Experimental Research into the Repair of High Temperature Damage to Cement Mortar Samples Using Microbial Mineralization Technology

Experiments such as microbial activation culture, subculture selection, and fire damage repair of cement mortar specimens were conducted to investigate the repairing effect of Sporosarcina pasteurii as a repair agent for fire-damaged cracks in cement mortar specimens. In addition, multi-scale parameters such as compressive strength and chloride ion migration coefficient of cement mortar specimens before and after restoration were compared. The effect of microbial mineralization technology on the repair of fire-damaged cracks in cement mortar specimens was investigated, and the microstructure and mineral composition of the products were analyzed. The results showed that the strong alkaline environment in the cracks of the cement mortar specimens after a high temperature of 500 °C inhibited the activity of bacteria and weakened the mineralization effect; the compressive strength of the repaired cement mortar specimens was 22.8% higher than that of the unrepaired fire-damaged specimens; the compressive strength of the repaired cement mortar reached 78.2% of the strength of the original cement mortar specimen without high temperature; after restoration, the chloride ion penetration resistance of the cement mortar specimens decreased by about 16.9% compared with that before restoration.