Crack healing performance of bacteria-based mortar under sustained tensile loading in marine environment

Abstract

Healing performance of bacteria-based mortar was evaluated under sustained axial tensile loading at 90% of the cracking load in submerged freshwater, submerged marine and tidal conditions. The bacteria-based mortar contained Halobacillus Halophilus bacteria, calcium lactate and expanded perlite aggregates. Loaded bacterial specimens showed 20%–30% less healing compared to unloaded ones. Crack widening due to creep under sustained loading decreased healing. Healing increased by 5% in bacterial specimens under tidal conditions when the loading level was reduced from 90% to 60%. Compared to control specimens, bacterial specimens enhanced healing by 14% under sustained loading in submerged marine conditions. However, bacteria had no noticeable impact on healing for specimens under sustained load in tidal conditions. Specimens in tidal conditions displayed 14%–25% less healing compared to those under submerged marine conditions. The reduced healing in tidal conditions was the result of deterioration of healing products under wet-dry cycles.