Assessing compatibility of self-healing nutrients for microbially induced calcium carbonate precipitation in calcium aluminate cement

Microcrack formation in concrete poses a risk of durability degradation and ultimate failure of the structure. Calcium aluminum cements (CAC) are susceptible to significant early age microcrack formation due to their rapid setting behavior. Microbially-induced calcium carbonate precipitation (MICP) is a promising research frontier that delivers concrete self-healing capability upon the incorporation of specialized bacteria and nutrients into the cement mix. This study explored the applicability of bacteria-based self-healing technology to mitigate microcrack formation in CAC. The effect of self-healing nutrients such as urea, yeast extract and calcium lactate on the mechanical properties, phase assemblage and reaction kinetics of CAC were investigated. The results demonstrated that the incorporation of self-healing nutrients improved the compressive strength of the specimens by an order of magnitude, ranging from 21 to 97%. However, the reaction kinetics of CAC was delayed by 25 to 65 hours with the incorporation of yeast extract and calcium lactate. • Applicability of bacteria based self-healing in CACs was Investigated. • The effects of self-healing nutrients on the mechanical properties, phase assemblage, and reaction kinetics of CAC were examined. • Nutrients enhanced the compressive strength of CAC. • Dissolution of CAC was limited due to the addition of yeast extract and calcium lactate. • Addition of yeast extract and calcium lactate retarded the reaction kinetics.