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 T2 - 10. Kolloquium Industrieböden Fachtagung über stark beanspruchte Bodenkonstruktionen Tagungshandbuch 2020 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 - Gardei, André A1 - Meng, Birgit ED - Caprai, V. ED - Brouwers, H. J. H. T1 - Functionalization of fibres for cement-based materials - selected test methods T2 - Proceedings ICSBM 2019 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 - 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 T2 - HighTechMatBau Neue Materialien im Bauwesen - Tagungsband mit Beiträgen zur Konferenz vom 31. Januar 2018 in Berlin 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 - CONF A1 - Gardei, André A1 - Drabetzki, Philipp T1 - Probenpräparation für LIBS-Messungen - ein häufig unterschätztes Thema N2 - Die Probenpräparation ist ein Teil im Prozess der Baustoffuntersuchung und muss dementsprechend sorgfältig geplant werden. Die Probenpräparation ist letztendlich der Grundstein für alle folgenden Untersuchungen, somit wirken sich alle hier getroffenen Entscheidungen direkt auf die Qualität der Ergebnisse aus. T2 - Fachtagung Bauwerksdiagnose CY - Berlin, Germany DA - 15.02.2018 KW - Probenpräparation KW - LIBS PY - 2018 AN - OPUS4-44656 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Miccoli, Lorenzo A1 - Gerrard, C. A1 - Perrone, C. A1 - Gardei, André A1 - Ziegert, C. T1 - A collaborative engineering and archaeology project to investigate decay in historic rammed earth structures: The case of the Medieval preceptory in Ambel JF - International Journal of Architectural Heritage N2 - This study assesses the structural vulnerability of part of a later medieval earthen building at Ambel (near Zaragoza, Spain), once a preceptory or monastic house belonging to the Military Orders. An inspection of its morphology and materials coupled with the results of an extensive campaign of static monitoring reveals marked structural inhomogeneities, the product of more than a thousand years of construction, failure, and repair from the 10th century to the present day. Building materials are inappropriately juxtaposed, there are discontinuities between construction phases and fundamental concerns remain over the long-term stability of the structure. The current condition of the structure is mainly influenced by structural discontinuities introduced at the time of construction, the unintended consequences of repair and modification and the material decay that has affected the base of the rammed earth walls. The overall findings of the static monitoring show that there is no related damage, variations in crack widths are related to the building seasonal cycle. While static analysis is an essential prerequisite before a suitable maintenance program can be fully defined, this study argues that no evaluation of the structural behavior of any historic building can afford to ignore its archaeological “biography” of modification and repair. KW - Archaeology KW - Historical earthen building KW - Materials characterization KW - Rammed earth KW - Static monitoring PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-396274 DO - https://doi.org/10.1080/15583058.2016.1277283 VL - 11 IS - 5 SP - 636 EP - 655 PB - Taylor & Francis Group AN - OPUS4-39627 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Miccoli, Lorenzo A1 - Fontana, Patrick A1 - Gardei, André A1 - Ziegert, C. A1 - Perrone, Ch. A1 - Kaiser, C. A1 - Gerrard, Ch. ED - Feiglstorfer, H. T1 - Analysis and diagnosis of earthen buildings: the case of Ambel preceptory in Aragon, Spain T2 - earth construction & tradition N2 - This study presents diagnostic techniques to assess the structural vulnerability of earthen buildings. Medieval structures at Ambel (near Zaragoza, Spain), once a preceptory or monastic house belonging to the Military Orders, provide a useful case study. After more than a thousand years of construction, failure and repair from the 10th century to the present day, Ambel preceptory today is characterised by marked inhomogeneities: construction materials and structural typologies are juxtaposed, with structural discontinuities at the interfaces between construction phases. This paper argues that, while static analysis is an essential prerequisite before a suitable maintenance program can be defined, no evaluation of the structural behaviour of any historic building can ignore an understanding of the building’s history. KW - historical earthen building KW - rammed earth KW - material characterisation KW - static monitoring PY - 2016 SN - 978-3-900265-34-2 VL - 1 SP - 201 EP - 229 PB - IVA-Verlag CY - Vienna, Austria AN - OPUS4-37076 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 T2 - 15th Euroseminar on microscopy applied to building materials 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 - Kargol, Marta A1 - Müller, Urs A1 - Gardei, André T1 - Properties and performance of silane: blended cement systems JF - Materials and structures N2 - The paper presents the results of a study dealing with the performance of water repellents on hardened blended cement pastes. Since on the European market Portland cement does not play the dominant role anymore and due to the new national and European policies concerning Greenhouse Gases and sustainability, cement manufacturers produce more and more blended cements (CEM II–CEM V). Nevertheless, the majority of experience concerning the efficacy of water repellents is gained from Portland cement; therefore knowledge in regard to the interactions of blended cement with water repellent agent is minimal. Two silane-based products were applied on 'fresh' and carbonated cement substrates containing limestone, fly ash, slag and trass, and were investigated in terms of their functionality. The evaluation of the treatments' performance and effectiveness were assessed using various laboratory measurements. Hydrophobicity, water absorption, colour changes and the penetration depth of silanes into the substrate were evaluated before and after artificial aging experiments. Moreover, the outdoor weathering test was performed to shed light on treated surface appearance in a 'real' outdoor environment. The results showed that surface wettability was independent on water ingress or colour variations, especially for cement specimens artificially aged by accelerated carbonation. Cement pastes containing slag and trass seemed to more distinctly affect the water repellents' surface performance. KW - Water repellents KW - Silanes KW - Impregnation KW - Aging KW - Carbonation KW - Durability KW - Blended cement KW - Fly ash KW - Hydrophobicity KW - Hydrophobic agent PY - 2013 DO - https://doi.org/10.1617/s11527-012-9984-1 SN - 1359-5997 SN - 1871-6873 VL - 46 IS - 9 SP - 1429 EP - 1439 PB - Springer CY - Dordrecht AN - OPUS4-31839 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Miccoli, Lorenzo A1 - Perrone, C. A1 - Müller, Urs A1 - Gardei, André A1 - Ziegert, C. ED - Drochytka, R. ED - Bohus, S. T1 - Structural performances of earthen building materials. A comparison between different typologies T2 - 2nd WTA - Internaitonal PhD Symposium - Building materials and buidling technology to preserve the built heritage N2 - Traditional construction techniques utilizing earthen materials are often seen as inferior compared to modern ways of building. Structural earthen elements are perceived as vulnerable towards environmental influences (moisture, frost) and in particular towards the load scenarios during earthquakes. In comparison to the recent advances in research on stone and brick masonry, knowledge on the structural performance of earthen building construction is limited and scattered. Consequently the confidence in the performance of these earthen buildings constructed in the traditional techniques during earthquakes is fairly low. The research presented here aims to make a comparison of mechanical behavior between different earth masonry material typologies, consisting of earth block masonry, rammed earth and cob. The paper has been developed in the framework of a larger research program called NIKER. BAM and other seventeen research partners from the Mediterrean area are jointly involved to develop and validate innovative materials and technologies for the systemic improvement of the seismic behavior of Cultural Heritage assets T2 - 2nd WTA - Internaitonal PhD Symposium - Building materials and buidling technology to preserve the built heritage CY - Brno, Czech Republic DA - 06.10.2011 KW - Earth masonry KW - Material test KW - Mechanical behavior KW - Cultural heritage PY - 2011 SN - 978-3-937066-21-9 SN - 0947-6830 N1 - Serientitel: WTA-Schriftenreihe – Series title: WTA-Schriftenreihe VL - 2 / Part 2 IS - 36 SP - 86 EP - 94 PB - WTA Publications AN - OPUS4-24928 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -