Technoeconomic and Environmental Assessment of Self-Healing Bacterial Concrete as Sustainable Construction Material

The durability of conventional concrete remains a critical challenge for infrastructure exposed to moisture, cracking, and aggressive environmental conditions. Repetitive structural deterioration increases maintenance demands and shortens service life, highlighting the need for adaptive, self-repairing construction materials. This study investigates the performance of Bacillus subtilis -based self-healing bacterial concrete (SHBC) in M20, M25, and M30 grades, as a next-generation sustainable material, using a comprehensive techno–economic–environmental analysis (TEEA) for sustainable construction. Experimental results revealed that SHBC-M25 and SHBC-M30 exhibited superior mechanical and durability properties compared to conventional concrete. SHBC-M30 achieved the highest compressive, tensile, and flexural strengths (20–75 MPa), while SHBC-M25 demonstrated the most effective permeability reduction (up to 60%) and crack healing efficiency with strength recovery reaching up to 90% after 50 days of healing. Microstructural observations and X-ray fluorescence analyses confirmed the formation of calcium-based oxide compounds that play a key role in the healing mechanism and strength enhancement. Economic assessment using a life-cycle cost method indicates that, although the initial production cost of SHBC is higher, the total life-cycle cost of SHBC is 37%–47% lower than that of conventional concrete, leading to a reduced total cost of ownership. Further, environmental analysis through life-cycle analysis indicated a significant reduction in global warming potential and aquatic acidification impacts, reinforcing its green credentials. The TEEA score indicates that SHBC outperforms normal concrete, with SHBC-M30 achieving the highest sustainability score, followed by SHBC-M25. Thus, this study demonstrates the potential of SHBC as a sustainable concrete material for long-life, low-maintenance infrastructure projects.