Coupled heat and water transport in deformable porous materials considering phase change kinetics

The paper considers water solidification in porous materials. The cement mortar microstructure and the content of ink-bottle type pores evolution due to cyclic water freezing was analyzed by means of mercury intrusion porosimetry. The influence of pressure, temperature and the size of pores on the equilibrium between solid and liquid water was investigated using Gibbs free energy. Mathematical model describing heat and water transport in deformable porous materials considering water phase change kinetics was proposed. The numerical code was developed using finite element, finite difference and Newton–Raphson methods. The model and the code was validated using experimental data considering the hysteresis of water freezing-ice thawing. The influence of water freezing in the squared concrete column on strain field was investigated as a second problem. It was shown that water solidification induces the swelling, which counteracts the thermal shrinkage. The comprehensive approach allows to investigate the transport processes together with the related phenomena and asses the durability of porous materials exploited in cold regions.