Investigation of the microbial effect of wastewater on concrete performance

Abstract

Concrete subjected to wastewater environment deteriorates faster than its counterpart in an ordinary environment. The investigation also showed that the deterioration effect could also be counteracted using bacteria. This study investigated the deterioration and healing effects of bacteria isolated from wastewater on concrete properties like weight loss, compressive strength, modulus of elasticity and SEM analysis. The result at 28 days of curing showed that the greatest reduction in weight (4.2%) and compressive strength (16.69%) compared with control was observed in concrete inoculated with S. epidermidis; while the least decrease in weight (0.8%) and an increase in compressive strength (1.79%) was observed with the concrete cast with potable water and cured in nutrient broth medium. The healing effect of B. subtilis on the concrete was also considered and analyzed, the result showed that B. subtilis improved the strength of the concrete exposed to S. epidermidis. Scanning Electron Microscopy analysis showed that an increase in the pores within the concrete leads to a reduction in compressive strength.