Compressive response of bio-strengthened engineered cementitious composites (ECC) with self-healing characteristics

• Self-healing of cementitious composites reinforced with 5 microbial species was assessed through compression. • The 5 microbial species were: B. subtilis (AG174 and P479), B. megaterium , B. stearothermophilus , and S. globispora . • Samples with S. globispora at a 4 × 10 5 cfu/ml of cell concentration achieved an average compressive strength of 92.7 MPa. • B. subtilis at a 2 × 10 8 cfu/ml of cell concentration had a superior healing of cracks with a maximum width up to 4.9 mm. • S. globispora at a 2 × 10 8 cfu/ml of cell concentration had post-healing compressive strength recovery of up to 134.1 %. This research aims to develop fiber-reinforced engineered cementitious composites (ECC) with self-healing characteristics for mitigating cracks and enhancing durability. Bio-enhanced ECC was developed by incorporating various bacterial strains. The mechanical and healing responses of the composites were investigated. Five bacterial strains, Bacillus subtilis ( B. subtilis AG174 and PY79) , Bacillus megaterium , Bacillus stearothermophilus , and Sporosarcina globispora (S. globispora), were evaluated. The impact of the bacterial strains on the compressive response, crack-sealing, and strength recovery was assessed. Additionally, the effect of varying composition of calcium lactate (nutrient and calcite precipitation precursor) on the compressive response of ECC was evaluated. Also, the impact of replacing fly ash with recycled glass pozzolan was also investigated. The bio-enhanced ECC exhibited high compressive strength and exceptional crack-healing/sealing abilities. An average compressive strength of up to 13,450 psi (92.7 MPa) was observed in samples with S. globispora at a cell concentration of 4 × 10 5 cfu/ml. Superior crack sealing of up to 4.9 mm was seen in samples reinforced with B. subtilis at a concentration of 2 × 10 8 cfu/ml. Post-healing compressive strength recovery of up to 134.1 % was observed in samples with S. globispora at a concentration of 2 × 10 8 cfu/ml. The findings indicated that replacing fly ash with recycled glass pozzolan led to an increase in compressive strength and a decrease in crack healing. The results showed that increasing the quantity of calcium lactate promotes crack healing but leads to a reduction in compressive strength.