Micromechanical modeling of frozen concrete by micro-deformation of multi-phase composite material

Abstract

Concrete is a heterogeneous multi-phase composite material, and the frozen damage is one of the key factors for the deterioration of concrete. In this paper, a micro-scale modeling framework for frozen damage of concrete was established by the micro-deformation of multi-phase composite material, which can be used to investigate the deterioration process in concrete accounting for its micro-structural characteristics. Based on the crystallization thermodynamics and ice formation theory, the calculation method was developed by the phase transformation on materials of concrete, which predicts the pore evolution behavior and macro-mechanical evolution of concrete with freeze–thaw cycles (FTCs). The calculation results indicate that calculation model predictions agree well with the test results. For concrete with fewer FTCs, the material performance degradation of concrete is mainly stiffness degradation, the increase of total porosity comes from the increase of gel pores. For concrete with more FTCs, the increase of gel pores slowed down, and the proportion of air voids and capillary pores increased significantly, which gradually reduce the strength of concrete.