INFLUENCE OF BACTERIA ON STRENGTH AND SELF-HEALING CHARACTERISTICS OF FLY ASH CONCRETE

Traditional concrete is considered brittle, rigid and susceptible to cracks. Synthetic polymers used for the repair of cracks are susceptible to ultraviolet radiations, high cost and emanate toxic gases. This project presents the results of an experimental investigation carried out to evaluate the influence of Bacillus Megaterium bacteria on the compressive strength, split tensile strength, flexural strength and self-healing characteristics of concrete made without and with fly ash. Cement was replaced with four percentages (10, 20, 30 and 40) with fly ash by weight. A cell concentration of 105 cells/ml of bacteria was used in making the concrete mixes. Tests were performed at the age of 28 days. Test results indicated that the inclusion of Bacillus Megaterium in fly ash concrete enhanced the compressive, split tensile and flexural strength. This improvement in strength was due to deposition on the bacteria cell surfaces within the pores. The present work highlights the influence of bacteria on the properties of concrete made with supplementary cementing material such as like fly ash. Usage of bacteria like Bacillus Megaterium improves strength and durability of fly ash concrete through self-healing effect.