Comparative Analysis of the Repair Effect of Three Methods of Microbial Induced Calcium Carbonate Precipitation on Recycled Aggregate Concrete Cracks
To obtain better technical solution of microbial induced calcium carbonate precipitation(MICP)to repair recycled aggregate concrete cracks,the optimum growth conditions of Bacillus megaterium were determined.Three methods of injection,agar immobilization and recycled aggregate immobilization with Bacillus megaterium were used.Comparative analyses of the maximum repair crack width,the area repair rate,reduction rate of permeability coefficient,deposition depth,micro morphology and composition of the deposited product were carried out under three methods.Theresults show that after repairing for 28 d,the maximum repair crack width uisng agar immobilization method is 0.66 mm,which is larger than 0.56 mm and 0.29 mm using the recycled aggregate immobilization method and the injection method,respectively.At the same time,the area repair rate and the reduction rate of permeability coefficient using agar immobilization method in the early stage are larger than that of the other two repair methods.Deposition depth using recycled aggregate immobilization method is the largest,and it is the smallest using agar immobilization method.The filling material from MICP to repair concrete cracks is proved to be calcite.MICP technology is effective to repair recycled aggregate concrete cracks,and appropriate immobilization method can significantly improve the MICP repair efficiency.
万方数据
维普
