Engineering self healing capacity of cement based materials through crystalline admixtures

In this paper aims a thorough characterization will be performed of the effects of crystalline admixtures, currently employed as porosity reducing admixtures, on the self-healing capacity of the cementitious composites, i.e. their capacity to completely or partially re-seal cracks and, in case, also exhibit recovery of mechanical properties. The problem will be investigated with reference to both a Normal Strength Concrete (NSC) and a High Performance Fiber Reinforced Cementitious Composite (HPFRCC). In the latter case the influence of flow-induced fiber alignment will also be considered in the experimental investigation. With reference to either 3-point (for NSC) or 4-point (for HPFRCC) bending tests performed up to controlled crack opening and up to failure, respectively before and after exposure/conditioning, the recovery of stiffness and stress bearing capacity will be evaluated to assess the self-healing capacity. Moreover, in a durability-based design framework, suitable self-healing indices to quantify the recovery of mechanical properties will be defined.