Abstract
The need to use self-healing concrete in inaccessible crack repairing positions has become an urgent issue. The concrete healing is a biological mechanism. Calcite crystals (CaCO3) such as calcite, vaterite, and aragonite are responsible for concrete crack healing. In this research, Bacillus marisflavi (from Ben Tre province), an alkaliphilic spore-forming strain that was isolated from 106 soil and concrete samples in Vietnam, exhibits urease activity which accelerates the formation of calcite crystal in the presence of urea. An assay of the bacterial addition into the concrete demonstrates a significant increase of the aragonite mineral up to 70.4%, a higher compressive activity (14.66 MPa after 14 d, and 29.32 MPa after 28 d) compared to the control (11.3 MPa after 14 d, and 15.95 MPa after 28 d). These findings show that the isolated Bacillus marisflavi strain has potential in concrete healing applications.
