Concrete Subjected to Fire Loading

Tunnel fires demonstrate how the load-bearing§capacity of the structure is reduced by fire loading§which eventually leads to collapse of the tunnel. In§this work, different aspects of 'Concrete Subjected§to Fire Loading' are tackled. First, spalling of§near-surface layers of heated concrete is§investigated employing a high-speed camera. This§allows identification of the main processes§controlling spalling of concrete. In addition, the§permeability obtained from experiments on concrete§with or without polypropylene (PP) fibers is related§to the pore structure of heated concrete. This§highlights the effect of PP-fibers as well as of§additives and the production process on transport§properties of concrete under fire attack. Besides§experimental investigations, finite-element analyses§of heat and mass transport in heated concrete are§conducted. The obtained temperature and gas-pressure§results provide insight into the risk of spalling of§concrete for varying amount of PP-fibers. Finally, a§structural analysis tool is employed to investigate§the structural performance of a real tunnel structure§under different fire and spalling scenarios.