Response Surface Methodology for Optimizing Stabilization of Clay Soils Using Bacterial Calcium Carbonate Precipitation

The optimization of clay soils stabilization was investigated in this work using the application of response surface methodology. The main advantage of the response surface methodology is considered to be the robust structural reliability method to determine the best condition in the geotechnical system. In addition, it will also improve experimental design, strength performance, process efficiency, time management, and cost reduction. This work illustrates the optimum conditions of bacterial calcium carbonate precipitation (BCCP) application which significantly improve clay soils strength. There are four main parameters that need to be considered and evaluated, i.e., types of microorganisms, cementing materials, the molarity of cementing medium, and curing period. Each parameter in BCCP experiments was analyzed to evaluate the most impactful one. The results showed that the optimum condition occurred when using Sporosarcina pasteurii with 0.53 M of eggshell solution (ES) cementing materials and 4.11 days curing period. The unconfined compressive strength at the optimum conditions is 503.52 kPa.