Experimental study on performance of high strength microbial mortar

摘要

Traditional repair materials for masonry structures, such as the mixed mortar, cannot meet the general requirements of material strength and durability. Based on the biochemical actions of urea hydrolysis, certain types of urease producing microbes can significantly accelerate the precipitation of calcium carbonate in porous media, given that the environment is rich in calcium ions. The calcium carbonate crystals then bind the sand particles together to form the microbial mortar, which can be used to fill in the cracks of the deteriorated masonry structures. The paper studies the controlling factors of the strength of the microbial mortar, which controls the uniaxial compressive strength of the microbial mortar to be within 2-55 MPa. By X-ray diffraction, scanning electron microscopy and mercury intrusion tests, it is found that the microscopic pore structure of the microbial mortar is significantly different from that of the mixed mortar, which makes the former more suitable for the restoration of masonry structures.