Microbial induced calcite precipitation on macrostructural properties of concrete: a review

Microbially Induced Calcite Precipitation (MICP) has emerged as a promising bio‑based technique for enhancing the macrostructural performance of concrete. This review first outlines the underlying mechanisms of MICP, emphasizing the roles of ureolytic and non‑ureolytic bacteria in facilitating in‑situ calcium carbonate precipitation within cementitious matrices. Treatment efficiency is shown to depend on microbial strain selection, nutrient composition, curing conditions, and dosage optimization. Reported performance improvements are substantial: compressive strength typically increases by 20–50%, flexural strength by 19–66%, and tensile strength by 30–63%. Durability is also enhanced, with water absorption reduced by 15–31%, permeability decreased by 44–55%, and resistance to sulphate attack and freeze–thaw cycles notably improved. Beyond structural gains, MICP offers potential for self‑healing, crack mitigation, and environmental benefits such as carbon sequestration. However, existential challenges include non-uniform calcite distribution, limited long‑term durability under aggressive exposure, scalability and cost setbacks. This paper synthesizes current advancements, observed performance trends, practical limitations, and future research directions for integrating MICP into next‑generation sustainable concrete technologies.