Numerical modeling of leaching-precipitation processes in non-isothermal partially saturated cementitious materials

A general approach to modeling leaching-precipitation processes in cement based materials, due to combined action of variable hydro-thermal, chemical and mechanical loads, is presented. Mechanics of multiphase porous media and damage mechanics are applied for this purpose, and kinetics of degradation processes is described with evolution equations based on thermodynamics of chemical reactions. The mass-, energy- and momentum balances, as well as the evolution equations and some constitutive relations are briefly summarized. Then, the model governing equations are numerically solved with the finite element method. Two examples of the model application for analyzing chemical degradation processes of cement based materials are presented and discussed. The first one deals with the salt crystallization during drying of a concrete wall, and the second one concerns calcium leaching from a concrete plate due to chemical attack of pure water at two different temperatures.