This paper focuses on mechanical regains that can be obtained due to self-healing of cementitious materials. Experimentally, small cracks with a width of around 10 μm were healed by water immersion and corresponding regains were assessed by means of three-point-bending tests. A general discussion about stiffness and strength regains is provided with the help of newly introduced indices. Besides, the first comprehensive finite element model to characterise the micro-mechanical properties of the healing products is introduced, based on the coupling of the microstructural hydration model CEMHYD3D and the finite element code Cast3M. The main objective is to analyse the healing potential and rate, as well as the nature of the healing products. The nature of the simulated healing products is in agreement with observation conducted using SEM/EDX on artificial cracks created at early age.