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. (C) 2007 Elsevier B. V. All rights reserved.