Mesoscale approach to numerical modelling of thermo-mechanical behaviour of concrete at high temperature

Abstract

This article presents a lattice-type numerical modelling method for analysing the thermo-mechanical behaviour of concrete subjected to compressive stresses at high temperature. The concrete is considered as a two-dimensional mesoscale structure consisting of three material phases: aggregates, cement paste and interfacial transition zones (ITZ). Subjected to a high temperature, concrete might be damaged due to the differences in thermal expansion between these components. The damage results in the initiation and propagation of cracks that affect the thermal conductivity of the material and thus the heat transfer within the structure. A modified damage-elasticity model, coupled with a nonlinear heat transfer equation taking into account the damage induced thermal conductivity change, is implemented in the lattice framework to describe the thermo-mechanical behaviour of concrete. Comparison of the current study to experimental and numerical results reported in the literature indicates the significance of the proposed model.