All-solid-waste concrete with novel gelling particles solid-loaded with bacteria: mechanical properties and crack repair prediction

The self-healing technology of microbial concrete has attracted considerable attention. However, most current research focuses on Portland cement concrete, with relatively limited studies on self-healing in All Solid Waste Concrete (ASWC). In this study, a novel low-alkalinity gel particle (ASNC) was developed using Sulphate Aluminate Cement, silica fume, mineralizing solution, and nutrient solution, serving as a bacterial carrier. This carrier was utilized to immobilize Sporosarcina pasteurii, Denitrifying bacteria, and mixed bacteria, respectively, and then applied to ASWC. Microscopic characterization (XRD, SEM, EDS) was employed to verify the bacterial loading capacity of ASNC. A systematic evaluation was conducted on the crack self-healing effectiveness and mechanical properties of ASWC, and corresponding predictive models were established. The results demonstrate that ASWC with bacteria immobilized by ASNC exhibits outstanding performance in crack repair, compressive strength, and water absorption. Specifically, ASWC-BD with mixed bacteria immobilized can repair cracks with a width of 400 μm within 28 days, achieving a crack area repair rate of 98.33% and a compressive strength recovery rate of 81%. Furthermore, the predictive model provides a good assessment of the repair effectiveness. This study offers a novel direction for the application of microbial crack repair technology in ASWC.