The performance evaluation of protection barriers in bacterial self-healing mortar

The early age microcracking is a significant problem in concrete structures resulting in increased permeability and decreased durability. The previous work showed that Sporasarcina pasteurii cells immobilized on natural minerals such as bentonite, diatomaceous earth, sepiolite, and pumice effectively remediated early-age microcracks in the cementitious systems by triggering microbial-induced calcite precipitation (MICP). This promising approach can solve early-age shrinkage cracking in cementitious systems. Therefore, it is essential to assess the impact of self-healing additives on drying shrinkage. This study investigates the influence of mineral-based biological additives on the drying shrinkage capacity of cement-based mortar and the possible self-healing of cracks if any occur. To achieve this goal, the free shrinkage in control (containing only minerals) and bacterial (containing bio-based additive) samples were measured based on ASTM 596-18 norms. Moreover, the performance assessment of developed self-healing additives was done by determining compressive strength and initial setting time of bacterial self-healing mortar