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 JF - Journal of structural fire engineering 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 - Korzen, Manfred ED - Wald, F. ED - Horová, K. ED - Jirku, J. T1 - Constitutive equations for structural steel subjected to fire - some remarks T2 - International conference 'Applications of structural fire engineering' (Proceedings) N2 - Although identified on the basis of so-called instationaiy creep-tests the constifrvtive model of Eurocode 3 (EN 1993-1-2, 2010) - hereinafter refened to as EC3 - represents a non-linear rateindependent relationship between stress and meclianical strain. I.e. the experimentally observed phenomenou of creep at constant stress but linear time varying temperature is described only through the temperature dependence of the material parameters characterizing the EC3 constitutive model. As a consequence some important phenomena cannot properly be described: E.g. creep or relaxation at constant temperature, creep or relaxation at non-monotonic temperature rates or sensitivity of the instationary creep process on the temperatme rate. T2 - International conference 'Applications of structural fire engineering' CY - Prague, Czech Republic DA - 29.04.2011 KW - Constitutive equation KW - Thermal strain KW - Steel KW - Fire KW - Creep PY - 2011 SN - 978-80-01-04798-9 SP - 79 EP - 83 AN - OPUS4-23711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Huismann, Sven A1 - Weise, Frank A1 - Meng, Birgit A1 - Schneider, U. ED - Kodur, V. ED - Franssen, J.-M. T1 - Influence of polypropylene fibres on the thermal strain of high strength concrete at high temperatures T2 - 6th International conference "Structures in fire" (Proceedings) T2 - 6th International conference "Structures in fire" CY - East Lansing, Michigan, USA DA - 2010-06-02 KW - High performance concrete KW - High temperatures KW - Polypropylene fibres KW - Thermal strain KW - Acoustic emission KW - Ultrasound PY - 2010 SN - 978-1-60595-027-3 SP - 719 EP - 726 PB - DEStech Publications, Inc. CY - Lancaster, PA, USA AN - OPUS4-21563 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -