Investigating the effect of lime on the swelling characteristics of forest roads

Swelling soils, characterized by fine particles, undergo volume changes due to water absorption and loss, posing challenges in road construction. Hence, enhancing the mechanical properties of such soils is crucial. Considering lime as a cost-effective, readily available, and easily applicable water-repellent material, this study investigates its influence on the swelling characteristics of high-plasticity clay soil (CH). Atterberg limit tests, including liquid limit (LL), plastic limit (PL), shrinkage limit (SL), plasticity index (PI), Proctor compaction, free swell, and swelling pressure tests were conducted based on standard procedures on control soil samples and soil samples mixed with different percentages of lime (3, 5, and 7%). Furthermore, mechanical test assessments were performed on specimens cured for 7, 14, and 28 days. The results indicated that the addition of lime decreased LL and PI while increasing PL and SL. Moreover, lime addition led to a reduction in the dry unit weight of the soil, an increase in the optimal moisture content, and a decrease in free swell and swelling pressure, with the most significant reduction observed in samples containing 5% lime. Additionally, the findings revealed that with increased curing time, free swell and swelling pressure reduced notably in samples mixed with 3% lime. In conclusion, the study demonstrates that lime can effectively improve the mechanical properties of swelling clay soils, especially crucial for road construction and soil classification purposes. Therefore, it can be concluded that lime is effective in reducing the swelling of forest soils.