHPFC PY - 2016 AN - OPUS4-36898 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weise, Frank T1 - Influence of aggregate size on the damage potential of alkal-silica-reaction N2 - The poster shows new results on Alkali-Silica-Reaction (a damage mechanism of concrete). The influence of the aggregate size in the sand fraction is investigated, revealing that different types of aggregate behave in a different way. T2 - 15th International Conference of Alkali Aggregate Reaction in Concrete (ICAAR 2016) CY - Sao Paulo, Brazil DA - 03.07.2016 KW - Alkali-silica-reaction KW - Building materials KW - Concrete KW - Durability PY - 2016 AN - OPUS4-36951 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weise, Frank T1 - Influence of simultaneous cyclic loading and external alkali supply on the alkali-silica reaction in concrete pavements N2 - In recent years the German highway network has seen an increase in the occurrence of damage in concrete road surfaces which can be attributed to the alkali-silica reaction (ASR). In view of the often drastic reduction in life expectancy experienced by concrete pavements due to ASR, research activity in this field has notably increased. Until now the main research focus has been, alongside preventative measures in concrete technology, the development of performance-oriented testing procedures for ASR prevention. This included more specifically the accelerated simulation of climatic effects and external alkali supply on concrete pavements. The effects of pre-damage from the additionally interacting cyclic traffic loading had previously not been taken into consideration. Since 2011, a five-partner research group from the German Research Foundation has been pursuing research on the effects of simultaneous cyclic loading and external alkali supply on the destructive ASR in concrete pavements. The depiction of the myriad degradation and transport processes necessary for an understanding of these effects requires a close interaction between experiments and their multi-scale modelling. This contribution 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 NaCl solution, with simultaneous tracking of crack development. Thereafter, smaller test specimens were extracted from the pre-damaged beams for further experiments. These included the spatial visualization and quantification of fatigue-induced cracks with X-ray 3D-computed tomography. Additionally, the effects of fatigue-induced cracks on moisture and alkali transport were investigated using 3D-CT and Laser-Induced Breakdown Spectroscopy (LIBS). Subsequent storage of the small-format test specimens, with and without cyclic pre-damage, in an ASR-conducive environment was then able to shed light on the influence of fatigue-induced pre-damage 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 AN - OPUS4-36950 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Curosu, I. A1 - Pirskawetz, Stephan A1 - Mechtcherine, V. ED - Saouma, V. ED - Bolander, J. ED - Landis, E. T1 - Characterizing the crack development in strain-hardening cement-based composites (SHCC) by means of acoustic emission N2 - The article at hand presents an investigation on crack development in three different types of strain-hardening cement-based composites (SHCC) subjected to uni-axial tensile loading. The aim of the work was to evaluate the applicability of acoustic emission (AE) measurements for determining the progressive damage within the material, as well as for differentiating the individual damage events by their origin and decisive mechanisms, such as matrix cracking, fiber pullout or fiber rupture. The acoustic emission method proved to be fully appropriate for recording and evaluating the fracture related processes in various types of SHCC. Valuable information on failure mechanisms and quantitative description of damage depending on SHCC composition was obtained and evaluated with respect to the measured stress-displacement curves and under consideration of fracture surfaces and crack patterns observed on the specimens. T2 - 9th International Conference on Fracture Mechanics of Concrete and Concrete Structures CY - Berkeley,California, USA DA - 29.05.2016 KW - Building Materials KW - SHCC KW - Fiber KW - Tension KW - Fracture KW - Acoustic Emission PY - 2016 DO - https://doi.org/10.21012/FC9.207 SP - 1 EP - 10 AN - OPUS4-37199 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bartholmai, Matthias A1 - Johann, Sergej A1 - Kammermeier, Michael A1 - Müller, Maximilian A1 - Strangfeld, Christoph T1 - RFID sensor systems embedded in concrete – systematical investigation of the transmission characteristics N2 - Long-term completely embedded sensor systems offer innovative possibilities for structural health monitoring of concrete structures. Measuring of relevant parameters, e.g., temperature, humidity, or indication of corrosion can be performed with low energy sensors. This allows to implement passive RFID sensor systems without cable connection and battery, which are power supplied exclusively by the electromagnetic field from the external reader device. To evaluate characteristics and conditions of this concept, a systematical investigation of the transmission characteristics with variation of relevant parameters, as communication frequency, installation depth, type of concrete, moisture content, etc. is currently carried out in an interdisciplinary research project at BAM. First results are presented in this paper. T2 - 8th European Workshop On Structural Health Monitoring CY - Bilbao, Spain DA - 05.07.2016 KW - Structural health monitoring KW - Embedded sensor KW - Energy harvesting KW - Wireless sensors KW - RFID sensors KW - Transmission characteristics PY - 2016 SP - 1 EP - 5 AN - OPUS4-37129 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Recknagel, Christoph A1 - Alte-Teigeler, R. A1 - Bergmann, F.-J. A1 - Gebhards, G. A1 - Grabe, W. A1 - Guse, J. A1 - Hartel, S. A1 - Huth, P. A1 - Jannicke, B. A1 - Lobach, T. A1 - Schneider, T. A1 - Sondermann, E. A1 - Vengels, D. A1 - Voß, M. A1 - Willand, E. ED - Roßbach, W. T1 - Zusätzliche Technische Vertragsbedingungen und Richtlinien für Fugen in Verkehrsflächen ZTV Fug-StB 15 N2 - Unter Berücksichtigung praktischer und wissenschaftlich-technischer Erkenntnisse der letzten 15 Jahre - insbesondere auch auf der Basis verschiedener BAM-Forschungsergebnisse und Zulassungsverfahren - erfolgte eine Überarbeitung der Grundlagen, Bauprinzipien, Ausführungs- und Einbaukriterien sowie der Zulassungs- und Gütesicherungsmaßnahmen für insgesamt 4 Bauarten von Fugenfüllsystemen für hochbeanspruchte Verkehrsflächen. In diesem - für den Bundesfernstraßenbereich verbindlichen bautechnischen Regelwerk - finden insbesondere auch die Ergebnisse mehrerer wissenschaftlicher Vorhaben der BAM bezüglich labortechnischer Untersuchungen und Felduntersuchungen zum Funktionsverhalten und zur Dauerhaftigkeit erste baurechtliche Konsequenzen. Auf der Basis von Untersuchungen u.a. im Brückenbau wurden Regelungen für die Fugenausbildung in Asphalt und bei Befestigungskombinationen erarbeitet und umgesetzt. Damit konnten umfassende Regelungen für die maßgebenden Fahrbahnbeläge im Bundesfernstraßenbereich der Straßenbauverwaltung und ausführenden Industrieunternehmungen zur Verfügung gestellt werden. Die Neufassung dieser Regelungen dient darüber hinaus dem Ziel, den von der BAM vertretenen Wechsel hin zu einer performance-bezogenen Bewertungsmethodik, vorzubereiten. KW - Baustoffe KW - Fugen KW - Betonstraßen PY - 2015 SN - 978-3-86446-162-0 SP - 1 EP - 50 PB - FGSV Verlag GmbH CY - Köln AN - OPUS4-37220 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Recknagel, Christoph T1 - Was müssen flexible Fahrbahnübergänge leisten? N2 - Fahrbahnübergänge sind das bautechnisch-konstruktive Verbindungsglied von der Fahrbahn der freien Strecke auf Ingenieurbauwerke und anschließend wieder zurück auf die freie Strecke. Sowohl aus ökonomischen (Baukosten), ökologischen (Lärmschutz) als auch aus verkehrssicherheitstechnischen Gründen wurden in jüngster Zeit sogenannte flexible belagsähnliche Übergangskonstruktionen entwickelt. Der Beitrag benennt die materialtechnischen und konstruktiven Anforderungen als notwendige Grundlage für den Nachweis der Funktionsfähigkeit unter höchsten Verkehrsbeanspruchungen. Gleichzeitig werden neuartige material- und leistungsidentifizierende Kennwerte vorgestellt und deren Einfluss auf Funktionsfähigkeit und Dauerhaftigkeit diskutiert. Als versuchstechnische Grundlagen kommen durch die BAM entwickelte bzw. adaptierte Untersuchungsmethoden zur Anwendung. Die Interpretation der Untersuchungsergebnisse und deren Beitrag und Bedeutung für qualitätssichere europäische bzw. nationale Bauprodukte werden der Zielgruppe Verkehrsplanern, Straßenbaubehörden, Ausführenden und Nutzern erläutert. Schlussfolgerungen aus den veränderten baurechtlichen Rahmenbedingungen und Erfahrungen der BAM bei der europäischen Zulassung von Übergangskonstruktionen werden vorgestellt. T2 - Ingenieursymposium der Straßenbauingenieure Kanton Bern, Schweiz CY - Bern, Switzerland DA - 18.03.2016 KW - Dehnfugensysteme KW - Innovative lärmarme Übergangskonstruktionen PY - 2016 AN - OPUS4-37119 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hüsken, Götz A1 - Pirskawetz, Stephan A1 - Meinel, Dietmar A1 - Babski, Veronika A1 - Kühne, Hans-Carsten T1 - Methoden zur Analyse des Bruchverhaltens hochfester Stahlfaserbetone N2 - Hochfeste und ultrahochfeste Stahlfaserbetone eignen sich aufgrund ihrer Eigenschaften für den Einsatz bei extremen mechanischen Beanspruchungen. Das für diesen Einsatz erforderliche duktile Bruchverhalten unter Zugbeanspruchung wird ausschließlich durch die Zugabe von geeigneten Stahlfasern und deren Wirkung in der Zementsteinmatrix erreicht. Für eine gezielte stoffliche Optimierung des Systems sind fundierte Kenntnisse zur Wirkungsweise der Stahlfasern notwendig, die bei bisherigen Untersuchungen lediglich auf Basis von klassischen Messverfahren zerstörender Prüfungen gewonnen wurden. Durch das Einbeziehen von Methoden der zerstörungsfreien Materialcharakterisierung können das Bruchverhalten hochfester und ultrahochfester Stahlfaserbetone orts- und zeitaufgelöst untersucht und die einzelnen Phasen des Schädigungsprozesses identifiziert werden. Anhand der vorliegenden Ergebnisse von Zugversuchen eines ultrahochfesten Stahlfaserbetons wird der kombinierte Einsatz von Methoden der zerstörungsfreien Materialprüfung gezeigt und deren Anwendbarkeit in der Analyse des Bruchverhaltens diskutiert. Das Hauptaugenmerk liegt dabei auf der Charakterisierung der ausschlaggebenden Versagensmodi unter Zugbelastung durch die einzelnen Verfahren und dem Vergleich zu klassischen Messmethoden (z. B. Extensometer). Die Zugversuche wurden dazu parallel durch optische Verformungsanalyse mittels Bildkorrelation (DIC), Schallemissionsanalyse (SEA) und 3-D-Computertomografie (CT) begleitet. KW - Stahlfaserbeton KW - Zugbeanspruchung KW - Optische Verformungsanalyse KW - Schallemission KW - Computertomografie PY - 2016 DO - https://doi.org/10.1002/bate.201600056 SN - 1437-0999 VL - 93 IS - 10 SP - 711 EP - 716 PB - Ernst & Sohn CY - Berlin AN - OPUS4-37767 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hüsken, Götz T1 - Bewertung und Lebensdauerprognose von Brückenbauwerken – Grundlagenuntersuchungen zur Zustandsüberwachung mittels zerstörungsfreier Prüftechniken N2 - Anhand der aus Biegeversuchen vorliegenden Ergebnisse wird der Einsatz unterschiedlicher Methoden der zerstörungsfreien Materialprüfung gezeigt und deren Anwendbarkeit für die Analyse des Verformungsverhaltens von Stahlbetonbalken diskutiert. Hierzu wurde das Verformungsverhalten eines Stahlbetonbalken (L = 2,75 m) in einem 4-Punkt-Biegeversuch untersucht. Das Hauptaugenmerk liegt dabei auf der Charakterisierung der ausschlaggebenden Versagensmodi durch die einzelnen zerstörungsfreien Prüfverfahren und der Vergleich zu klassischen Messmethoden (z.B. Verformungsmessung mittels induktiver Wegaufnehmer). Die Biegeversuche wurden dazu durch Schallemissionsanalyse (SEA) und optische Verformungsanalyse mittels Bildkorrelation (DIC) begleitet. T2 - Fachtagung „Prüfen von Beton“ des InformationsZentrum Beton GmbH CY - Berlin, Germany DA - 06.10.2016 KW - Stahlbeton KW - Tragverhalten bei Biegebeanspruchung KW - Rissbildung KW - Schallemission KW - Optische Verformungsanalyse PY - 2016 AN - OPUS4-37820 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Manninger, Tanja A1 - Rübner, Katrin A1 - von Werder, Julia T1 - Eco friendly stabilization of loam with calcined clay and potassium hydroxide: a new approach to improve water resistance N2 - Earth buildings and adobe construction have been in use for thousands of years. Loam is locally available, environmentally friendly and has a small CO2 footprint mainly resulting from extraction and transport. Because of these reasons loam is one of the building materials of the future. Water resistance is an important aspect when using loam as a construction material. If the structural option of building protruding roofs cannot be implemented, the water resistance of clay can be improved by stabilization. Positive properties of the material should not be diminished by stabilization. For example, the desired regulation of air humidity, which however cannot be fully preserved by cement stabilization. For an alternative and more appropriate stabilisation, different mixtures with calcined clays with alkali activator were examined. The calcination temperature for clays is usually lower than for cement and starts at 600° C. The calcined clays therefore also have a lower CO2 footprint compared to cement. To keep the mixture environmentally friendly potassium was used as alkali ion. It could be proven that the alkali activated polymer enhances water resistance of the loam mixture. Provided some further optimization the material shows potential to replace cement without compromising on the positive properties of clay. T2 - International Conference on Regeneration and Conservation of Structures (ICRCS 2022) CY - Kyoto, Japan DA - 07.09.2022 KW - Loam KW - Alkali activation PY - 2022 SP - 1 EP - 4 AN - OPUS4-56396 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Herrmann, Ralf A1 - Schneider, Ronald A1 - Simon, Patrick A1 - Hille, Falk A1 - Said, Samir A1 - Baeßler, Matthias ED - Curbach, M. ED - Marx, S. ED - Scheerer, S. ED - Hampel, T. T1 - Structural Health Monitoring der Maintalbrücke Gemünden zur Unterstützung einer prädiktiven Instandhaltung N2 - Nach den bisherigen Regeln werden Bauwerksprüfungen von Brücken in starr definierten Intervallen durchgeführt. Diese starre, periodische, zustandsbasierte Instandhaltungsstrategie soll zukünftig durch eine flexible und prädiktive Instandhaltung ersetzt werden. Hierbei sollen Inspektionen und Instandhaltungsmaßnahmen unterstützt durch autonome Systeme auf der Grundlage von Monitoringdaten geplant und zusätzlich bei unvorhergesehenen Ereignissen ausgelöst werden. Im Rahmen des Verbundforschungsvorhabens AISTEC wird ein Vorgehen für Großbauwerke und kleinere Regelbauwerke zur Umsetzung eines kombinierten globalen, schwingungsbasierten und quasistatischen Monitorings entworfen. An der Maintalbrücke Gemünden – einer semiintegralen Rahmenbrücke aus Spannbeton auf der Schnellfahrstrecke Hannover–Würzburg – wurde als Demonstrator ein Dauermonitoring realisiert. T2 - 11. Symposium Experimentelle Untersuchungen von Baukonstruktionen (SEUB) CY - Online meeting DA - 08.03.2021 KW - Structural Health Monitoring KW - Umwelteinflüsse KW - Prädiktive Instandhaltung PY - 2021 UR - https://tu-dresden.de/bu/bauingenieurwesen/imb/ressourcen/dateien/veranstaltungen/seub/11-seub-2021/2021_SEUB11_06_Herrmann_et_al.pdf?lang=de VL - 55 SP - 66 EP - 76 PB - Technische Universität Dresden CY - Dresden AN - OPUS4-52810 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bartholmai, Matthias A1 - Strangfeld, Christoph T1 - RFID sensor systems embedded in concrete – systematical investigation of the transmission characteristics N2 - Long-term completely embedded sensor systems offer innovative possibilities for structural health Monitoring of concrete structures. Measuring of relevant parameters, e.g., temperature, humidity, or indication of corrosion can be performed with low energy sensors. This allows to implement passive RFID sensor systems without cable connection and battery, which are power supplied exclusively by the electromagnetic field from the external Reader device. To evaluate characteristics and conditions of this concept, a systematical Investigation of the transmission characteristics with variation of relevant parameters, as communication frequency, installation depth, type of concrete, moisture content, etc. is currently carried out in an interdisciplinary research project at BAM. First results are presented in this paper. T2 - 8th European Workshop On Structural Health Monitoring CY - Bilbao, Spain DA - 05.07.2016 KW - Embedded sensor KW - Energy harvesting KW - Wireless sensors KW - RFID sensors KW - Transmission characteristics KW - Structural health monitoring PY - 2016 AN - OPUS4-37130 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Diercks, Philipp A1 - Gläser, D. A1 - Unger, Jörg F. A1 - Crusoe, M. R. A1 - Huber, S. T1 - BAMresearch/NFDI4IngScientificWorkflowRequirements: Initial version N2 - Software-driven scientific workflows are often characterized by a complex interplay of various pieces of software executed in a particular order. The output of a computational step may serve as input to a subsequent computation, which requires them to be processed sequentially with a proper mapping of outputs to inputs. Other computations are independent of each other and can be executed in parallel. Thus, one of the main tasks of a workflow tool is a proper and efficient scheduling of the individual processing steps. Each processing step, just as the workflow itself, typically processes some input and produces output data. Apart from changing the input data to operate on, processing steps can usually be configured by a set of parameters to change their behavior. Moreover, the behavior of a processing step is determined by its source code and/or executable binaries/packages that are called within it. Beyond this, the computation environment not only has a significant influence on its behavior, but is also crucial in order for the processing step to work at all. The environment includes the versions of the interpreters or compilers, as well as all third-party libraries and packages that contribute to the computations carried out in a processing step. KW - Zenodo KW - 7790634 PY - 2023 DO - https://doi.org/10.5281/zenodo.7790633 PB - Zenodo CY - Geneva AN - OPUS4-59687 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hirsch, Philipp Daniel T1 - Innovative Ansätze der automatisierten Laserthermografie in industrienaher Anwendung N2 - In den vergangenen Jahren wurden vielfältige Möglichkeiten erforscht, wie sich aktive Thermografie in Fertigungs- und Instandhaltungsprozesse integrieren lässt. Eine Umsetzung mit Hilfe eines Industrieroboters und eines fasergekoppelten Diodenlasers als Wärmequelle, sowie gekühlter Wärmebildkamera und weiterer Sensorik bietet viele Freiheiten, reale Problemstellungen unter vielfältigen Bedingungen zu bearbeiten. Anhand von zwei anwendungsnahen Projekten werden verschiedene Lösungsansatze und die damit einhergehenden Herausforderungen vorgestellt. Der erste Anwendungsfall ist die automatisierte Rissprüfung durch Linienscans, welche eine präzise Rissdetektion und -lokalisierung ermöglicht, ohne wie bei klassischer Eindringprüfung auf den Einsatz von Farbstoffen und Entwicklern angewiesen zu sein. Darüber hinaus wird im zweiten Anwendungsfall die Erkennung von Lunkern in Gussbauteilen unter Zuhilfenahme zeitlicher Formung der thermischen Signale vorgestellt, was die Sensitivität und Verlässlichkeit gegenüber klassischer Pulsanregung deutlich erhöht. Ein wesentlicher Beitrag der vorgestellten Arbeit besteht in den verwendeten Ansätzen zur Robotersteuerung und der Korrektur von Oberflächeninhomogenitäten, die die Analyse thermografischer Daten bisher erschwerten. Diese Korrekturmethoden steigern die Genauigkeit der Prüfung, insbesondere bei variierenden Materialeigenschaften. Durch die Integration dieser Technologien in ein vollständig robotergestütztes System wird eine hohe Wiederholbarkeit und Effizienz erreicht, die besonders für industrielle Anwendungen von Vorteil sind. Die Ergebnisse zeigen, dass die Kombination von aktiver Laserthermografie, intelligenter Signalverarbeitung und Robotik eine vielseitige und hochgradig automatisierbare Lösung für die zerstörungsfreie Prüfung darstellt. Die vorgestellte Methode ermöglicht eine präzise Erkennung und Bewertung von Materialfehlern, wie Rissen und Lunkern, selbst unter anspruchsvollen Prüfbedingungen. Diese Fortschritte tragen zur Optimierung von Qualitätssicherungsprozessen bei und eröffnen neue Möglichkeiten für den Einsatz in unterschiedlichsten Industriezweigen. T2 - Jahrestagung der Deutschen Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) 2025 CY - Berlin, Germany DA - 26.05.2025 KW - Robotik KW - Laserthermografie KW - Emissionskorrektur KW - Multispektrale Bildverarbeitung KW - 3D-Bahnplanung KW - Automatisierte ZfP PY - 2025 AN - OPUS4-63250 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hirsch, Philipp Daniel T1 - Innovative Ansätze der automatisierten Laserthermografie in industrienaher Anwendung N2 - Die Kombination aus aktiver Thermografie und Robotik eröffnet neue Möglichkeiten für die automatisierte zerstörungsfreie Prüfung (ZfP) komplexer Bauteilgeometrien. In einem modular aufgebauten Prüfsystem kommen ein Faserlaser zur gezielten thermischen Anregung, ein Industrieroboter zur präzisen Positionierung sowie eine gekühlte IR-Kamera und weitere Sensorik zur Datenerfassung zum Einsatz. Im Zentrum der entwickelten Methode stehen vier wesentliche Komponenten: Erstens ermöglicht der Robotereinsatz eine hochpräzise und wiederholbare thermografische Inspektion entlang frei definierbarer Prüfpfade. Zweitens wird mithilfe einer Ulbricht-Kugel die ortsaufgelöste Emissionsgradkorrektur nicht-homogener Oberflächen durchgeführt – ein entscheidender Schritt für die quantitative Auswertung thermischer Signale. Drittens erhöht die Kombination von Infrarot- und VIS-Bilddaten die Sensitivität der Defekterkennung, insbesondere bei der Erkennung von Kanten und Strukturen. Viertens erlaubt die Integration eines 3D-Scanners die automatisierte Bahnplanung auf Basis von Punktwolken. Dadurch lassen sich komplexe Prüfteile flexibel erfassen, ohne aufwendige Vorrichtungen oder manuelle Vorpositionierung. Zusätzlich ermöglicht der Vergleich mit der Sollgeometrie eine Detektion geometrischer Abweichungen oder Verformungen. Das Gesamtsystem erlaubt eine vollständig automatisierte, anpassbare und hochsensitive Prüfung verschiedenster Bauteile. Die vorgestellte Kombination aus robotergestützter Thermografie, Emissionskorrektur, multispektraler Bildverarbeitung und intelligenter Bahnplanung stellt eine vielversprechende Lösung für ZfP-Anwendungen im industriellen Umfeld dar. Die Ergebnisse unterstreichen das Potenzial dieser Technologie als vielseitig einsetzbares, skalierbares Prüfverfahren. T2 - Jahrestagung der Deutschen Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) 2025 CY - Berlin, Germany DA - 26.05.2025 KW - Robotik KW - Laserthermografie KW - Emissionskorrektur KW - Multispektrale Bildverarbeitung KW - 3D-Bahnplanung KW - Automatisierte ZfP PY - 2025 UR - https://www.ndt.net/?id=31260 AN - OPUS4-63249 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lu, Xin T1 - Polarization diversity detection based wavelength scanning coherent optical time domain reflectometry N2 - Although wavelength scanning coherent optical time-domain reflectometry (WS-COTDR) system is immune to fading effect, it suffers from occasional and localized large errors caused by the false peak in the correlation spectrum due to the large signal generated in the random interference of the backscattered light. Polarization diversity detection is applied to a standard WS-COTDR system to suppress large measurement errors. In this way, the orthogonally polarized components of backscattered light can be obtained and processed separately. Due to the birefringence of the sensing fiber, the components experience different interference processes, so the average of their correlation spectrum can suppress the false peaks and finally reduce the occurrence of larger errors. The effectiveness of the proposed method is validated in laboratory for monitoring of sinusoidal vibrations and in field for tracking the bus movement via a dark fiber. T2 - 29th International Conference on Optical Fiber Sensors CY - Porto, Portugal DA - 26.05.2025 KW - Coherent optical time domain reflectometry KW - Traffic monitoring KW - Polarization diversity detection KW - Distributed fiber sensing PY - 2025 AN - OPUS4-63260 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Recknagel, Christoph A1 - Hoppe, Johannes A1 - Eilers, M. T1 - Technische Prüfvorschriften für die Dichtungsschicht aus einer Polymerbitumen-Schweißbahn zur Herstellung von Brückenbelägen auf Beton TL/TP-ING - Teil 7: Brückenbeläge, Abschnitt 1 N2 - Die "Technischen Prüfvorschriften für die Dichtungsschicht aus einer Polymerbitumen-Schweißbahn zur Herstellung von Brückenbelägen auf Beton" (TP BEL-B 1) enthalten alle notwendigen Angaben zur Durchführung der nach den "Technischen Lieferbedingungen für die Dichtungsschicht aus einer Polymerbitumen-Schweißbahn zur Herstellung von Brückenbelägen auf Beton" (TL BEL-B 1) geforderten Prüfungen. Art und Umfang der Einzelprüfungen sowie die entsprechenden Anforderungen sind den zugehörigen TL BEL-B 1 zu entnehmen. KW - Brückenbeläge KW - Asphaltbauweise KW - PmB Schweißbahn KW - Technische Anforderungen PY - 2022 SN - 978-3-86446-326-6 VL - 784/1 SP - 1 EP - 11 PB - FGSV Verlag GmbH CY - Köln AN - OPUS4-54857 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Renate A1 - Weise, Frank A1 - Pirskawetz, Stephan T1 - Numerische Simulation von Heat-Island-Phänomenen an innerstädtischen Straßenbelägen in Nagoya - Extreme Winterrandbedingungen T2 - Hannover-Messe 2007 (PST-Fraunhofer Patentstelle für die Deutsche Forschung) CY - Hanover, Germany DA - 16.04.2007 PY - 2007 AN - OPUS4-14673 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Renate A1 - Weise, Frank A1 - Pirskawetz, Stephan T1 - Numerische Simulation von Heat-Island-Phänomenen an innerstädtischen Straßenbelägen in Nagoya - Extreme Sommerrandbedingungen T2 - Hannover-Messe 2007 (PST-Fraunhofer Patentstelle für die Deutsche Forschung) CY - Hanover, Germany DA - 16.04.2007 PY - 2007 AN - OPUS4-14671 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weise, Frank T1 - Neuer Asphaltstraßenbelag für Japan zur Minderung von Heat-Island-Problemen T2 - Hannover-Messe 2007 CY - Hanover, Germany DA - 16.04.2007 PY - 2007 AN - OPUS4-14653 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weise, Frank T1 - Neuartige thermomechanische Systemprüfung von Asphaltstraßenbelägen T2 - Hannover-Messe 2007 (PST-Fraunhofer Patentstelle für die Deutsche Forschung) CY - Hanover, Germany DA - 16.04.2007 PY - 2007 AN - OPUS4-14654 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rai, Alena A1 - Stelzner, Ludwig A1 - Weise, Frank A1 - Wieland, M. T1 - 3D-Analyse von Betonfahrbahnoberflächen mit Grinding- und Groovingtextur mittels Streifenlichtprojektion N2 - Die Oberflächentexturierung der Betonfahrbahndecken mittels Grinding- und Grooving steht seit einigen Jahren im Mittelpunkt der Forschung und Entwicklung des Betonstraßenbaus in Deutschland. In den vergangenen Jahren wurden die vorteilhaften Oberflächenperformances derartiger Texturen wie z.B. Griffigkeit, Ebenheit, Lärmminderung in zahlreichen Forschungsprojekten umfassend untersucht und daraus die Technologie „Texturgrinding“ entwickelt. Im Kontext des gegenwärtig verfolgten ganzheitlichen performanceorientierten Ansatzes liegt der Fokus nun verstärkt auf der Analyse und Charakterisierung der Oberflächentopografie von Grinding- bzw. Groovingtexturen. Insbesondere gilt ein Hauptaugenmerk hierbei der zeitlichen Entwicklung der Oberflächentexturen in Abhängigkeit von äußeren Einwirkungen durch Klima und Verkehr. Dieser Beitrag zeigt, dass durch den Einsatz eines auf Streifenlichtprojektion basierenden Messsystems, eine hochaufgelöste dreidimensionale Erfassung der Oberflächentopografie verschiedenartiger Grinding- und Groovingtexturen möglich ist. Darauf aufbauend wurden messtechnische Voraussetzungen zur Gewährleistung reproduzierbarer Messungen geschaffen, die eine Dokumentation der zeitlichen Texturveränderungen infolge klimatischer Beanspruchung ermöglichen. Anschließend wurden Auswerteroutinen zur quantitativen und statistischen Charakterisierung der Oberflächentextur entwickelt und angewandt, um exemplarisch die Veränderungen der Oberflächentopografie infolge klimatischer Beanspruchung quantitativ abzubilden. KW - Betonfahrbahndecken KW - Grinding KW - Grooving KW - Oberflächentexturierung KW - Streifenlichtprojektion PY - 2020 DO - https://doi.org/10.1002/best.202000015 SP - 1 EP - 9 PB - Wilhelm Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG CY - Berlin AN - OPUS4-51012 LA - deu 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 - Bhuyan, M.D. A1 - Viefhues, Eva A1 - Döhler, M. A1 - Lecieux, Y. A1 - Mevel, L. A1 - Hille, Falk A1 - Schoefs, F. T1 - Output-only Subspace and Transfer Matrix-based Damage Localization and Quantification N2 - This paper deals with vibration-based damage localization and quantification from output-only measurements. We describe an approach which operates on a data-driven residual vector that is statistically evaluated using information from a finite element model, without updating the parameters of the model. First, the damaged elements are detected in statistical tests, and second, the damage is quantified only for the damaged elements. We propose a new residual vector in this context that is based on the transfer matrix difference between reference and damaged states, and compare it with a previously introduced subspace-based residual. We show localization and quantification on both residuals in simulations. T2 - 7th International Operational Modal Analysis Conference CY - Ingolstadt, Germany DA - 10.05.2017 KW - Hypothesis tests KW - Damage localization KW - Damage quantification PY - 2017 SN - 978-3-8440-5247-3 SN - 1610-4773 SP - 278 EP - 288 AN - OPUS4-40489 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wallau, Wilma 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 - 14th International Conference on Durability of Building Materials and Components CY - Gent, Belgium DA - 29.05.2017 KW - Building Materials KW - Alkali-silica reaction KW - Accelerated Concrete Prism Test KW - Continuous monitoring KW - Expansion modelling PY - 2017 AN - OPUS4-40495 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bartholmai, Matthias A1 - Strangfeld, Christoph A1 - Van Bocxlaer, A. T1 - RFID-Sensor-Transponder in Beton N2 - Sensor-Transponder-Lösung der BAM ermöglicht automatisiertes Brückenmonitoring und Predictive Maintenance und detektiert Korrosion in Beton. KW - RFID-Sensorsysteme KW - Bauteilintegrierte Sensoren KW - Betonkorrosion KW - Structural health monitoring PY - 2017 SN - 1860-5907 VL - 2017 IS - 5 SP - 46 EP - 49 PB - Verlag & Freie Medien, Lüneburg CY - Lüneburg AN - OPUS4-40873 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Oesch, Tyler T1 - In-situ analysis of water transport in concrete completed using X-ray computed tomography N2 - The water-transport characteristics of concrete have a major impact on its resistance to damaging chemical processes such as Alkali-Silica-Reaction (ASR). Water transport in samples of damaged and undamaged concrete was measured using in-situ CT. The resulting measurements of water-front movement relative to time and the change in 3D-moisture distribution within the samples, are needed for calibration and validation of water-transport numerical models. T2 - 3rd International Conference on Tomography of Materials and Structures CY - Lund, Sweden DA - 26.06.2017 KW - X-ray computed tomography (CT) KW - In situ KW - Water transport KW - Alkali-silica-reaction (ASR) PY - 2017 AN - OPUS4-40876 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kühne, Hans-Carsten T1 - Sicherheitskonzepte im Massivbau - Grundlagen bei der Bemessung und Ausführung von Stahlbeton- und Spannbetonbauwerken N2 - Der Anhang I der Bauproduktenverordnung EU 305/2011 definiert die an ein Bauwerk gestellten Grundanforderungen: „Bauwerke müssen als Ganzes und ihren Teilen für deren Verwendungszweck tauglich sein, wobei insbesondere der Gesundheit und der Sicherheit der während des gesamten Lebenszyklus der Bauwerke involvierten Personen Rechnung zu tragen ist“. Dementsprechend ist mit einer angemessenen Zuverlässigkeit ein mögliches Versagen des Bauwerkes auszuschließen und der vorgegebene Nutzungszweck ist für die vorgesehene Nutzungsdauer unter Berücksichtigung von wirtschaftlichen Gesichtspunkten zu gewährleisten. Anhand der vorliegenden Präsentation wird für den Bereich des Massivbaus ein Überblick über die maßgebenden Normen auf nationaler und europäischer Ebene gegeben. Dies beinhalt relevante Normen für die Bemessung von Bauwerken sowie die Anforderungen an die verwendeten Baustoffe und deren Überwachung. T2 - Informationveranstaltung der BAM CY - BAM, Berlin, Germany DA - 23.06.2017 KW - Sicherheitskonzept KW - Massivbau KW - Bemessung KW - Ausführung KW - Überwachung PY - 2017 AN - OPUS4-40908 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wolf, A. T. A1 - Recknagel, Christoph A1 - Wenzel, Norman A1 - Sitte, S. T1 - Structural Silicone Glazing: Life Expectancy of more than 50 Years? N2 - Structural Silicone Glazing (SSG) is a curtain walling method that utilizes silicone sealants to adhere glass, ceramic, metal or composite panels to supporting framing members by means of a peripheral adhesive joint. In SSG curtain walls, silicone sealants serve not only as a weather seal, but also act as a structural bonding element, eliminating the need for exterior retainers and covers. The paper discusses some essential findings of two recent research studies on the durability and service life of structural silicone glazing sealants and structures. The first study demonstrates, that specimens of a first generation 2-part silicone sealant taken from a SSG façade after 23+2 years of real life successfully passed the European ETAG002-1 performance criteria for residual strength. In a second study, a new performance-based durability test method was developed in partnership with the Federal Institute for Materials Research Berlin/Germany (BAM). This method is based on simultaneously exposing system test specimens to artificial weathering and complex, multiaxial mechanical loadings. 2-part structural silicone sealants of the first and of the second generation where subjected to this test, which is considered to correspond to an anticipated service life of 50 years. T2 - Glass Performance Days 2017 CY - Tampere, Finland DA - 28.06.2017 KW - Structural Sealant Glazing KW - Silicone adhesive KW - Durability KW - Climatic simulation KW - Artificial weathering KW - Mechanical loading PY - 2017 SN - 978-952-5836-06-6 SP - 338 EP - 345 PB - Glaston Finland Oy CY - Tampere, Finland AN - OPUS4-41288 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Larcher, M. A1 - Arrigoni, A. A1 - Bedon, C. A1 - van Doormaal, A. A1 - Haberacker, C. A1 - Hüsken, Götz A1 - Millon, O. A1 - Saarenheimo, A. A1 - Solomos, G. A1 - Thamie, L. A1 - Valsamos, G. A1 - Williams, A. A1 - Stolz, A. T1 - Recommendations for a new generation of standards for testing numerical assessment of blast-loaded glass windows N2 - The determination of the blast protection level of civil engineering buildings components against explosive effects represents a topic of crucial importance, in current practice. However, some key aspects of blast resistant structures design have been only marginally considered in the last decade, and currently still require appropriate regulations. This is especially true in the case of windows and facades, where the intrinsic material brittleness is the major influencing parameter for blast-resistant assemblies. While blast assessment of buildings and systems is usually achieved by means of experimental investigations, as well as numerical simulations, general regulations and guidelines are currently missing. In this regard, the European Reference Network for Critical Infrastructure Protection (ERNCIP) Thematic Group “Resistance of Structures to Explosion Effects” attempts to develop guidelines and recommendations aimed to harmonise test procedures in experimental testing of glass windows under blast, as well as standardized approaches for their vulnerability assessment via numerical modelling. In this paper, major Thematic Group outcomes and next challenges are briefly summarized. T2 - International Conference on Structural and Mechanical Engineering for Security and Prevention - ICSMESP 2017 CY - Prague, Czech Republic DA - 14.06.2017 KW - Blast protection KW - Blast loaded glass windows KW - Experimental testing KW - Finite element numerical modelling KW - Standardisation PY - 2017 DO - https://doi.org/10.4028/www.scientific.net/KEM.755.121 SN - 1662-9795 VL - 755 SP - 121 EP - 130 PB - Trans Tech Publications Inc. CY - Zurich, Switzerland AN - OPUS4-41927 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ebell, Gino T1 - Galvanic Anode systems in Concrete structures and their performance part 1 N2 - Corrosion of reinforcement is one of the major reasons in questioning the sturdiness of building structures. The application of cathodic protection techniques plays a big role in controlling the corrosion process to ensure a longer service life of building structures. This systematic study compares the efficiency and durability of various discrete galvanic zinc anode systems available in the current market using different criteria for measuring efficiencies such as potential measurements, electrolyte resistance measurements and several polarization methods to determine the polarizability of the anodes. Results to validate the performance of long-time exposure of discrete zinc anodes in the concrete medium are already shown in 2021. Now the results of analyzing the phase boundary between mortar and anodes by using 3D computer tomography are shown, as also the field application at large-scale specimens where the potential distribution and the current were investigated. T2 - Eurocorr 2023 CY - Brussels, Belgium DA - 27.08.2023 KW - Corrosion KW - Corrosion Protection PY - 2023 AN - OPUS4-58169 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ebell, Gino T1 - Potential Mapping at Concrete Structures N2 - Electrochemical potential mapping is a recognized technique for the localization of corroding reinforcing steels. Areas of corroding reinforcement steel can be located in a non-destructive manner by means of this procedure. Half‐cell potential measurements are used in order to detect chloride‐induced corrosion. However, it is not recommended in order to assess the risk of carbonation‐induced corrosion. For this purpose, determining the carbonation depth and the concrete cover appears more appropriate. The content of this specification exclusively refers to the application of mobile, local variable reference electrodes, which are only placed on the concrete surface while measuring. The technique distinguishes itself thereby from the range of corrosion monitoring systems with stationary installed reference electrodes and sensor systems, respectively, whereby it is possible to continuously track measurements within the area of the installed electrodes. However, these methods are not dealt with in this specification. T2 - NDT&E Workshop 2024 CY - Baruth/Mark, Germany DA - 03.07.2024 KW - Corrosion KW - Potential mapping PY - 2024 AN - OPUS4-60584 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - INPR A1 - Boschmann Käthler, C. A1 - Ebell, Gino A1 - Keßler, S. A1 - Schiegg, Y. A1 - Dauberschmidt, C. A1 - Angst, U. M. T1 - A comparison of methods to assess the resistance of reinforcing steel against chloride‐induced corrosion in concrete: Particular consideration of 12% chromium steel N2 - The critical chloride content C(crit) is an indicator for the corrosion resistance of reinforcing steels in concrete. In this article, several experimental methods for determining the critical chloride content C(crit) of mild and an alloyed (12% Cr) steel in cementitious materials are compared. The methods used include accelerated polarization tests and tests using more natural (unpolarized) conditions in which chloride ingress occurs by diffusion and capillary uptake. The advantages and disadvantages of the methods are discussed, in particular, with the objective of reaching a compromise between applicability to practice and feasibility in laboratory testing. KW - Chloride‐induced corrosion KW - Critical chloride content KW - Reinforced concrete KW - Testing methods PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529751 DO - https://doi.org/10.1002/maco.202112609 SN - 1521-4176 SP - 1 EP - 20 PB - Wiley-VCH CY - Weinheim AN - OPUS4-52975 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Seyhan, E. A1 - Ebell, Gino A1 - Jimenez, D. A1 - Chavez, J. A1 - Sanchez Alvarez, G T1 - Evaluation of SACI performance on reinforced concrete structures N2 - Surface applied corrosion inhibitors (SACI) are widely used to mitigate corrosion process of steel reinforcement in concrete. But they remain controversial as to their effectiveness and the ability to compare materials from different manufacturers and technologies. They are applied onto the surface of hardened concrete and penetrate towards steel reinforcement. This paper discusses the corrosion inhibition performances of dual-phase surface applied corrosion inhibitor and the efficiency of the corrosion inhibitor is assessed by selected testing procedures in BAM laboratories. T2 - ACHE 2022 CY - Santander, Spain DA - 20.06.2022 KW - Corrosion KW - Inhibitor PY - 2022 AN - OPUS4-55095 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schalau, Sebastian A1 - Habib, Abdel Karim T1 - Atmospheric wind field modelling with OpenFOAM for near-ground gas dispersion N2 - CFD simulations of near-ground gas dispersion depend significantly on the accuracy of the wind field. When simulating wind fields with conventional RANS turbulence models, the velocity and turbulence profiles specified as inlet boundary conditions change rapidly in the approach flow region. As a result, when hazardous materials are released, the extent of hazardous areas is calculated based on an approach flow that differs significantly from the boundary conditions defined. To solve this problem, a turbulence model with consistent boundary conditions was developed to ensure a horizontally homogeneous approach flow. Instead of the logarithmic vertical velocity profile, a power law is used to overcome the problem that with the logarithmic profile, negative velocities would be calculated for heights within the roughness length. With this, the problem that the distance of the wall-adjacent cell midpoint has to be higher than the roughness length is solved, so that a high grid resolution can be ensured even in the near-ground region which is required to simulate gas dispersion. The evaluation of the developed CFD model using the German guideline VDI 3783/9 and wind tunnel experiments with realistic obstacle configurations showed a good agreement between the calculated and the measured values and the ability to achieve a horizontally homogenous approach flow. KW - OpenFOAM KW - Gas dispersion KW - Atmospheric boundary layer KW - Turbulence model PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539095 DO - https://doi.org/10.3390/atmos12080933 VL - 12 IS - 8 SP - 933 PB - MDPI AN - OPUS4-53909 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Salari, Farid A1 - Zocca, Andrea A1 - Bosetti, Paolo A1 - Hlaváček, Petr A1 - Italiano, Antonino A1 - Gobbin, Filippo A1 - Colombo, Paolo A1 - Kühne, Hans-Carsten A1 - Sglavo, Vincenzo M. T1 - Powder-bed 3D printing by selective activation of magnesium phosphate cement: Determining significant processing parameters and their effect on mechanical strength N2 - The present work addresses powder bed binder jetting additive manufacturing by selective magnesium phosphate cement activation. Despite the potential of this technology to aid the digitalization of the construction industry, the effect of processing parameters on the mechanical performance of printed materials has not yet been studied to generate a guideline for the further development of the technology. Statistical methodologies were used to screen the effect of four printing process parameters (printing speed, layer thickness, raster angle, and build direction on flexural and compressive strength). As the exploited technology works with constant fluid pressure, the physical interpretation of the effect of each factor can be considered taking into account the interactions between the binder materials in the powder bed. Analysis of variance (ANOVA) indicated that printing speed and layer thickness significantly affect mechanical performances. Furthermore, the layout of samples for the printing process is preferable to be parallel the printhead movement. An anisotropic behavior was observed, and the samples subjected to compressive forces parallel to the layer plane possessed lower strength values. This effect can be interpreted as a result of a weak area of low density in between layers, leading to a pronounced delamination under compression. Even though the strength of the printed material is not suitable for a structural concrete, it can be marginally improved by design of experiment and optimized for non-structural applications, such as for porous artificial stone. Design of experiment coupled with ANOVA methods can be used in the future to support the development of novel material mixtures, thus expanding the fields of application of this novel additive manufacturing technology. KW - Concrete 3D-printing KW - Particle-bed binder jetting KW - Design of experiment PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601654 DO - https://doi.org/10.1016/j.oceram.2024.100609 VL - 18 SP - 1 EP - 11 PB - Elsevier B.V. AN - OPUS4-60165 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Villani, P. A1 - Unger, Jörg F. A1 - Weiser, M. T1 - Adaptive Gaussian process regression for Bayesian inverse problems N2 - We introduce a novel adaptive Gaussian Process Regression (GPR) methodology for efficient construction of surrogate models for Bayesian inverse problems with expensive forward model evaluations. An adaptive design strategy focuses on optimizing both the positioning and simulation accuracy of training data in order to reduce the computational cost of simulating training data without compromising the fidelity of the posterior distributions of parameters. The method interleaves a goal-oriented active learning algorithm selecting evaluation points and tolerances based on the expected impact on the Kullback-Leibler divergence of surrogated and true posterior with a Markov Chain Monte Carlo sampling of the posterior. The performance benefit of the adaptive approach is demonstrated for two simple test problems. T2 - Algoritmy 2024 - Central-European Conference on Scientific Computing CY - Vysoké Tatry, Slovakia DA - 15.03.2024 KW - Gaussian process regression KW - Bayesian inverse problems KW - Surrogate models KW - Parameter identification KW - Active learning PY - 2024 SP - 1 EP - 10 PB - Slovak University of Technology CY - Bratislava AN - OPUS4-60738 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Strangfeld, Christoph T1 - Moisture testing and mapping N2 - Most building materials are porous and hydrophilic. Thus, for condition assessment and damage detection a determination of the material moisture is required. In this lecture, a short overview is given regarding moisture transport in porous media in the hygroscopic range. Then, several non-destructive measurement techniques are introduced. Here, the focus lies on their practical application and limitations. T2 - NDT&E Advanced Training Workshop CY - Berlin, Germany DA - 03.07.2024 KW - Building materials KW - Concrete KW - Material moisture KW - Moisture measurement techniques KW - Moisture transport PY - 2024 AN - OPUS4-60605 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hothan, Sascha T1 - Forschungsprojekt "INSIST" N2 - Der Vortrag zeigt den Bearbeitungsstand des Forschungsvorhabens "Entwicklung eines Verfahrens zur in situ Bewertung des Feuerwiderstands von bestehenden Stahlkonstruktionen mit reaktiven Brandschutzsystem (RBS)" (INSIST). Die Entwicklung und der Bau eines Geräteprototyps wurden vorgenommen und ein Konzept zur Kalibration erarbeitet. Die bisherigen Untersuchungen belegen, dass das Verfahren Ergebnisse liefert, die denen konventioneller Brandversuche im untersuchten Parameterbereich gleichwertig sind. T2 - Sachverständigenausschuss Reaktive Baustoffe und Beschichtungen -B- (463a) des Deutschen Institutes für Bautechnik CY - Berlin, Germany DA - 13.02.2024 KW - INSIST KW - In situ Bewertung KW - RBS PY - 2024 AN - OPUS4-60777 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Birgit 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 - Ibausil 2023 CY - Weimar, Germany DA - 13.09.2023 KW - Beton KW - Digitalisierung KW - Datenmanagement KW - FAIR-Prinzip KW - Metadaten KW - Ontologie KW - Wissensgraph PY - 2023 AN - OPUS4-60964 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Strangfeld, Christoph T1 - Moisture diffusion affected by the Knudsen effect in temporal changing pore networks N2 - Almost all building materials in civil engineering have an open porosity and interact with or are affected by the environmental conditions. Structures might suffer from effects such as moisture adsorption, carbonation, corrosion, penetration of salt ions and chemical substances, etc. In the hygroscopic range, these processes are mostly driven by diffusion. Due to the confinement of small pores ( 1 m), the Knudsen effect reduces the molecular diffusion. This reduction can become more significant in case of temporal changing pore systems because of physisorption of water vapor, carbonation, or chemisorption. In this study, unstabilised earth blocks and earth masonry are investigated. In a first step, the pore size distribution of the blocks is measured and sorption isotherms are recorded in experiments. Besides the ordinary physisorption, the involved clay minerals undergo swelling or shrinking due to chemisorption. The following two effects must be considered: first, the reduction of the available pore space by the adsorbed water layer. For this, the Hillerborg sorption theory is used, which is a combination of the well-known Brunauer-Emmett-Teller sorption theory and the Kelvin equation. This allows the computation of adsorbed water layers even in curved pore geometries. Second, the variation of the initial pore size distribution due to chemisorption needs to be modelled. Based on these two models, the effective diffusion coefficient can be predicted. For validation, arrays of relative humidity sensors were embedded into a free-standing earth masonry wall. This monitoring was carried out over more than a year to have a broad variety of environmental conditions and was located in Berlin, Germany. The prediction of the effective diffusion coefficient can also be transferred to other processes and allows the investigation of materials having temporarily changing pore systems. Examples are the carbonation of cementitious materials, alkali silica reaction, calcium leaching of long-lasting structures, etc. This effect becomes most prominent in the meso-pore range and might alter the effective diffusion coefficient by more than 100 %. T2 - 4th International Congress on Materials & Structural Stability CY - Rabat, Morocco DA - 08.03.2023 KW - Earth masonry KW - Material moisture KW - Molecular diffusion KW - Chemisoprtion KW - Knudsen effect KW - Physisorption PY - 2023 AN - OPUS4-57140 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sperlich, Tim A1 - Häßler, Dustin A1 - Stelzner, Ludwig A1 - Hothan, Sascha T1 - In situ Prüfmethode zur Untersuchung des Feuerwiderstands von bestehenden Stahlkonstruktionen mit reaktivem Brandschutzsystem N2 - Der Beitrag beschreibt die Entwicklung eines neuartigen in situ Nachweisverfahrens zur Beurteilung des Feuerwiderstandes von bestehenden Stahlkonstruktionen mit gealtertem reaktivem Brandschutzsystem (RBS). Derzeit ist ein solcher Nachweis ausschließlich anhand eines Bauteilbrandversuchs möglich. Hierzu muss ein Bauteil aus der Bestandskonstruktion entnommen und einer zerstörenden Brandprüfung unterzogen werden. In Zusammenhang mit der Dauerhaftigkeitsbewertung von RBS für Zeiträume von mehr als 10 Jahren besteht in der Praxis vermehrt der Bedarf an einem minimal invasiven Prüfverfahren, mit dessen Hilfe sich direkt am Bestandsbauwerk die tatsächlich vorhandene Leistungsfähigkeit des gealterten RBS überprüfen lässt. Durch einen erfolgreichen Funktionsnachweis wäre eine Weiternutzung der Bestandkonstruktion bei Aufrechterhaltung des bestehenden Sicherheitsniveaus möglich. T2 - Symposium Heißbemessung - Structural Fire Engineering CY - Braunschweig, Germany DA - 05.09.2023 KW - Brandschutz KW - Stahlbau KW - reaktives Brandschutzsystem KW - Prüfmethode KW - Brandversuch PY - 2023 SP - 1 EP - 16 PB - TU Braunschweig CY - Braunschweig AN - OPUS4-58180 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sperlich, Tim T1 - In situ Prüfmethode zur Untersuchung des Feuerwiderstands von bestehenden Stahlkonstruktionen mit reaktivem Brandschutzsystem N2 - Der Beitrag beschreibt die Entwicklung eines neuartigen in situ Nachweisverfahrens zur Beurteilung des Feuerwiderstandes von bestehenden Stahlkonstruktionen mit gealtertem reaktivem Brandschutzsystem (RBS). Derzeit ist ein solcher Nachweis ausschließlich anhand eines Bauteilbrandversuchs möglich. Hierzu muss ein Bauteil aus der Bestandskonstruktion entnommen und einer zerstörenden Brandprüfung unterzogen werden. In Zusammenhang mit der Dauerhaftigkeitsbewertung von RBS für Zeiträume von mehr als 10 Jahren besteht in der Praxis vermehrt der Bedarf an einem minimal invasiven Prüfverfahren, mit dessen Hilfe sich direkt am Bestandsbauwerk die tatsächlich vorhandene Leistungsfähigkeit des gealterten RBS überprüfen lässt. Durch einen erfolgreichen Funktionsnachweis wäre eine Weiternutzung der Bestandkonstruktion bei Aufrechterhaltung des bestehenden Sicherheitsniveaus möglich. T2 - Symposium Heißbemessung - Structural Fire Engineering CY - Braunschweig, Germany DA - 05.09.2023 KW - Brandschutz KW - Stahlbau KW - Reaktives Brandschutzsystem KW - Prüfmethode KW - Brandversuch PY - 2023 AN - OPUS4-58183 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rosenbusch, Sjard Mathis T1 - Mesh-convergence and gradient-enhanced models in blast simulations of concrete structures N2 - Blast experiments on reinforced concrete structures are often limited to small structures and therefore simple shock waves. Such experiments are carried out at the Bundesanstalt für Materialforschung und -prüfung (BAM) and the structural response is investigated using several measuring methods. Complex load scenarios that occur as a result of reflection of the shock wave in larger structures are harder to realise in practice. Numerical simulations for the propagation of the shock wave and the structural response can therefore be an alternative method for the investigation of blast loads on complex structures. For the simulation of concrete under impact and blast loads, several local constitutive models exist that are formulated as plasticity models with softening taken into account by introducing a scalar damage field. Local damage models however often lead to mesh-dependent results which do not converge with mesh refinement. In order to achieve meaningful predictions from numerical experiments, independence from the mesh is needed. In this contribution, the JH2 model (Johnson and Holmquist 1994) with a parameter set for concrete is investigated in a simple blast load scenario. The shockwave is implemented as a simplified Friedlander-curve and the overpressures are applied as a boundary condition for the structural simulation. In order to account for large displacements that can occur during blast loads, an updated Lagrangian formulation is utilised. A Runge-Kutta method with adaptive time stepping is used to advance the solution in time. The open source FEM software FEniCS (Logg et al. 2012) is used together with an implementation of the JH2 model which has been developed at BAM. An extensive convergence analysis with both timestep- and mesh-refinement is carried out to show the mesh dependency. In order to make the results independent of the mesh, possible nonlocal versions of the JH2 model with gradient-enhancement are presented. Since many damage models for concrete share the damage mechanism of the JH2 model, the application of the regularisation methods to more complex material models, like the RHT model (Grunwald et al. 2017), is also discussed. Advantages of a gradient-enhanced formulation to simulate dynamic strength increase of concrete, as suggested in (Häußler-Combe and Kitzig 2009), is discussed as well. T2 - ECCOMAS YIC 2023 CY - Porto, Portugal DA - 19.06.2023 KW - Gradient-Damage KW - Explicit Dynamics KW - Concrete Modeling KW - Mesh Convergence PY - 2023 AN - OPUS4-58717 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Neumann, Patrick P. A1 - Bartholmai, Matthias T1 - Towards Autonomous NDT Inspection: Setup and Validation of an Indoor Localization System N2 - Monitoring and maintenance of civil infrastructure are of great importance, as any undetected damage can cause high repair costs, unintended deadtime, or endanger structural integrity. The inspection of large concrete structures such as bridges and parking lots is particularly challenging and time-consuming. Traditional methods are mostly manual and involve mapping a grid of measurement lines to record the position of each measurement. Current semi-automated methods, on the other hand, use GPS or tachymeters for localization but still require trained personnel to operate. An entirely automated approach using mobile robots would be more cost- and time-efficient. While there have been developments in using GPS-enabled mobile robots for bridge inspection, the weak signal strength in indoor areas poses a challenge for the automated inspection of structures such as parking lots. This paper aims to develop a solution for the automated inspection of large indoor concrete structures by addressing the problem of robot localization in indoor spaces and the automated measurement of concrete cover and rebar detection. T2 - 39th Danubia-Adria Symposium on Advances in Experimental Mechanics CY - Siófok, Hungary DA - 26.09.2023 KW - NDT Inspection KW - Mobile Robot KW - Indoor Localization KW - Setup and Validation PY - 2023 AN - OPUS4-58662 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -