Self-healing concrete using bacillus subtilis natto immobilized in lightweight aggregate

Abstract

Concrete is probably the most important and commonly used construction material. However, concrete still faces quality degradation problems caused by cracks. Concrete is probably the most important and commonly used construction material. However, concrete still faces quality degradation problems caused by cracks. In leading to sustainable development, management methods will be better than repairing the cracks in concrete. With high ability to be cultured and CaCO3 precipitation, the potential to use Bacillus subtilis natto in full-scale application is promising. Although the bacteria were transformed into spores before mixing to concrete, their survival is still minimal. In this study, the high survival rate of bacteria immobilized in lightweight aggregate reflected through later-age-crack strength restoration rate contributes essential information for maintaining self-healing for a long time. Experiements also clarifies the bio-mineralization of Bacillus subtilis natto with the effects of nutrient-low medium to find a suitable way to protect and maintain the self-healing abilities in a long time. The effect of cracking age on the self-healing capacity associated with the compressive strength improvement was clarified.