Study on crack repair effect of microbial self-healing concrete and corrosion inhibition of steel bar

The application of microbial mineralization has attracted substantial attention in the field of steel bar corrosion inhibition. However, in environments abundant with harmful media, the composite film generated by this mineralization frequently fails to effectively prevent the penetration of such media. This research thoroughly investigates the influence of microbial repair agents on both the repair of cracks in self - healing concrete and the reduction of steel bar corrosion, which is of great significance for improving the durability and safety of concrete structures in various environments, especially those with high concentrations of harmful substances. The study discovers that concrete samples treated with microbial repair agents attain an outstanding surface crack repair rate of 97.1 %. Additionally, the ultrasonic wave velocity in these samples shows a significant increase, varying from 0.87 km/s to 3.34 km/s. The microbial repair agent efficiently forms a dense composite film on the steel bar surface, which consists of extracellular polymeric substances (EPS), mineralization products, and iron ions. This film not only mends cracks but also augments corrosion resistance. When combined with the crack - repairing function, the application of this agent results in a remarkable 53 % decrease in steel bar corrosion rates within the tested specimens, demonstrating its considerable value in enhancing the performance and longevity of concrete structures with embedded steel bars.