Increasing structural resilience in high-strength concrete via microbial-based self-healing

Prolonged loading can lead to concrete cracking due to its weak tensile strength, impacting both durability and load-bearing capacity, especially when reinforcing bars corrode. This study investigates the efficacy of microbial-based self-healing in enhancing the performance of high-strength concrete, specifically targeting Bacillus Pasteurii and Bacillus Flexus. The findings indicate significant improvements in both micro- and macro-properties of high-strength bacterial concrete treated with these strains, surpassing control samples. Concrete infused with Bacillus Flexus exhibits a notable increase of 23.75% in compressive strength at 7 days and 12.36% at 28 days, with similar enhancements observed in Flexus-treated concrete. The presence of calcite precipitation, confirmed by X-ray diffraction and scanning electron microscopy, contributes to crack healing, achieving closure within 56 days. Microbial concrete from these strains demonstrates superior durability against water, acid, and salt exposure, suggesting the potential of microbial-based self-healing to fortify structural resilience and extend the lifespan of concrete infrastructure.