Prediction of the thermal spalling risk of concrete structures during fire by means of a finite element model

A very characteristic mode of concrete damage at high temperature, especially for the materials characterized by a low intrinsic permeability, is the so called thermal spalling. In this work a mathematical model, which considers concrete as multiphase porous material, is applied to defining some spalling indexes based on various collapse mechanisms. A validation of the quantities proposed, carried out by means of a comparison with some experimental test results, is presented together with an integrated application of the model to the case of fire in tunnels. The latter calculation is solved by coupling the model for concrete with a CFD model for the simulation of fire evolution.