基于火山石负载细菌的混凝土裂缝修复分析

To protect bacteria from strong alkali environment inside concrete, pelelith was used as the bacteria carrier to repair concrete cracks. Based on the study of the influencing factors of the activity of immobilized bacteria, the pelelith immobilized bacteria method and the conventional method for repairing concrete cracks were compared by unconfined compressive strength tests and ultrasonic tests. The results show that the immobilization effect is the best by the optimized immobilization method with the immobilization ratio of 1:4 and the immobilization time of 24 h. With the addition of nutrients, the decomposition concentration of urea of immobilized bacteria is significantly higher than that without added nutrients. The immobilized bacteria has high activity in the strong alkali environment with pH of 12, and the decomposition concentration of urea can reach 15.52 g/L for 48 h. In the same repair period, clear cracks can still be distinguished on the surface of concrete specimens repaired by the conventional method, while cracks are completely sealed by the method based on pelelith immobilized bacteria and the repaired concrete specimens have a high recovery rate of the compressive strength. The recovery rates of the compressive strength of specimens with the crack width of 1.5 and 2.0 mm are 19.68% and 15.51%, respectively.