A discrete numerical model for the effects of crack healing on the behaviour of ordinary plain concrete: Implementation, calibration, and validation

In the last decade the self-healing of cracks in cementitious materials has been gaining an increasing interest by both the concrete industry and the scientific community. Framed into the Horizon 2020 project ReSHEALience, the present research work aims to formulate a proposal for the numerical modelling of autogenous and stimulated autogenous healing in ordinary plain cement-based materials, whose composition is enriched, in the latter case, with crystalline admixtures. In this paper a meso-scale discrete model that also considers the healing process is presented, relying on the coupling and the enhancement of two models: the Hygro-Thermo-Chemical model, for the simulation of chemical, moisture and heat transport phenomena, and the Lattice Discrete Particle Model, for the mechanical part. The evolution of the healing phenomenon is implemented into the HTC discrete formulation, in order to simulate the degree of crack closure over time. The latter is then employed to capture how the self-repairing affects both moisture permeability and mechanical performances. Finally, the results of a laboratory campaign, carried out at the Politecnico di Milano, are used for calibrating and validating the model presented.