Effect of Fly Ash Contents in Autogenous Self-Healing of Conventional Concretes Analyzed Using Different Test Tools

Abstract

Concrete structures are susceptible to cracking, contributing to the penetration and transport of deleterious agents, which may compromise their durability. At the end of the 19th century, a natural capacity of the concrete in sealing cracks was noted, which would later be called autogenous self-healing. This article aims to explore the effect of fly ash contents in autogenous self-healing of conventional concretes using different test tools. Therefore, the durability of the material was indirectly assessed. The age of cracking was also analyzed. Concrete specimens with different fly ash contents (0%, 12%, and 27%) were cracked by compression at 7 and 28 days. Subsequently, durability tests were performed on the day of cracking and after 84 days under wetting and drying cycles to stimulate self-healing mechanisms. The results demonstrated the beneficial effects of self-healing on concrete containing fly ash when the analyzed parameter is more focused on the concrete bulk of the test specimens (ultrasonic pulse velocity and resistance to chloride ingress). When the analyzed parameter is related to the surface of the specimens (resistance to carbonation), the effect of cracking is more evident in concrete without fly ash.