Feasibility Study of Petrochemical Waste and Cement Usage for Saline Road Subgrade Stabilisation

The widespread distributions of saline soils in Iran cause a range of problems for road construction projects due to insufficient shear strength, salt solubility potential and swelling. This paper conducts experimental tests using different cement contents and a sort of petrochemical waste with two curing methods to stabilise saline soil samples. Strength, compressibility and chemical tests were conducted, X-ray diffraction analyses were performed, and scanning electron microscope pictures were prepared for basic materials and stabilised saline soil samples in this paper. The results indicate that both petrochemical soda ash waste and cement enhance the shear strength of saline soil, especially after 28 days of curing. However, the combination is more appropriate from the swelling and salt solubility potential viewpoint. The optimum combination of 2% cement and 5% of petrochemical soda ash waste, cured by method 2 for 28 days, results in the most significant shear strength enhancement (127%). Furthermore, a swelling quantity of the optimum combination is reasonably restricted. X-ray diffraction test results and scanning electron microscope pictures demonstrated that despite the presence of ettringite agents, the formation quantity of these minerals is negligible. The salt is well stabilised, and its solubility potential dramatically decreases.