Characterisation of autogenous healing in cracked mortars under marine water exposure

Abstract

In this study, autogenous crack healing was quantified in mortar specimens under various exposure conditions. Specimens were cracked at 28 days and then exposed to a single type of environment: submersion in freshwater, submersion in marine water or cyclic submersion in marine water followed by drying daily (tidal conditions). Instead of taking measurements at a few selected points along the crack length, crack widths were innovatively determined through periodic measurements monitoring the entire crack surface profile. This enabled the identification of significant variations in the healing profile and evidence of widening mostly due to spalling. Specimens exposed to submerged marine conditions displayed maximum overall healing and were able to completely heal a higher percentage of cracks as wide as 0.72 mm as compared to the 0.6 mm reported in previous studies. Evidence of crack widening due to spalling was found in the crack profiles, and the phenomenon was shown to be dependent on the initial width, with wider cracks showing less absolute widening. Specimens exposed to tidal conditions showed the least crack widening among all exposure conditions.