Characterization of ureolytic based bio concrete

Abstract

One of the oldest and most popular building materials in the world is concrete., mostly because it is inexpensive, readily available, has a long lifespan, and can withstand harsh weather conditions. But as concrete is brittle tends to fail in cracks more. The consequence of micro-cracks in concrete is many such as corrosion, faster degradation of the structure, reduced load-carrying capacity, etc. As it is impossible to avoid these cracks due to their behavior, many new techniques have been explored to repair them. But with a sustainability perspective, it is important to proceed such that it can benefit the environment. Therefore, the aim of the present work focuses on sustainability solutions for crack repair and strength enhancement. One such mechanism is Calcium carbonate precipitation from the bacteria to fill the cracks. CaCO3 has been observed to blend with concrete easily and enhance its properties. Among different pathways available, the use of ureolytic bacteria such as the Bacillus family to obtain CaCO3 by degrading urea is more effective and economical. The current study used culturing of a new type of Bacillus pseudofirmus and Bacillus cohnii bacteria to investigate the stress behaviour and resilience of concrete. A large number of samples were cast to investigate various strength properties such as compressive, flexural, split tensile strength, water absorption, and SEM analysis. According to the results of the tests, there was a 36.36% growth in compressive stress for 106 cell concentrations after 56 days. Similarly, there was a noticeable growth in split tensile and flexural stress. SEM images, finally, confirmed the occurrence of CaCO3 in the mix. The outcome of this study can assist researchers and the construction industry to look into the different possibilities to enhance the properties of concrete.