Effect of super absorbent polymer and mineral additives on mechanical, shrinkage and healing properties of self-healing lightweight aggregate concrete under different curing regimes

Super absorbent polymers, which allow better moisture retention within cracks for extended periods, can be beneficial in facilitating the autogenous self-healing process of concrete incorporated with carbonate-built lightweight aggregates. In the present study, the combined effect of super absorbent polymers and mineral ad-ditives, the calcium source provider, on the self-healing properties of self-healing lightweight concrete was investigated. In addition to determining the effect on compressive strength and drying shrinkage, a destructive test by flexural strength and a non-destructive test through electrical impedance spectroscopy were conducted to evaluate self-healing efficiency under different curing regimes. The results showed that the strength was increased by adding mineral additives, while it decreased with increasing the dosage and size of super absorbent polymers. In addition, the application of super absorbent polymers has significantly improved the healing effi-ciency, especially by 56.1% with adding the large size of super absorbent polymers in the wet-dry cycle. Furthermore, through the analysis of electrical impedance spectroscopy, the super absorbent polymers of large particle size were proved to have excellent moisture retention within cracks in the wet-dry cycles. According to microscopic observation, the potential mechanism was proposed that the swollen super absorbent polymers were possible to further improve self-healing efficiency in the wet environment.