Repeated Autogenous Healing in Strain-Hardening Cementitious Composites by Using Superabsorbent Polymers

Autogenous healing is an already-present feature in strain-hardening cementitious materials, but it is an inferior mechanism because it can only heal small cracks in the presence of water. A cementitious material with synthetic microfibers and superabsorbent polymers (SAPs) could provide a solution. In this study, the ability of repeatable promoted autogenous healing in fiber-reinforced, strain-hardening cementitious materials with and without SAPs is investigated by comparing their mechanical properties after they are subjected to two cycles of loading under a four-point-bending test. The results indicate that SAP particles promote self-healing. The main mechanisms of the autogenous healing are the hydration of unhydrated cementitious materials in cracks and the precipitation of calcium carbonate on the crack faces. The healed specimens are able to regain some of their mechanical properties (up to 75%). Even second reloading of those healed samples leads to partial additional regain in mechanical properties (up to 66%).