Use of Bioslurry for Stabilization of Florida Soils

In recent years, microbially and enzyme-induced calcite precipitation (MICP and EICP) have gained traction as ecologically friendly methods for stabilizing soils. More recently, using the concepts associated with MICP and EICP, "bioslurry" was developed. Bioslurry is very similar to traditional MICP, but calcium and urea are added to the initial bacterial solution. In this study, several Florida soils were treated with bioslurry using a combination of techniques, ratios of bioslurry to cementation solution, and solution concentrations. Specifically, two soils were examined—beach sand and soil with high organic content. Beach sand specimens were treated via a surface percolation technique and subject to erosion testing using a pocket erodometer. Soils with high organic content were treated using a hand mixing technique and were tested for unconfined compressive strength. In addition, preliminary X-ray diffraction analysis was conducted on treated specimens to characterize crystallization. Regardless of soil-type or test-type, results appeared to indicate that optimization was achieved when approximately 25% of the specimens' pore volumes were filled with bioslurry and 75% of their pore volumes were filled with cementation solution (i.e., calcium plus urea) and that at this approximate optimization point, soil properties were improved.