Modelling and simulations of the chemo–mechanical behaviour of leached cement-based materials: Leaching process and induced loss of stiffness

The present paper aims at modelling the decalcification process in cement-based materials and its impact on the material stiffness, which represents a serious matter in terms of long-term durability. The resistance of cementitious materials to this chemical alteration is strongly conditioned by their mineral composition and porosity. For this purpose, a multi-scale homogenization approach (Stora et al., Trans. Por. Med. 73, 3, 2008) is implemented in the numerical platform ALLIANCES (P. Montarnal, C. Mügler, J. Colin, M. Descotes, A. Dimier, E. Jacquot, Presentation and use of a reactive transport code in porous media, Phys. Chem. Earth 32, 2007) to estimate from these data the elastic and diffusive properties of cement-based materials. The association of this homogenization model and of the integration platform, which can couple different numerical codes, then allows for evaluating the evolution of the mineral composition and of the diffusive and mechanical properties of a concrete material during chemical deterioration processes. Simulations of pure water leaching of hydrated cement pastes are performed and the consequences of this decalcification on the material's residual elastic behaviour are estimated. The numerical results are confronted with available experimental data and analyzed. The simulations of the non-linear mechanical behaviour of leached cementitious materials taking into account interactions between damage and leaching is not reported here for conciseness but can be found in another document (Stora, Modelling and simulations of the chemo–mechanical behaviour of leached cement-based materials. PhD Dissertation, univ. of Paris-Est 2008).