Modeling evolution of frost damage in fully saturated porous materials exposed to variable hygro-thermal conditions

•Frost-induced damage of concrete was simulated using the delayed damage approach.•Thermodynamic model of kinetics of water freezing/melting in porous materials was presented.•Volume averaging procedure was applied to calculate the mean crystallization pressure exerted on the deteriorating solid skeleton.•The effective stress principle is applied to account for the crystallization pressure.•FEM and FDM were exploited to solve mass, energy and momentum balance equations.

Frost damage due to cyclic water freezing/ice thawing in the pores of building materials, is one of the main reasons jeopardizing durability of the structures in cold climates. A novel mathematical model of coupled hydro-thermo-mechanical phenomena in fully saturated porous materials exposed to water freezing/melting processes is proposed. The crystallization pressure, exerted by ice on the material pore walls and the related frost damage are considered. The kinetics of freezing/thawing phase change is modeled by means of a non-equilibrium approach. This kinetic description of the phase transformation allows avoiding numerical problems due to the strong sources of heat/mass accompanying the process. The frost deterioration is modeled by means of the isotropic nonlocal delayed damage theory in its rate formulation. The model equations are solved numerically by means of the finite element method in space and finite differences method in time. Three examples are solved to analyze the numerical performance of the model, to validate it by comparison with experimental results, and to present its application for modeling frost damage of a saturated concrete wall during cyclic freezing–thawing.