Improvement of strength of locally available soils using microbial induced calcite precipitation

Abstract

Engineering properties of soils are improved by adopting various proven methods such as mechanical and chemical. Strength of locally available soil (Black cotton soil and red soil) was enhanced by application of Microbial Induced Calcite Precipitation (MICP) using species of Bacillus pasteurii. Microbial culture improves the unconfined compressive strength and shear strength of locally available soil. Microbial culture developed from Bacillus pasteurii, was used to stimulate and catalyze the process of calcite precipitation triggered by urea hydrolysis which includes reaction between urea and calcium chloride. This paper includes outcomes of effectiveness of MICP on locally available soil, on three parameters measure of the cementation reagent, measure of Bacillus pasteurii and duration of treatment process. The results elaborated that with the application of MICP, unconfined compressive strength of black cotton soil increased 1.6 to 2.3 times and red soil from 1.8 to 3 times. This gives optimum quantity of microbes and concentration of Cementation reagent as additive to improve strength of black cotton soil and red soil.