Bacterial Concrete-A Concrete for the Future

Abstract

This paper describes the microbial remediation of cracks in cement mortar specimens that substantially increased the compressive strength, stiffness and modulus of rupture. Additionally, the durability characteristics of the specimens improved also. Test results have clearly demonstrated that microbiologically induced calcite precipitation is effective in remediation of cracks. Scanning electron microscope (SEM) examination was found to be an effective method for characterizing the process of microbial mineral precipitation in cement mortar. The unique imaging and microanalysis capabilities of SEM identified the presence of calcite precipitation inside cracks, bacterial impressions and a new calcite layer on the surface of cement mortar. The calcite layer improves the impermeability of the specimen, thus increasing its resistance to alkaline, sulfate and freeze-thaw attack.