Application of escherichia coli. as a smart bio-agent to make sustainable future generation concrete

Concrete is an artificial manmade building material which is obtained by carefully permitting proportioned mixture of cement, sand, stone/brick chips and water. Appropriate adjustments of these ingredients can lead concrete with vast ranges of properties. Although concrete can tolerate compressive forces like natural stone, it is prone to cracking due to tensile forces. Thus, crack formation is a widespread phenomenon in concrete, which allows different kinds of foreign substances and water into the concrete structures and reduces the life span of the infrastructures. The possibility of cracking can increase with time due to the variation in humidity and temperature. Maintaining or repairing concrete-based structures can be very costly. Use of self-healing concrete using microbial agent is demonstrated very beneficially in the present scenario for the construction of durable structures. It is proved to be advantageous for improving the properties of concrete and also for reducing the maintenance costs. In this study 100×100×100 mm cubical concrete specimens were prepared with or without using Escherichia coli bacteria and periodically subjected to compressive and split tensile strength test. About 10% and 23% increment in compressive and split tensile strengths were respectively observed after 28 days of curing period due to addition of E. coli bacteria in concrete. Later on, UPV and SEM analysis were also performed to evaluate material properties. SEM analysis also confirmed the crystalline structures within the powdered mortar sample. Hence, the use of E. coli bacteria in concrete is arranged towards increasing sustainability and decreasing the all-out cost-of-ownership for structures.