As heterogeneous material, concrete exhibits very complex behavior when exposed to elevated temperature. One of the important aspects is the load-induced thermal strain (LITS), which represents the difference between the thermal strain of non-loaded and loaded concrete. Even though a…
As heterogeneous material, concrete exhibits very complex behavior when exposed to elevated temperature. One of the important aspects is the load-induced thermal strain (LITS), which represents the difference between the thermal strain of non-loaded and loaded concrete. Even though a great amount of research has been performed so far, there is still no general consensus about the mechanism that leads to the change of thermal behavior when concrete is loaded in com- pression prior to heating. In the present paper, the thermal behavior of concrete is analyzed employ- ing 3D finite element code with temperature dependent microplane model as a material constitutive law. Concrete is modeled at mesoscale, whereby two cases are considered: (i) concrete as a compo- site of concrete mortar and aggregates and (ii) concrete as a composite of cement paste and aggre- gates. The approach is validated against experiments available from the literature. It is shown that the heterogeneous structure of concrete plays a crucial role in damage processes at elevated temper- ature and hence has a major influence on the thermal strain of loaded concrete.