ABSTRACT
Microbial carbonate precipitation as a soil improvement technique has the prospect of becoming a substitute to traditional soil improvement in terms of performance and environmental sustainability. This study examines the carbonate biomineralization process mediated by the urease active strain of Sporosarcina pasteurii (ATCC® 11859TM) in tropical residual soil. The effects of bacteria concentrations, curing conditions and treatment durations were the major parameters evaluated. Bacteria concentrations of 1 × 105 cfu/ml and 1 × 106 cfu/ml and 0.5 M concentration of cementation reagents were used for the study. The soil specimens were cured at atmospheric temperature and 40°C and treated for 24, 36, 48 and 60 hours durations. Shear strength and calcite precipitated at each treatment were evaluated. The results indicated a general increase in strength with increase in curing temperature; an indication of temperature influence in bacterial activity. Meanwhile, higher concentration of bacteria of 1 × 106 cfu/ml resulted in higher strength and calcite content.
