Experimental and analytical study on the flexural rigidity of microbial self-healing concrete based on recycled coarse aggregate (RCA)

Abstract In this paper, a microbial self-healing concrete was prepared by using recycled coarse aggregate (RCA) as a bacterial carrier. Based on the virtual crack model, the cohesive stress of the crack tip was theoretically analyzed and calculated to determine the nature of its flexural rigidity healing. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and crack width measuring showed that the microbial induced precipitates in the crack were CaCO3 and that the healed crack width could reach 0.25 mm after 28 days of healing. After 28 days and 56 days of healing, the flexural rigidity healing ratio of the specimen (BRC) using RCA as the bacterial carrier could reach 12.25% and 53.02%, respectively. Moreover, the flexural rigidity was predicted based on the crack characteristic parameters after healing, and the difference between the experimental value and the predicted value was found to be small.