Bacterial concrete - A remedy for micro cracks

Abstract

Carbonate-producing bacteria have attracted lots of interest as a promising, natural, environmental friendly novel technique to 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 optimum dosage of bacterial solution and its effect on the durability of concrete has not been comprehensively investigated. Therefore, it is decided to carry out an investigation of determining optimum dosages of bacterial solution required for concrete by forming various concrete cube samples having variations of bacterial solution viz. 15 ml, 30 ml, 45 ml, 60 ml and 75 ml. Further these various samples are tested under various laboratory methods viz. slump cone test, compressive strength testing machine, ultrasonic pulse velocity test, plate count cells and scanning electron microscopes thereby an optimum dosage required is computed. Bacterial concrete is found to be superior as compare to that of conventional concrete in all the aspects of durability. Among the different specimen incorporated it shows that bacterial concrete containing 45ml solution is the optimum dosage required, after which the strength found to be stable or decreased.