Evaluating the Effectiveness of Soil-Native Bacteria in Precipitating Calcite to Stabilize Expansive Soils

The use of chemical additives to stabilize expansive soils is a common practice. However, the environmental concerns associated with the greenhouse gas generation during the production of these chemicals have launched engineers in search of sustainable stabilization alternatives. Microbial induced calcite precipitation (MICP) is a bio-cementation technique that could be a potential solution to this problem. Typically, MICP is achieved via bio-augmentation; however, bio-stimulation was argued to be a more realistic alternative due to its field implementation potential. Hence, in this research study, two expansive soils with varying plasticity characteristics were examined to understand the potential of MICP in treating expansive soils. These two soils were subjected to MICP treatments using enrichment and cementation solutions. The treatment effectiveness was studied via response measures such as Atterberg limits, unconfined compressive strengths, one-dimensional swell test, and calcium carbonate precipitation. The results indicate that MICP has potential in stabilizing expansive soils and further research is warranted to explore this idea