Impact of Unhydrated Lime on the Geotechnical Properties of Clayey Soil

This study investigates the impact of quicklime (CaO) on improving the geotechnical properties of clayey soil. Quicklime was mixed with soil in varying proportions (2%, 5%, and 8% by dry weight) to assess its effects. The results showed that increasing lime content reduced specific gravity, while the optimum moisture content (OMC) and plasticity index increased. Additionally, the liquid limit, plastic limit, and plasticity index decreased, and there were improvements in compressive strength, friction angle, and unconfined compressive strength. Compression parameters such as the compression index (Cc), rebound index (Cr), volume change coefficient (mv), and compression modulus (av) decreased with increasing lime content. The most significant improvement was observed at 2% lime, with further increases to 5% and 8% resulting in less improvement. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses were conducted to explore the mineralogical and structural changes in the soil, demonstrating the chemical and physical interactions between lime and soil. This research provides valuable insights into the role of quicklime in modifying clayey soil properties, with implications for improving geotechnical performance in civil engineering applications, particularly in road and infrastructure projects. Doi: 10.28991/CEJ-2025-011-05-012 Full Text: PDF