An experimental study on the usage of silica fume in bacterial concrete

Abstract

This paper shows the bacteria’s (Bacillus Megaterium) effect on the high-strength silica fume concrete made with M−sand. Various tests like split tensile strength, compressive strength test, RCPT, and ultrasonic pulse velocity test have been carried out. The concentration of bacteria was optimized and eight concrete mixes were designed. While making different concrete mixes the cement has been substituted with 10%, 15%, and 20% of silica fume by weight, with and without bacillus megaterium solution of 105 cfu/ml optimum concentration also used. Results indicated that the incorporation of bacillus megaterium in high-strength concrete enhances the split tensile strength, compressive strength, and ultrasonic pulse velocity and reduces the rapid chloride permeability and water absorption. The strength improvement and depletion in chloride permeability may have been due to the deposition of CaCO3 produced by bacteria in concrete pores. XRD confirms the engagement of bacillus megaterium in CaCO3 precipitation. The durability tests of specimens using H2SO4 and NaCl solutions will show the effectiveness of bacterial concrete using silica fume and M−Sand in Marine environments. The modelling of strength properties of different mixes is quantitatively correlated with Regression analysis.