Bacterial concrete: the future of self-healing and sustainable infrastructure

This study investigates the durability enhancement of bacterial concrete incorporating microbial strains (Bacillus Licheniformis, Bacillus Flexus, Pseudomonas stutzeri, Escherichia coli, and Bacillus subtilis) through microbial-induced calcium carbonate precipitation (MICP). Various durability tests, including water absorption, RCPT, sulphate resistance, hydrochloric acid strength loss, sorptivity, and energy-dispersive X-ray analysis (EDAX), were conducted to evaluate the effectiveness of bacterial concrete. Bacterial concrete significantly reduces water absorption and chloride ion penetration, with Bacillus subtilis (M16) and Bacillus Flexus (M7) demonstrating the highest impermeability. Sulphate resistance analysis confirmed reduced weight loss before and after healing, highlighting microbial self-healing capabilities. Hydrochloric acid strength loss and sorptivity tests further validated improved acid resistance and reduced capillary absorption. EDAX analysis confirmed the formation of calcium carbonate, contributing to matrix densification and enhanced durability. Overall, microbial concrete exhibited superior resistance to environmental degradation, with Bacillus subtilis, Bacillus Flexus, and Bacillus Licheniformis at higher concentrations (10⁶ cells/ml) providing the most significant improvements. Bacterial concrete showed increased workability and notable compressive, flexural, and split tensile strengths with Bacillus subtilis and Bacillus licheniformis at 10⁶ cells/mL, Bacterial concrete provide the best self-healing and strength recovery capability; SEM and XRD data revealed higher density and effective crack healing. Bacterial concrete is a sustainable material since it provides long-term durability by means of inherent self-healing systems.