TY - CONF A1 - Klimek, André A1 - Hothan, Sascha A1 - Rogge, Andreas T1 - Investigation of Size Effects in Concrete Spalling T1 - Untersuchung des Maßstabseffekts auf das Abplatzverhalten von Beton T2 - Proceedings of the 6th International Workshop on Concrete Spalling due to Fire Exposure N2 - Spalling of concrete due to fire exposure can lead to severe damage of building components. It is a much discussed subject in structural engineering and not yet completely understood. Generally, it is assumed that thermohydraulic and thermomechanical processes induce tensile stresses in the concrete. Furthermore, the tensile strength of concrete is reduced due to increasing temperatures. The combination of an increasing tensile stress and a decreasing tensile strength result in the occurrence of explosive spalling. The spalling behaviour of concrete is influenced by many parameters, for instance the water cement ratio, porosity, permeability of concrete as well, the presence of steel reinforcement and polypropylene fibres, also the size and geometry of the fire exposed area. Within the current research project at Bundesanstalt für Materialforschung und prüfung (BAM), the susceptibility to spalling of six different concrete mixtures is analysed to quantify the size effect using small scale, intermediate scale and full scale tests. A special fire test setup was built to test specimens simultaneously to enable a better comparability. All specimens are tested without additional mechanical load and unrestraint to prevent external induced cracking at the fire exposed site. Thermocouples are used to measure in situ the temperature distribution as an indication on the thermal degradation of the concrete during the fire tests. Afterwards the maximum spalling depth and the damaged area of the specimen are illustrated by a photogrammetric measurement system. The contribution to the spalling workshop presents the results of four concrete mixtures tested in intermediate-scale and full-scale fire tests. The comparisons are based on the concrete temperature as well as the obtained photogrammetric data. The results show that the spalling depth and the spalling area are significantly affected by the size of the fire exposed area. T2 - 6th International Workshop on Concrete Spalling due to Fire Exposure CY - Sheffield, UK DA - 19.09.2019 KW - Concrete KW - Spalling KW - Fire Test KW - Photogrammetry KW - Size Effect PY - 2019 UR - https://firespallingworkshop2019.group.shef.ac.uk/wp-content/uploads/2019/09/Fire-Spalling-Workshop_Proceedings.pdf SN - 978-1-5272-4135-0 SP - 61 EP - 70 PB - The University of Sheffield CY - Sheffield AN - OPUS4-49254 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -