A coupled hydro-chemo-mechanical approach to model the degradation and appearance of cracks in cementitious materials subject to carbonation

Abstract Coupled Thermal-Hydraulic-Mechanical-Chemical (THMC) approaches are crucial for assessing the durability of cementitious materials. We present a novel approach to overcome past limitations of THMC modelling and validate it based on experimental results of accelerated carbonation tests. Our numerical approach rests on a sequential coupling between Hytec and Cast3M. Hytec computes the evolution of hydraulic and mineralogical fields allowing to compute the micromechanical properties (e.g. Young modulus). The mineral reactions generate tensile stresses and Cast3M computes the associated strain tensors and the damage evolution represented by the opening or sealing of cracks, impacting subsequent reactive transport processes. Our approach manages to reproduce the crack patterns and non-uniform degradation depths observed on microtomographic images of carbonated cement samples, which can only be explained by the coupled dynamics of chemical and mechanical processes. Our approach can be extended to a wide range of cement-concrete pathologies and contexts.