A Non-Equilibrium Micromechanics-Based Thermo-Hydro-mechanical Model for Freezing/thawing in Saturated Cementitious Materials: from Elasticity to Elastic-Plasticity

To understand the freeze-thaw behavior of saturated cementitious materials (CMs), a novel micromechanics-based thermo-hydro-mechanical (THM) model is proposed. In this model, a non-equilibrium approach is developed to capture water freezing/melting considering pore size distribution (PSD), supercooling, and freeze-thaw hysteresis. In addition, a micromechanical upscaling approach is presented to take frost damage, residual deformation, and the influence of microstructure into account. Comparisons with experimental results validate and highlight the capabilities of the proposed model. The model sheds light on the quantitative effects of the material properties and liquid boundaries on the freeze-thaw behavior. The results show that residual deformation significantly affects the freeze-thaw behavior including the hydraulic pressure and frost damage. Moreover, the important phenomena of CMs on the structural scale in cold regions including frost heave and thaw settlement, freezing fronts, and frost damage layer can be well reproduced, which suggests the present model has good potential for engineering use.