Microstructural Studies on Enzyme-Modified Lateritic Subgrade

Ground improvement using sustainable and environmentally friendly agents have been the focus of research in the recent years. Biological stabilization is one of the emerging techniques in this field which aims at enhancing the engineering properties of soil through enzyme treatment. This technique eliminates the use of conventional resources and improves the economic aspects of construction projects. This paper explores the potential of bio-enzymatic stabilization in attaining the permanency in the strength of the lateritic pavement subgrade which, in turn can potentially contribute to the development of pavement design guidelines. The economic viability and longevity of bio-modification through different dosages as well as curing periods are studied and the results are compared. In this study, correlation is established between CBR and unconfined compressive strength of bio-modified soil with reference to the soil properties. The bio-enzyme is found to increase the unconfined compressive strength and resilient modulus of lateritic soil. At higher curing periods, the rutting life of enzyme treated lateritic pavement is found to increase while the damage ratio decreases. X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) studies have been performed in the present work to understand the microstructural behavior of enzyme treated soil. Cost analysis is also carried out in the present work to understand the economic feasibility of enzymatic stabilization. The cost analysis studies indicate a reduction in the rutting of pavement, which contributes to a longer service life of enzyme treated lateritic pavement.