Modelling strains of concrete exposed to alkali-silica reaction in variable hygro-thermal conditions

A mathematical model of combined action of hygro-thermal, chemical and mechanical loads is proposed to describe chemical degradation of concrete due to ASR. The model is based on mechanics of multiphase reactive porous media. The mass-, energy- and momentum balance equations, as well as constitutive and physical relationships necessary for modelling the ASR in variable environmental conditions, are presented. A method for their numerical solution with the finite element and finite differences methods is described. The proposed mathematical model is validated by comparing the simulation results with some published experimental data concerning hygro-thermal processes and ASR expansion of concrete specimens in different hygro-thermal conditions, both constant and variable in time.