A Novel Technique on Improving the Strength of Concrete Using Microorganisms

The main objective of this study is to isolate a novel bacteria from an unfamiliar source and to test its calcium precipitating ability to fill the pore present in the structure by filling the voids in the concrete matrix and to predict the suitability of the bacteria for better use in cementitious mixture to improvise the mechanical properties of concrete. The selected bacteria should have the significance of producing high urease for the precipitation of calcium carbonate. For this present study, bacterial strains were isolated from sludge and sewage samples of waste water treatment plant, Nesapakkam, Chennai. The colony which has high urease activity among obtained group of colonies was identified as Enterobacter ludwigii bacteria and the results were compared with the well-known traditional bacteria used in self-healing concrete, Bacillus subtilisin terms of performance and viability. The experimental work on mortar with bacteria inoculated in them revealed that the microbial induced mortar showed an enormous increment in the strength then conventional. Characterization studies are performed to confirm the presence of calcium carbonate precipitate through compressive strength test and ultrasonic pulse velocity test and the visualization of calcium carbonate were done by using a Scanning Electron Microscope.