Abstract：Microbially induced carbonate precipitation (MICP) can provide self-healing of cracks in concrete to prolong the service life of concrete structures. However, the survival rate of the bacteria incorporated into the concrete directly affects the self-healing capability. This study used concrete with a high porosity expanded perlite as the bacteria carrier which possessed excellent crack self-diagnosis and self-healing properties. The study analyzed the effects of different types of mineralized bacteria on the concrete crack self-healing and the microstructures of the crystals inside the concrete cracks. The results show that a pure culture of Bacillus cohnii and a microbial consortia of aerobic, facultative anaerobic and anaerobic bacteria both exhibited excellent healing capacities. The crack healing rates of the concrete after curing for 28 days were 73.3% for Bacillus cohnii, 83.3% for the aerobic, 63.3% for the facultative anaerobic and 41.5% for the anaerobic bacteria. The microstructure analyses show that the crystals in the concrete cracks formed by different types of mineralized bacteria were various forms of calcium carbonate crystals. The results of the present study will be useful for further studies of the crack-healing properties of concrete based on MICP.
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2019, Vol. 59 
