Nanozeolite-modified cement for soft clay subgrade stabilization

Abstract Soft clay soils are commonly found in Egypt’s northern delta region and are known for their poor engineering properties, which limit their suitability as subgrade materials in pavement construction. This study investigates the stabilization of such soils using different binders: Ordinary Portland Cement (PC), El-Arish Modified Cement, and RoadCem (RC), a nanozeolite-based additive. El-Arish Modified Cement is a relatively new material recently introduced in Egypt, and its effectiveness in soil stabilization has not been extensively studied. Various mix designs were evaluated to determine the optimal stabilizer combination. The best performance was achieved using 16% PC (by soil dry weight) combined with 0.6% RC (by cement weight). Laboratory testing covered physical, mechanical, and microstructural properties, including strength, stiffness, and durability across different curing periods. The results demonstrated that while PC alone significantly improved the soil’s performance, the inclusion of RC further enhanced strength, stiffness, and durability. These findings suggest that nanozeolite-based additives like RC can be highly effective in improving soft clay soils for geotechnical applications, offering a promising solution for durable and sustainable subgrade stabilization. This addresses the limited local knowledge on the performance of El-Arish Modified Cement in clay soil stabilization.