Development of pore water pressure during freeze-thaw cycles in weather conditions

To assess the risk of frost damage to building materials, the mechanisms of pressure development in a material due to freezing under weather conditions should be adequately understood. In this study, we have demonstrated the evolution of pore water pressure in a brick wall during cyclic freezing and thawing caused by changes in air temperature and solar radiation. We developed a coupled hygrothermal and mechanical model of brick walls based on the theory of poromechanics. The calculation results showed that the water pressure in a south facing wall increases significantly during the night in a cold region. For a south facing wall, the surface thaws during the day due to solar radiation and freezes again at night, while the interior remains frozen throughout the day. We conclude that such incomplete freeze-thaw cycles in the weather conditions are much more damaging to building materials than a monotonous repetition of complete freezing and thawing.