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ABSTRACT
Concrete is the most critical element applied in public infrastructure/buildings and is often difficult to service, yet requires lengthy service periods. Recent research has shown that specific species of bacteria can actually be useful as a tool to repair cracks in already existing concrete structures. This new concrete, that is equipped to repair itself, presents a potentially enormous lengthening in service-life of public infrastructure/buildings and also considerably reduces the maintenance costs. In addition, concrete by its nature is very prone to deformations that expose its reinforcements, corroding them. Self-healing concrete offers a solution to prevent this. A novel eco friendly self healing technique called Biocalcification is one such approach on which studies were carried out to investigate the crack healing mechanism in enhancing the strength and durability of concrete. Microbiologically induced calcite precipitation (MICP), a highly impermeable calcite layer formed over the surface of an already existing concrete layer, due to microbial activities of the bacteria (Bacillus subtilis JC3) seals the cracks in the concrete structure and also has excellent resistance to corrosion.
KEYWORDS: Biominerilization, Calcium Carbonate, Bacillus subtilus, Self-healing concrete, bacterial concrete
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I. INTRODUCTION
Concrete is a vital building material that is an absolutely essential component of public infrastructure and most buildings. It is most effective when reinforced by steel rebar, mainly because its tensile strength without reinforcement is considerably low relative to its compressive strength. It is also a very brittle material with low tolerance for strain, so it is commonly expected to crack with time. These cracks, while not compromising structural integrity immediately, do expose the steel reinforcement to the elements, leading to corrosion which heightens maintenance costs and compromises structural integrity over long periods of time. That being said, concrete is a high maintenance material. It cracks and suffers serious wear and tear over the decades of its expected term of service. It is not flexible and cannot handle significant amounts of strain. Standard concrete will bear up to approximately 0.1% strain before giving out [1]. Self-healing concrete in general seeks to rectify these flaws in order to extend the service life of any given concrete structure. There is a material in the realm of self-healing concrete in development, now, that can solve many...