Enhancing engineering properties of cement mortars through microbial self-healing and community analysis

This study explores the enhancement of crack healing in cement mortars through microbial-induced carbonate precipitation (MICP), utilizing a facultative anaerobic denitrifying bacterial strain encapsulated within sodium alginate and bentonite. Evaluations demonstrated that microbial specimens achieved complete crack closure within 14 days, displaying a 71.7 % increase in compressive strength by day 14, and showed marked improvements in water absorption and porosity compared to controls. The sealf-healing mechanism in microbial specimens was confirmed with microstructural analyses performed with XPS, XRD and FTIR analyses. The dynamics of microbial communities within the concrete matrix revealed significant shifts in microbial populations and functionalities over time, predominantly enriched with Proteobacteria and Firmicutes. These communities supported biogenic precipitation under varied oxygen conditions, enhancing healing mechanisms in both oxygen-rich and deficient environments. This microbial self-healing approach not only promises significant cost savings but also reduces the environmental footprint compared to conventional repair methods, offering sustainable advances for the durability of civil infrastructures.