Geotechnical Properties and Microstructure of a Diesel Contaminated Lateritic Soil Treated with Lime

Abstract

Studies involving oil-contaminated lateritic fine-grained soils are still scarce in literature, especially regarding treatments for improving soils mechanical properties. In this study, geotechnical properties and microstructure of a diesel-contaminated lateritic soil treated with lime are investigated and compared to tests conducted on lime-treated soil (2% to 8% lime) and diesel-contaminated soil (2 to16% diesel). The presence of diesel had no significant effect on soil plasticity but decreased soil strength. Lime stabilization applied to diesel-contaminated soils significantly improved soil properties after 6% of lime stabilizer. The diesel presence led to an inhibition of lime reaction due to reduction of cation exchange capacity and flocculation, which reflected in loss of its effectiveness in improving strength as compared to natural soil response. The water retention behavior and unsaturated hydraulic conductivity of soil were affected by diesel contamination, leading to curve shapes similar to clay materials. Adding 2% of lime to the contaminated soil, increase in the soil pores and changes in the shapes of water retention curve and k-functions were observed with similar behavior of a course-grained material. Overall, this study highlights how the presence of diesel and lime affects lateritic soil properties and microstructure.