A phase-field approach for portlandite carbonation and application to self-healing cementitious materials

A conceptual phase-field model is proposed for simulating complex microstructural evolutions during the self-healing process of cementitious materials. This model specifically considers carbonation healing mechanisms activated by means of dissolution of soluble Ca(OH) 2 mineral and precipitation of the CaCO 3 self-healing product. The system is described by a set of conservative and non-conservative field variables based on a thermodynamic analysis of the precipitation process and realised numerically using the finite element method (FEM). As a novel concept for modeling self-healing of cementitious materials, the evolution of multiple interfaces was investigated and demonstrated on a simple experimental test case of a self-healing mechanism consisting of carbonating calcium hydroxide. Parametric studies were performed to numerically investigate the effect of chemo-physical conditions. Two representative practical examples of cementitious materials were numerically implemented. It is demonstrated that the simulated evolution of the crack morphology is in good qualitative agreement with the experimental data.