Development and characterisation of bacteria as a potential application in enduring the mechanical and durability characteristic of cement composite

Abstract

ABSTRACT The current research focuses on the biomineralization in cement composite by Bacillus sphaericus and Escherichia coli bacteria. The Escherichia coli (E. coli) was isolated from the soil beneath the leaked sewage pipe. Harvesting the E. coli bacteria required isolation, growth, cultivation and characterisation. Furthermore, the potential of micro-organisms was checked on the mechanical properties of the cement composite and durability properties such as water absorption, rapid chloride permeability test (RCPT), and ultrasonic pulse velocity on 7- and 28-day curing period respectively. The bacterial cell concentration of 106, 107 and 108 cells/ml were chosen and mixed during concrete manufacturing. The results revealed that the mechanical properties of the concrete prepared from micro-cultures exhibiting improvements over strength. CNT-EC8 was showing 18.73% (39.3 N/mm2) and 13.08% higher compressive and split tensile strength during 28 days respectively. Despite this, they also show 33.07% and 45.14% lesser charge passage rate in RCPT test respectively. The bacterium was shown to be capable of producing calcite precipitation, filling the micro pores and improving the cement composite’s durability. As a result, using microbially generated crystal in concrete can be a useful strategy for lowering permeability and developing long-lasting concrete.