Investigation of the Strength Properties of Clayey Soils Stabilized with Rice Husk Ash Lime and Cement

This study investigates the improvement of a highly plastic clay soil using lime, cement, and rice husk ash, as well as the effects of these additives on the soil’s strength properties. In the experimental program, a clay sample obtained from Asilbeyli Village in Kırklareli Province was used. After determining the engineering properties of the natural soil, lime, cement, and rice husk ash were added to the soil in different proportions, both individually and in various combinations. Subsequently, unconfined compressive strength (UCS) and California Bearing Ratio (CBR) test specimens were prepared. The specimens were cured for 1, 7, 28, and 90 days, after which UCS and CBR tests were conducted. The results indicated that lime and cement significantly improved the soil strength, while rice husk ash, owing to its pozzolanic properties, further enhanced the effectiveness of these additives. In particular, for the lime–rice husk ash combination, the unconfined compressive strength increased approximately sevenfold, and the CBR value increased fivefold after 90 days of curing. The use of rice husk ash provides a sustainable approach to soil improvement from both economic and environmental perspectives. Therefore, the combination of rice husk ash with lime and cement emerges as an effective and eco-friendly alternative for enhancing the bearing capacity of weak soils.