Asif Hossain Abir
The pursuit of net-zero infrastructure necessitates low-carbon concrete (LCC) formulations—such as slag blends, geopolymers, and limestone calcined clay cement (LC³)—which reduce embodied CO₂ by 20–40 % compared to ordinary portland cement (OPC). However, these materials often exhibit increased brittleness and crack susceptibility. Microbially induced calcium carbonate precipitation (MICCP) offers a promising solution by introducing an autonomous self-healing mechanism that enhances durability and service life. This review critically examines engineered MICCP strategies for LCC, highlighting: (i) microbial agents, including ureolytic and non-ureolytic strains, alongside emerging fungal and genetically modified alternatives; (ii) protective encapsulation materials like biochar, hydrogels, and silica gels, which preserve microbial viability for over six months; and (iii) hybrid delivery systems that enhance Ca²⁺ retention and improve healing efficiencies. Laboratory results demonstrate crack closure rates of 80–90 % and up to 95 % strength recovery, while field applications show lower performance, typically reaching 50–60 %. Incorporating MICCP into supplementary cementitious materials and geopolymer-based LCCs can reduce embodied carbon and enhance long-term durability. This review also addresses challenges, including bacterial viability in high-pH environments, encapsulation trade-offs, and regulatory barriers. Future research directions focus on optimizing microbial strains, encapsulation strategies, and field-scale deployment to unlock the full potential of MICCP in sustainable, climate-resilient infrastructure. • Microbial self-healing improves durability in low-carbon concrete (LCC) systems. • Bacillus-based bacteria and encapsulation enhance crack healing efficiency. • Genetic modifications increase bacterial resilience in high-pH environments. • MICCP in LCC contributes to CO₂ reduction and long-term infrastructure sustainability.