Effect of Microbial Enzyme on Fly Ash and Assessment of Compressive Strength

Microbial-induced calcite precipitation is an emerging technique in the field of soil stabilization techniques. In the present ongoing study, the stabilization of fly ash is investigated through the MICP process. Sporosarcina pasteurii, a natural urease enzyme producing bacteria, has been considered because previous studies demonstrated that Sporosarcina pasteurii has a high urease enzyme producing capacity and can hydrolyze more than 90% of urea in a comparatively shorter time span. A urease enzyme is a type of enzyme that hydrolyzes urea and precipitates it as calcium carbonate (CaCO3). Two different cell concentrations of these microbes at OD600nm (0.8) along with a binding solution of urea and calcium chloride passed through a fly ash column of length and diameter (2:1) ratio. After microbial treatment, fly ash samples were subjected to an unconfined compressive strength (UCS) test. The test results show improvement in UCS value with treatment. The precipitation of calcium carbonate is the key material which binds with fly ash particles. The goal of this study is to look at fly ash as a building material and see if it can be used in the field.