Investigation of the effect of sodium chloride salt on the geotechnical properties of loess soil

Soil is one of the essential building materials, and the primary support of structures has long been a human interest. However, due to weakness in shear strength and lack of resistance to tensile forces, researchers have consistently sought to increase its bearing capacity, strength, and improve its properties and various methods including mechanical modification such as compaction, chemical modification such as treatment with lime, cement or salt. The purpose of this study is investigation of the effect of sodium chloride salt on the geotechnical properties of loess soil. Loess soil was sampled from a Golestan province region and transferred to the Soil Mechanics Laboratory of the Shams University of Gonbad-e-Kavos. Sodium chloride salt was added to soil sample with content of 3, 6 and 9% by weight of soil. Soil samples were prepared in normal condition (without additives) and with different content of sodium chloride for geotechnical properties tests. The results show that the addition of sodium chloride salt reduces the plastic and liquid limits in the Atterberg limits test, increases the dry weight unit weight and decreases the optimum moisture in the compaction test, increases the strength in the unconfined compressive strength test and increases the cohesive and friction angle in the direct shear test.