Structural performance of self-healing concrete by Bacillus bacteria with addition of rice husk ash

Abstract

The spores of the bacillus bacteria release calcium carbonate (CaCo3) that fill-up the microcracks in the concrete, that is to say that this biological agent added in the concrete instead of deteriorating the material works as a self-healing agent, several investigations have studied the influence of this bacillus bacteria in the concrete mainly in the species baccilus genus showing its benefits for the concrete with respect to its increase of resistance in the concrete. On the other hand, a replacement for the cementitious material has also been studied, finding that rice husk ash (RHA) in a proportion of 10% not only works as a replacement but also contributes to an increase in the strength of the concrete. In the present work, the mechanical properties of fresh and hardened concrete were investigated with a 10% replacement of RHA and four concentrations of bacillus subtilus bacteria. The study presents the use of bacillus subtilus specie and its behaviour with the addition of rice husk ash. The results showed an increase in compressive strength of up to 25,83% compared to conventional concrete and 44.80% compared to concrete with RHA addition. This research aims to promote the use of bacteria in concrete, as they not only provide an increase in compressive strength but also enhance the concrete's service life by endowing it with self-healing capabilities.