Strength and durability improvement of cement-stabilized Al-Qatif soil by the addition of sand

High plastic soils tend to show poor engineering performance especially low compressive strength, and soil-cement stabilization is one of the most popular practices to enhance their performance. However, all clayey soil-cement stabilization may not yield the expected outcome. This research was carried out to determine if the compressive strength and durability improve by adding natural sand while stabilizing Al-Qatif green soil with cement. To achieve this objective, characterization tests were performed to determine the geotechnical properties of the investigated soil. Cement was added to soil samples at various percentages (0%, 2.5%, 5%, 7.5%, and 10% of the dry soil weight) to enhance the soil’s structural properties. The soil sample stabilized with 10% cement and cured for 28 days gained the highest strength of 1.73 MPa, which is below the required 2 MPa. However, when the soil sample was stabilized with 5% cement with the addition of 50% sand and cured for 28 days, it gained strength of 2.89 MPa, which passed the strength criteria. It was observed that the strength gain increased proportionately with the increase of sand content, with 50% sand content yielding the highest strength gain of more than 100% at each tested cement content. The durability of the stabilized soil samples improved, too, as reflected by the significant reduction in weight loss with the increase in cement sand content.