TY - JOUR A1 - Heap, M.J. A1 - Lavallée, Y. A1 - Laumann, A. A1 - Hess, K.-U. A1 - Meredith, P.G. A1 - Dingwell, D.B. A1 - Huismann, Sven A1 - Weise, Frank T1 - The influence of thermal-stressing (up to 1000 °C) on the physical, mechanical, and chemical properties of siliceous-aggregate, high-strength concrete JF - Construction and building materials N2 - High-strength concrete (HSC) will experience thermal microcracking, explosive spalling, and undesirable chemical changes when exposed to high temperatures, such as during fire, engulfment by lava flow, or nuclear meltdown. Knowledge of the resultant changes in mechanical, physical, and chemical properties is paramount for hazard mitigation. We present a multidisciplinary study on the influence of thermal-stressing on HSC. Our study shows that thermal microcracking in HSC initiates at 180 °C, is more prevalent during cooling, and exhibits the Kaiser 'temperature-memory' effect. We show that residual compressive strength, indirect tensile strength, ultrasonic wave velocities, and Young’s modulus and Poisson’s ratio decrease, whilst porosity and permeability increase with increasing temperature. We discuss these data in terms of the chemical changes during thermal-stressing, provided by thermo-gravimetric analysis, differential scanning calorimetry, and X-ray diffraction, and from optical microscopic analysis of thermally-stressed samples. We provide implications for thermally-damaged HSC structures and a new method for non-destructive monitoring. KW - High strength concrete KW - Fire KW - Thermal-stressing KW - Acoustic emissions KW - Physical properties KW - Elastic moduli KW - Uniaxial compressive strength KW - Indirect tensile strength KW - Thermo-gravimetric analysis KW - X-ray diffraction PY - 2013 DO - https://doi.org/10.1016/j.conbuildmat.2013.01.020 SN - 0950-0618 VL - 42 SP - 248 EP - 265 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-27992 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pirskawetz, Stephan A1 - Weise, Frank A1 - Fontana, Patrick ED - van Breugel, K. ED - Ye, G. ED - Sun, W. ED - Miao, C. T1 - Analysis of early-age cracking of cementitious materials by combination of various non destructive testing methods T2 - 2nd International conference on microstructural-related durability of cementitious composites (RILEM proceedings / PRO 83) T2 - 2nd International conference on microstructural-related durability of cementitious composites CY - Amsterdam, The Netherlands DA - 2012-04-11 KW - Self-desiccation shrinkage KW - Nondestructive testing KW - Acoustic emission KW - Microcracking PY - 2012 SN - 978-2-35158-129-2 IS - 83 SP - 1 EP - 10 AN - OPUS4-25769 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Huismann, Sven A1 - Weise, Frank A1 - Meng, Birgit A1 - Schneider, U. T1 - Transient strain of high strength concrete at elevated temperatures and the impact of polypropylene fibers JF - Materials and structures N2 - This paper presents the results of an experimental study on the transient strain of high strength concrete (HSC) under heating up to 750 °C and the impact of polypropylene (PP) fibers. Concerning this topic only few results are available in the literature and systematic investigations are missing. However, basic knowledge is necessary for the understanding of the internal damage processes in the material as well as for heated structures. The transient strain during heating can be separated in two basic components: the free thermal strain and the mechanical strain. They were experimentally determined exemplarily for one HSC. For the determination of the mechanisms of transient strain and particularly the influence of PP fibers different techniques were applied. In this context the monitoring of the microcracking was done for the first time with acoustic emission analysis in combination with ultrasonic measurements. This new approach helps fundamentally to explain the impact of PP fibers on free thermal strain and mechanical strain during heating up. Furthermore weight loss measurements were carried out to characterize the moisture transport. It was shown that the PP fibers cause an acceleration of the moisture transport in the temperature range from 200 to 250 °C which leads to drying shrinkage in opposite direction to the free thermal strain. Hence this paper is a contribution to the general understanding of the impact of PP fibers in HSC at high temperatures and emphasizes the important influence of PP fibers on the thermal and mechanical induced strain of HSC. KW - High strength concrete KW - Polypropylene fibers KW - Elevated temperatures KW - Transient strain KW - Acoustic emission KW - Ultrasound PY - 2012 DO - https://doi.org/10.1617/s11527-011-9798-6 SN - 1359-5997 SN - 1871-6873 VL - 45 IS - 5 SP - 793 EP - 801 PB - Springer CY - Dordrecht AN - OPUS4-26029 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pistol, Klaus A1 - Weise, Frank A1 - Meng, Birgit T1 - Polypropylen-Fasern in Hochleistungsbetonen - Wirkungsmechanismen im Brandfall JF - Beton- und Stahlbetonbau N2 - Bauteile bzw. Tragwerke aus Hochleistungsbetonen müssen in der Regel gegen brandinduzierte Abplatzungen mit geeigneten Maßnahmen geschützt werden, um einen ausreichenden Feuerwiderstand im Brandfall zu gewährleisten. Die bisher wirtschaftlich und technologisch sinnvollste Methode zur Verhinderung von explosionsartigen Betonabplatzungen im Brandfall ist die Zugabe von Polypropylen-Fasern. Die Wirksamkeit der Fasern konnte zwar empirisch gezeigt werden, es stellt sich allerdings die Frage, welche Mechanismen zur Verhinderung der Abplatzungen führen. Der vorliegende Beitrag fasst bisherige Theorien zur Wirkungsweise von Polypropylen-Fasern in brandbeanspruchten Hochleistungsbetonen zusammen und stellt eine innovative Methodologie zur Erforschung der mikrostrukturellen Prozesse vor. Die Ergebnisse zeigen, dass die nach dem Schmelzen und Zersetzen der Polypropylen-Fasern frei werdenden Mikrokanäle durch eine gleichzeitig einsetzende Mikrorissbildung netzartig verbunden werden. Die Mikrorissbildung ermöglicht somit den Abbau von Eigen- und Zwangsspannungen im Beton (mechanischer Effekt) und die Entstehung eines Transportwegesystems für den ausströmenden Wasserdampf (Permeationseffekt).--------------------------------------------------------------------------- Structural members and bearing structures of high performance concrete generally have to be protected against explosive spalling due to fire exposure to guarantee a sufficient fire resistance. Up to now, the economically and technologically most worthwhile method to prevent explosive spalling is the addition of polypropylene fibres. Though the effectiveness of the fibres could be shown empirically, the mechanisms preventing explosive spalling are still debatable. The present article summarizes the existing theories concerning the mode of action of polypropylene fibres in fire exposed high performance concretes and presents an innovative methodology for analysing the micro structural processes. The results show that due to the thermal decomposition of the polypropylene fibres micro channels are created and simultaneously connected due to a netlike micro crack formation. This enables the relief of internal stresses (mechanical effect) and the formation of a permeable transport system for the escaping water vapour (permeation effect). KW - Polypropylen-Fasern KW - Brandschutz KW - Structural fire protection KW - Computertomographie KW - Computed tomography KW - Hochleistungsbeton KW - High performance concrete KW - Messtechnik KW - Mikrorisse KW - Micro cracks KW - Polypropylen-Fasern KW - Polypropylene fibres KW - PP-Fasern KW - Prüfmethoden KW - Rasterelektronenmikroskopie KW - Scanning electron microscopy KW - Risse KW - Schallemissionsanalyse KW - Acoustic emission KW - UHPC KW - Baustoffe KW - Brandschutz KW - Versuche PY - 2012 DO - https://doi.org/10.1002/best.201200024 SN - 0005-9900 SN - 1437-1006 VL - 107 IS - 7 SP - 476 EP - 483 PB - Ernst CY - Berlin AN - OPUS4-26174 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weise, Frank A1 - Onel, Yener A1 - Goebbels, Jürgen T1 - Analyse des Gefüge- und Feuchtezustandes in mineralischen Baustoffen mit der Mikro-Röntgen-3D-Computertomografie JF - Bauphysik KW - Beton KW - Naturstein KW - Schadensanalyse KW - Innovative Prüftechnik PY - 2007 SN - 0171-5445 SN - 1437-0980 VL - 29 IS - 3 SP - 194 EP - 201 PB - Ernst CY - Berlin AN - OPUS4-15688 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ruedrich, J. A1 - Rieffel, Y. A1 - Pirskawetz, Stephan A1 - Alpermann, H. A1 - Joksch, U. A1 - Gengnagel, C. A1 - Weise, Frank A1 - Plagge, R. A1 - Zhao, J. A1 - Siegesmund, S. T1 - Development and assessment of protective winter covers for marble statuaries of the Schlossbrücke, Berlin (Germany) JF - Environmental earth sciences N2 - The present study documents the results of an inter-disciplinary model project that was planned with the aim of developing an innovative winter covering system for marble statuaries located on the Schlossbru¨cke (Berlin). Such a system would need to fulfil the various requirements for structural stability, aesthetics, climate and practical use. This applied research represents the first complex scientific study of the sustainability of a winter covering system. The study is characterised by the use of complex scientific instruments such as special laboratory analysis and numerical simulation tools. The interaction between the environment and the artefacts in connection with the innovative winter covering structures were studied by extensive climatic monitoring. KW - Marble sculptures KW - Marble weathering KW - Winter cover KW - Climate data KW - Numerical simulations PY - 2011 DO - https://doi.org/10.1007/s12665-010-0765-2 SN - 1866-6280 SN - 1866-6299 VL - 63 IS - 7-8 SP - 1823 EP - 1848 PB - Springer CY - Berlin; Heidelberg AN - OPUS4-22363 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weise, Frank A1 - Maier, Bärbel A1 - Ehrig, Karsten T1 - Analyse der durch Frost- und Frost-Tausalz-Wechsel induzierten Schädigungsprozesse in Beton - Einsatz innovativer Prüftechniken JF - Beton- und Stahlbetonbau KW - Beton KW - Frost- und Frost-Tausalz-Prüfung KW - CIF- und CDF-Prüfung KW - Röntgen-3D-CT KW - Photogrammetrie PY - 2012 DO - https://doi.org/10.1002/best.201200056 SN - 0005-9900 SN - 1437-1006 VL - 107 IS - 12 SP - 1 EP - 8(?) PB - Ernst CY - Berlin AN - OPUS4-27040 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weise, Frank A1 - Voland, Katja A1 - Pirskawetz, Stephan A1 - Meinel, Dietmar T1 - Analyse AKR-induzierter Schädigungsprozesse in Beton - Einsatz innovativer Prüftechniken JF - Beton- und Stahlbetonbau KW - Beton KW - Frost- und Frost-Tausalz-Prüfung KW - CIF- und CDF-Prüfung KW - Röntgen-3D-CT KW - Photogrammetrie PY - 2012 DO - https://doi.org/10.1002/best.201200049 SN - 0005-9900 SN - 1437-1006 VL - 107 IS - 12 SP - 1 EP - 11(?) PB - Ernst CY - Berlin AN - OPUS4-27041 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weise, Frank A1 - von Werder, Julia A1 - Manninger, Tanja A1 - Maier, Bärbel A1 - Fladt, Matthias A1 - Simon, Sebastian A1 - Gardei, Andre A1 - Höhnel, Desirée A1 - Pirskawetz, Stephan A1 - Meng, Birgit T1 - A multiscale and multimethod approach to assess and mitigate concrete damage due to alkali-silica reaction JF - Advanced engineering materials N2 - Alkali-silica reaction (ASR) is a chemical reaction within concrete which can lead over time to cracking and spalling. Due to the complexity of the problem, it still causes damage to concrete constructions worldwide. The publication aims to illustrate the interdisciplinary research of the German Federal Institute for Materials Research and Testing (BAM) within the last 20 years, considering all aspects of ASR topics from the macro to the micro level. First, methods for characterization and assessment of ASR risks and reaction products used at BAM are explained and classified in the international context. Subsequently the added value of the research approach by combining different, preferably nondestructive, methods across all scales is explained using specific examples from a variety of research projects. Aspects covered range from the development of new test-setups to assess aggregate reactivity, to analysis of microstructure and reaction products using microscopical, spectroscopical and X-ray methods, to the development of a testing methodology for existing concrete pavements including in-depth analysis of the visual damage indicator and the de-icing salt input using innovative testing techniques. Finally, research regarding a novel avoidance strategy that makes use of internal hydrophobization of the concrete mix is presented. KW - Mitigation strategies KW - Concrete KW - Damage analysis KW - Alkali silica reaction KW - Road pavement KW - Accelerated testing KW - Non-destructive testing KW - Microstructure PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:101:1-2022052515100075090235 DO - https://doi.org/10.1002/adem.202101346 SN - 1527-2648 VL - 24 IS - 6 SP - 1 EP - 36 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54951 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pistol, Klaus A1 - Weise, Frank A1 - Meng, Birgit A1 - Diederichs, U. T1 - Polypropylene fibres and micro cracking in fire exposed concrete JF - Advanced materials research N2 - Though, concrete in general is a non-combustible building material, modern High Performance Concrete (HPC) is very susceptible to violent explosive spalling during a fire attack. This requires protective measures for fire safety design of concrete structures. The current most worthwhile method to prevent explosive spalling is the addition of monofilament Polypropylene fibres (PP-fibres). However, since it has become common knowledge that PP-fibres are suitable for fire safety design, a variety of theories concerning the mode of action of PP-fibres have been suggested. The present article summarizes the most important hypothesis and presents an innovative method for the analysis of micro structural processes in heated specimens. The results show that due to the thermal decomposition of PP-fibres capillary channels are created. Simultaneously, a netlike micro crack formation occurs, which connects these capillary channels. This enables the relief of internal stresses (mechanical effect) and the formation of a permeable transport system for the escaping water vapour (permeation effect). KW - Concrete KW - Fire Spalling KW - Micro-Crack KW - Polypropylene Fibres PY - 2014 DO - https://doi.org/10.4028/www.scientific.net/AMR.897.284 SN - 1022-6680 SN - 1662-8985 VL - 897 SP - 284 EP - 289 PB - Trans Tech Publ. CY - Zurich AN - OPUS4-30383 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -