Self-healing Properties of Engineered Cementitious Composites (ECC)

Abstract

Concrete is the most widely used construction material globally; however, its brittle behavior makes it prone to cracking, negatively impacting the structural durability and sustainability of concrete infrastructure. The introduction of self-healing mechanisms into concrete that can promote healing of cracks with the material produced by the concrete could solve many of the strength degradation and durability issues associated with cracking seen in current concrete structures. Even though many mechanisms have been used to induce self-healing in cementitious material, the self-healing of Engineered Cementitious Composites (ECC) has proven to be one of the most efficient mechanisms, as it has shown the ability to achieve recovery of transport and mechanical properties. The present study investigates the self-healing properties of ECC. In phase I of this research, the focus is on the repeatability of self-healing mechanism in ECC. The aim is to determine the positive/negative effect of applying a compression cycle on partially healed cracks. In this phase, the recovery of mechanical properties is measured to represent the self-healing efficiency rate. In phase II of the research, the extent of self-healing in a favorable condition is evaluated. Crystalline Admixture (CA) is used in this phase to improve ECC's self-healing properties, and self-healing is measured through the recovery of transport properties. Since the surrounding environment has a significant impact on ECC's self-healing process, three exposure conditions of air dry, tap water and sea water were studied in this experiment. Final results proved that applying a compression cycle on the partially healed cracks reduces the self-healing efficiency. Both results in Phase I and Phase II suggest that sea water is as a favorable condition for self-healing of ECC.