扩散法用于微生物矿化修复混凝土竖向裂缝的试验研究

Experimental Study on Repairing Vertical Cracks of Concrete by Microbial Mineralization with Diffusion Method

为了研究微生物诱导碳酸钙沉淀(Microbially induced carbonate precipitation,MICP)技术对混凝土裂缝的修复效果,分别采用扩散法、注射法对竖向裂缝宽度为0.1 mm、0.2 mm和0.4 mm的混凝土试件进行了MICP修复,并从微观(生成物成分及形貌)和宏观(耐久性能和力学性能)两个角度对裂缝修复效果进行了评价和对比分析。试验结果表明:与注射法相比,扩散法中的海绵条不仅可以存储胶凝溶液,还能为碳酸钙沉积提供附着点,这使得经扩散法修复后的三种裂缝宽度的混凝土试件的防水性能和抗氯盐侵蚀性能更好,这两种性能的平均提升系数分别达到了79.7%、60.9%,但劈裂抗拉强度的提升不明显。上述研究结果表明,采用扩散法修复混凝土构件中非受力状态下的竖向裂缝是有效的,可供实际工程应用参考。

In order to investigate the effectiveness of microbially induced carbonate precipitation(MICP)in repairing concrete cracks,concrete specimens with vertical crack width of 0.1 mm,0.2 mm and 0.4 mm were repaired by MICP with diffusion method and injection method respectively.The effectiveness of repairing cracks was evaluated from the microscopic(composition and morphology of products)and macroscopic(durability and mechanical properties)levels.The results show that the sponge strip used in diffusion method not only store cementation solution,but also provide attachment point for calcium carbonate deposition.The waterproof performance and chloride aggressive resistance of concrete specimens with three crack widths repaired by diffusion method were better than those by injection method,and the average improvement coefficients of these two properties reach 79.7%and 60.9%,respectively.However,the increase of splitting tensile strength was not obvious.The above research results show that the diffusion method was effective to repair the vertical cracks in the unstressed state of the concrete members,which can provide reference for practical engineering.