Bacteria-based self-healing concrete: Effects of environment, exposure and crack size

The effect of water-borne contaminants on the durability of concrete is well-known and cracked concrete is more susceptible to permeation of these contaminants. An approach to autonomic self-healing of such concretes is the utilization of microbiologically-induced calcite-precipitation. This approach uses the metabolic activity of bacteria and biomineral precursors embedded within the concrete to form an inorganic material, usually calcite, as the healing compound. However, bacteria-based healing of concrete creates a number of scientific and engineering challenges at the biology-concrete technology interface. This paper provides a review of previous and on-going research on the use of bacteria-based self-healing of concrete in relation to the problems associated with the setting, hardening and carbonation of concrete and the problems associated with healing large cracks.