Glucose addition improves the bio-remediation efficiency for crack repair

This study developed a novel method of glucose addition for the crack repair of concrete samples, which improved the bio-remediation efficiency. Various amounts of glucose were added to the medium at different sequence and the resulting absorbances were measured. Urea, calcium salt, and various amounts of glucose were mixed with an absorbance-fixed bacterial suspension and the resulting effect on calcium carbonate production was analyzed. Concrete specimens with irregular cracks were subjected to glucose addition for bio-remediation. Glucose addition decreased the pH, which inhibited the growth of bacteria. However, in a strong alkaline environment, this procedure was beneficial for crack repair. Informed by the bacterial growth and precipitation rates for calcium carbonate, addition of 10 g/L glucose was identified as the optimum concentration. After repair, the area recovery ratios of all samples exceeded 79%, while water penetration rates decreased significantly. The sonic time values of measurement points decreased and the strength of samples reached about 35% of the initial strength. Adding glucose to the medium during the repair improved the effect of the repair. This method can repair irregular cracks, accelerate the bio-remediation reaction, and reduce the repair time.