Numerical simulation of self-healing process and its application

The self-healing capacity of cementitious composites, i.e. their capacity to completely or partially re-seal cracks, is investigated with reference to an experimental campaign dealing with a normal strength concrete. Performing three-point-bending tests up to controlled crack opening and up to failure, respectively before and after exposure/conditioning, the recovery of stiffness and stress bearing capacity has been evaluated. The self-healing is numerically simulated using the computational model for concrete, SMM (Solidification-Microprestress-Microplane model), which makes use of a modified microplane model M4 and the solidification-microprestress theory. The moisture and heat fields, as well as, the hydration degree are obtained from the solution of the hygro-thermal-chemical problem. This model is extended to incorporate the self-healing processes, such as the delayed cement hydration, which is one of the main cause of the self-healing for young concrete, as well as the effects of cracking on the diffusivity and the opposite repairing effect of the self-healing on the microplane model constitutive laws. A numerical example is presented in order to validate the proposed computational model.