Improvement of the geotechnical properties of a clay–sand mixture treated with lime

The use of lime or sand as stabilizers gave satisfactory results in improving the physical and mechanical properties of the expansive soils. The main aim of this research is to study the effect of adding dune sand, lime and their combination on the behavior of an expansive clay soil. Dune sand and lime were added to the high plasticity clay soil (CH) within the percentage of 0–30% and 0–9%, respectively. According to tests results, it can be noted that both of dune sand and lime can improve the geotechnical properties of the expansive soil by reducing their plasticity and increasing their unconfined compressive strength. The combination of lime and dune sand can appreciably improve the studied properties of the clay soil compared to the use of dune sand or lime alone, especially with the optimal combination which consists of 20% dune sand and 3% lime. Denser soil structure with more flocculated soil particles and additional cementation products are observed when adding dune sand to the lime-treated soil compared to using lime alone.