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 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 - JOUR A1 - Huismann, Sven A1 - Weise, Frank A1 - Meng, Birgit A1 - Schneider, U. T1 - Transient strain of high strength concrete at elevated temperatures and the impact of polypropylene fibers N2 - This paper presents the results of an experimental study on the transient strain of high strength concrete (HSC) under heating up to 750 °C and the impact of polypropylene (PP) fibers. Concerning this topic only few results are available in the literature and systematic investigations are missing. However, basic knowledge is necessary for the understanding of the internal damage processes in the material as well as for heated structures. The transient strain during heating can be separated in two basic components: the free thermal strain and the mechanical strain. They were experimentally determined exemplarily for one HSC. For the determination of the mechanisms of transient strain and particularly the influence of PP fibers different techniques were applied. In this context the monitoring of the microcracking was done for the first time with acoustic emission analysis in combination with ultrasonic measurements. This new approach helps fundamentally to explain the impact of PP fibers on free thermal strain and mechanical strain during heating up. Furthermore weight loss measurements were carried out to characterize the moisture transport. It was shown that the PP fibers cause an acceleration of the moisture transport in the temperature range from 200 to 250 °C which leads to drying shrinkage in opposite direction to the free thermal strain. Hence this paper is a contribution to the general understanding of the impact of PP fibers in HSC at high temperatures and emphasizes the important influence of PP fibers on the thermal and mechanical induced strain of HSC. KW - High strength concrete KW - Polypropylene fibers KW - Elevated temperatures KW - Transient strain KW - Acoustic emission KW - Ultrasound PY - 2012 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 - CONF A1 - Huismann, Sven A1 - Korzen, Manfred A1 - Weise, Frank A1 - Meng, Birgit ED - Rogge, A. ED - Meng, B. T1 - Betonabplatzungen unter Feuerangriff und der Einfluss von Polypropylenfasern auf die Mikrorissbildung T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Germany DA - 07.11.2011 PY - 2011 SN - 978-3-9814281-0-0 SP - 163 EP - 171 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-25185 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Huismann, Sven A1 - Korzen, Manfred A1 - Rogge, Andreas ED - Rogge, A. ED - Meng, B. T1 - Stahlbetonstützen aus hochfestem Beton unter Brandbeanspruchung und die Anwendung allgemeiner Rechenverfahren T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Germany DA - 07.11.2011 PY - 2011 SN - 978-3-9814281-0-0 SP - 154 EP - 162 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-25186 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Huismann, Sven A1 - Korzen, Manfred A1 - Rogge, Andreas T1 - Tragverhalten von Stützen aus hochfestem Stahlbeton unter Brandbeanspruchung T2 - 52. DAfStb-Forschungskolloquium, BAM CY - Berlin, Germany DA - 2011-11-07 PY - 2011 AN - OPUS4-25239 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Huismann, Sven A1 - Weise, Frank A1 - Meng, Birgit A1 - Schneider, U. T1 - Influence of polypropylene fibres on the thermal strain of high strength concrete at high temperatures N2 - This paper presents the results of an experimental study on the influence of polypropylene (PP) fibres on the thermal strain of high strength concrete (HSC) at temperatures up to 750°C. Concerning this topic only few results can be found in the literature and systematic investigations are missing. However, basic knowledge is necessary to understand the internal damage processes as well as for structural design. To explain the differences in the thermal strain of HSC with and without addition of PP fibres the internal damage processes were investigated with acoustic emission (AE) analysis and ultrasound (US). Furthermore the weight loss was measured continuously during heating to monitor the drying of the specimen. This novel approach by combining these different methods with strain measurements at high temperatures allows the integral description of the internal damage processes. The results reveal significant differences in the thermal strain of HSC when PP fibres are added. Between 200°C and 250°C the thermal strain of HSC with PP fibres is superimposed by shrinkage caused by accelerated drying. Above 250°C it is lower than that of plain HSC without PP fibres. It is supposed that it is caused by a more homogeneous distribution of micro cracks whereby the fibre beds acting as defects in the concrete. Hence this paper gives a contribution to the general understanding of the impact of PP fibres in HSC at high temperatures and points out the influence of the fibres on the thermal strain of HSC. KW - High performance concrete KW - High temperatures KW - Polypropylene fibres KW - Thermal strain KW - Acoustic emission KW - Ultrasound PY - 2011 DO - https://doi.org/10.1260/2040-2317.2.3.173 SN - 2040-2317 VL - 2 IS - 3 SP - 173 EP - 179 PB - Multi-Science Publ. Co. CY - Brentwood AN - OPUS4-24817 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pereira, F. A1 - Pistol, Klaus A1 - Korzen, Manfred A1 - Weise, Frank A1 - Pimienta, P. A1 - Carré, H. A1 - Huismann, Sven ED - Koenders, E.A.B. ED - Dehn, F. T1 - Monitoring of fire damage processes in concrete by pore pressure and acoustic emission measurements N2 - This paper presents the combined use of acoustic emission (AE), gas pore pressure and temperature measurements (PT). The simultaneous application of both techniques represents a new methodology in the context of fire spalling and contributes to a better understanding of the mechanisms of fire spalling, particular with regard to the interaction of micro cracking and pore pressure evolution. The study presents fire tests on normal strength concrete specimens with and without reinforcement at ISO Standard fire and at hydrocarbon (HC) fire. Supported by AE-analysis, it can be shown that due to the higher heating rate of the HC-fire in comparison to the ISO Standard fire the damage processes inside the concrete during the exposure are increased combined with augmenting the concrete permeability. As a consequence lower pore pressures were measured. However, despite the lower pore pressures, explosive spalling was observed. T2 - 2nd International RILEM workshop on concrete spalling due to fire exposure CY - Delft, The Netherlands DA - 05.10.2011 KW - Ordinary concrete KW - High temperature KW - Gas pore pressure KW - Acoustic emission KW - Spalling PY - 2011 SN - 978-2-35158-118-6 SP - 69 EP - 77 PB - RILEM Publications AN - OPUS4-24818 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Huismann, Sven T1 - Damage of a high performance concrete at high temperatures due to thermo-mechanical stresses T2 - 7th International PhD Symposium in Civil Engineering CY - Stuttgart, Germany DA - 2008-09-11 KW - High performance concrete KW - Fire KW - High temperatures KW - Cracking KW - Thermo-mechanical stresses PY - 2008 IS - Kap. 16.3 SP - 23 EP - 29 AN - OPUS4-17950 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Huismann, Sven A1 - Korzen, Manfred A1 - Rodrigues, J.P.C. T1 - Damage and strenght reduction of high performance concrete due to thermomechanical stresses T2 - Fire Design of Concrete Structures - From Materials Modelling to Structural Performance, Workshop CY - Coimbra, Portugal DA - 2007-11-08 PY - 2007 AN - OPUS4-15489 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Huismann, Sven T1 - Damage of high performance concrete at high temperatures due to thermo-mechanical stresses T2 - 7th fib International PhD Symposium in Civil Engineering, Universität Stuttgart CY - Stuttgart, Germany DA - 2008-09-11 PY - 2008 AN - OPUS4-17197 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -