Isolation of calcite precipitation bacteria to improve the strength of concrete

Tóm tắt

Concretes are the second most consumed material on earth. However, it is susceptible to micro crack formation and has pores in it. The repairing cracks in concrete require high cost and labor and traditional repair system are chemical based, expensive and lead to environmental and health hazards. In this study, the calcite precipitation bacteria were investigated. Bacterial strains were isolated from cement samples and were tested for urease activities, potential to form endospore and calcite precipitation. The results showed that four candidates were isolated with high urease activities and calcite precipitation. Among them, the bacterial isolate N1 could precipitate 0.5 g CaCO₃ per liter. By using 16S rDNA sequencing, this strain was identified as Bacillus thuringiensis. The ability of this strain to tolerate the extreme environment of cement, it could be used in remediating the cracks and fissures in various building or concrete structure.