Self-healing ability of fly ash–cement systems

Concrete is susceptible to cracking due to both autogenous and drying shrinkage. Nevertheless, most of these types of cracks occur before 28 days. Because fly ash continues to hydrate after 28 days, it is likely that hydrated products from fly ash may modify microstructure, seal these cracks, and prolong the service life. This research investigates the self-healing ability of fly ash–cement paste. Compressive strength, porosity, chloride diffusion coefficients, hydration reactions and hydrated products were studied. The research focuses on behavior after 28 days. According to the experimental results, the fly ash–cement system has the self-healing ability for cracks that occur from shrinkage. The self-healing ability increased when the fraction of fly ash increased.