Although portland cement is a commonly used civil infrastructure material, its production requires a significant amount of energy, which translates into a higher carbon footprint. Recent studies have identified that the use of micro-organisms has the potential of enhancing the compressive strength and durability of mortar; evaluation of the same was the objective of this study. To evaluate the influence of micro-organisms, Bacillus pasteurii bacteria and fly ash (which creates an optimum environment for bacterial growth) were used to prepare mortar specimens, and their compressive strength and durability were evaluated and compared with conventional mortar. The test results indicated that the mortar prepared with fly ash (5% of cement content by weight) and micro-organ¬isms (both in wild and mutated form) improved the compressive strength and durability of mortar. In addition, micro-level tests were performed, which further confirmed the positive influence of micro-organisms.
