Performance of Self-healing Cementitious Mortar with PVA Fiber and SAP

Although concrete materials generally exhibit outstanding mechanical properties, it is susceptible against crack formation. It has been reported that narrow cracks (≤ 150 µm) could be naturally sealed in the cement matrix by externally supplied water-induced hydration. However, the crack width of larger than 150 µm is difficult to be sealed without using additional self-healing admixture. In this study, the self-healing cementitious mortar was successfully developed by using a combination of polyvinyl alcohol (PVA) fiber and superabsorbent polymer (SAP), aiming to heal the wide cracks. Although the mechanical properties were slightly reduced, it shows outstanding self-healing performance by using the dual admixtures. A self-healing rate of 60% was observed in the control sample with an initial crack width of 300 µm, while a self-healing rate of nearly 100% was confirmed with suitable SAP and PVA. In addition, it was confirmed that lower hydration degree of self-healing mortar in early stage contributes to the enhanced self-healing performance of developed composite system by internally supplied water from SAP.