Abstract: Porous ceramsite was used as microbial carrier. Based on the evaluation of compatibility between healing agents and concrete, and an optimal selection of ceramsite content, the self-healing of concrete cracks by bacteria was studied in view of mechanical performance and durability. Results indicate that beef extract and peptone in self-healing agents have a negative effect on concrete, while the effect of urea and calcium nitrate is insignificant. The optimum volume ratio of ceramsite is determined as 37.8%. The ceramsite immobilized with bacteria and organic nutrients is added to concrete. After 28 days curing for self-healing, the recovery ratio of compressive strength of the cracked concrete reaches about 63%, and its water absorption is significantly lower than that of the controlled sample. It can be observed that cracks are filled with calcite type calcium carbonate produced by microbial mineralization, and the maximum crack width can be healed is about 0.51 mm.
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2017, Vol. 31 
