Autogeneous self healing of High Performance Fibre Reinforced Cementitious Composites

In this paper the results are shown of a thorough characterization of the self-healing capacity of High Performance Fibre Reinforced Cementitious Composites (HPFRCCs). In detail, the capacity of the material to completely or partially re-seal cracks will be investigated, as a function of its composition, maximum crack opening and exposure conditions. The topic has been investigated including the effect of different flow-induced alignment of fibres, which can result into an either a strain hardening or softening behaviour, whether the material is stressed parallel or perpendicularly to the fibres. Specimens were initially pre-cracked in 4-point bending and up to different values of crack openings, and submitted to different exposure conditions, including water immersion, exposure to humid or dry air, and wet-and-dry cycles. After scheduled exposure times, from one to six months, specimens were tested up to failure according to the same test set-up and outcomes of the self-healing, if any, were quantified in terms of recovery of stiffness, strength and ductility. In a durability-based design framework, self-healing indices to quantify the recovery of mechanical proper-ties were also defined and their significance checked.