A novel strategy to assess healing induced recovery of mechanical properties(HIRMP) of strain hardening/engineering cementitious composites(SHCCs/ECCs) in autogenous healing

The crack-bridging effect of fibers in strain-hardening cementitious composites (SHCCs) restricts the crack width to a very small value, which promotes autogenous self-healing. The healing should lead to a noticeable recovery of mechanical properties. To ensure healing-induced recovery of mechanical properties (HIRMP) is relied upon in the built environment, a novel strategy for in-situ assessment of HIRMP is developed. HIRMP causes the stress strain response of healed specimen to be 'close' to that of the pre-damaged state. It was derived that the ratio of areas(ROA) under the stress-strain response between 'healed' and 'undamaged' state appropriately measures the 'closeness' between these stress-strain curves. Exploiting the fact, acoustic emission (AE) signals are associated with fracture energy (thus also with the area under stress-strain curve). We design novel damage parameters to statistically represent random-stochastic fracture processes in self-healed SHCCs. The ratio of these parameters was then utilized to estimate HIRMP. This strategy was then studied experimentally on self-healed SHCCs with a different healing environment, fiber content, and pre-damage level. The results computed from this strategy are more consistent and comprehensive as compared to the conventional technique. The predicted HIRMP matches well with the expectation over a long range of recoveries.