Use of Bio-Active Bacillus subtilis bacteria to form self-healing concrete

Abstract

Self-healing concrete or bio-concrete is considered as one kind of “living” smart materials. Recently, bio-concrete has become more attractive to researchers around the world because of its promising future in improving concrete durability. In this study, we investigate the role of Bacillus subtilis in healing cracked cement. Bacillus subtilis 10⁹cfu/g and 10¹¹cfu/g, respectively, was tested in the different scale sample: normal condition in Petri plate, binding in cement hydrate product and dispersing in cement mortar 40x40x160mm. From the result of XRD analysis and microscopy (OP, SEM), calcite precipitates were found after curing time of 7, 14, and 28 days. In the presence of this calcite deposit, both results of compressive and flexural properties of cement mortar increased up to 30%. The self-healing effect was tested with a priori crack 0.5mm in large of a prismatic sample during 14 days of curing time. Specific discussion on the obtained results permit us to extend this study for concrete sample.