Effect of improved autogenous mortar self-healing in the alkali-aggregate reaction

Abstract

This article evaluated the effect of improved autogenous mortar self-healing in the alkali-aggregate reaction (AAR). Prismatic mortar specimens were cast with different contents of polypropylene microfiber and crystalline admixture. The crack-induction method (for subsequent self-healing) was the AAR accelerated mortar bar test itself. After AAR-testing, the specimens were submitted to wetting and drying cycles to stimulate the self-healing mechanism. These two approaches (AAR and self-healing steps) were alternately repeated four times. The results showed that the reference mortar and the mixture with 1% of polypropylene microfiber had the highest and lowest levels of expansion, respectively. The expansion rate was lower for the combined mixtures, although the initial values of length change were high. The visual inspection confirmed that improved autogenous self-healing could close cracks caused by AAR and promote microstructural densification.