Computational homogenization of micro-structural damage due to frost in hardened cement paste

Based on a micro-structural finite-element model using computer-tomography scans at micrometer length-scale, damage due to frost within hardened cement paste (HCP) is evaluated. In order to verify the microscopic constitutive equations, a multi-scale model is introduced which allows a comparison with experimental data at macro-level. Subsequently, damage due to frost is simulated numerically: the water-filled pores of HCP increase in volume during a freezing process which yields an inelastic material behavior. Numerical simulations at micro-structural level are performed for different moistures and temperatures, and an effective correlation between moisture, temperature and the inelastic material behavior is obtained. Finally, thermo-mechanical coupling is introduced and an effective constitutive equation for HCP is developed using the abovementioned temperature-moisture-damage correlation.