Effect of saline soil on soil–cement strength: a short-term analysis

Saltwater intrusion is increasingly raising salinity levels in groundwater, posing significant challenges for construction practices in coastal and saline areas. Although soil–cement stabilisation is widely used in civil engineering projects, particularly in areas prone to salinity, comprehensive insights into how salinity affects soil–cement strength and durability remain limited. This study investigates the influence of varying saline soil conditions, which were tap water, saline water, and highly saline water, on the compressive strength of soil–cement mixtures with 10% and 30% by weight cement content and cured for 7, 28, and 90 days. The results show that soil cement with highly saline water significantly enhances early-age strength, achieving the highest unconfined compressive strength of 3571.3 kPa at 90 days. The strength improvement is attributed to accelerated cement hydration induced by chloride ions, which promotes calcium silicate hydrate (C–S–H) formation and densifies the microstructure. Increased salinity and cement content reduce porosity and strengthen cementitious bonds. These findings provide novel insight into the mechanistic role of salinity in soil–cement performance and offer practical guidance for effective soil stabilisation in saline and coastal environments.