Study on Calcium Carbonate Deposition of Microorganism Bottom Grouting to Repair Concrete Cracks

Abstract

Microbially induced calcium carbonate deposition (MICP) restoration technology has good restoration effects and low environmental pollution compared with traditional restoration methods, and this technology has been applied in actual projects. However, grouting components such as bacterial solutions are easily lost in vertical cracks due to their low viscosity as well as their self-weight. In this paper, cracks were repaired using microbial mineralization by sealing the bottom of vertical cracks and pressure grouting. Controlled tests were designed based on three variables: crack width, presence or absence of media in the crack, and grouting method. The results show that the smaller the crack width, the easier it is to achieve a seal. The addition of media in the cracks can improve the repair efficiency. As the amount of grouting increases, the amount of calcium carbonate production in the cracks gradually increases, and the height and thickness of calcium carbonate deposition also gradually increases. The bottom closure pressure grouting method can not only reduce the amount of grouting fluid, but also shorten the test period. This method overcomes the difficulty that grouting poses as it should not be left in vertical cracks and plays an important role in reducing costs and shortening repair time.