Effect of pH on bacterial concrete

Abstract

Carbonate-producing bacteria have attracted lots of interest as a promising, natural, environmental friendly and novel technique for improvement of concrete characteristics. Considerable research has been conducted on utilizing microbial-induced carbonate precipitation to mitigate several concrete problems such as crack repair, reduction and modification of porosity and permeability. Furthermore, bacterial carbonate precipitation (bio deposition) has shown positive influences on compressive strength improvement of concrete. In the meantime, it seems that the study related to the Sustainability of bacteria at various pH levels and its effect on the durability of concrete has not been comprehensively investigated. Therefore, it is decided to carry out an investigation of determining the optimum pH value required for cement mortar by forming various cement mortar cube samples having different pH value wiz. 6.25, 6.5, 6.75, 7.0, 7.25, 7.5, 7.75, 8.0, 8.25, 8.5, 8.75. Further these various samples were tested under various laboratory methods viz. Compressive strength testing machine, Moisture content, Acid test on bacterial residue, Rebound hammer test, Colony forming unit/plate test and Scanning electron microscopes thereby an optimum pH value required is computed. Bacterial concrete is found to be superior as compare to that of conventional concrete in all the aspects of durability.