Thermo-hydric analysis of concrete–rock bilayers under fire conditions

High temperatures due to fire are amongst the most critical situations to which concrete may be exposed. For safety purposes, it is important to understand and preview the consequences of fire on the structural integrity of concrete. Concerning high temperatures, the mechanical degradation suffered by a concrete structure is related both to energy and mass transport. Therefore, a realistic modeling of such a condition shall take into account not only a thermal analysis but also the complex physical–chemical reactions developed among the components of that heterogeneous material. This approach is adopted in the present study as an effort to better reproduce the consequences of fluid flow and chemical processes – cement hydration and dehydration – in the material. cal simulations of the hygro-thermal behavior of concrete–rock bilayers subjected to fire conditions are performed through a transient and nonlinear model. The adopted model was evaluated by comparisons with data from an experimental program concerning thermal tests on a set of concrete–rock bilayer specimens, aiming to reproduce real world situations observed in some structures, such as tunnels.