Clayey soils are not favorable foundation for road pavement, due to their low bearing capacity and remarkable swelling potential because of water intrusion. Many previous studies demonstrated that the engineering quality of clayey soils can be improved significantly by physical and chemical stabilization techniques, thereby making clayey soils suitable for use in embankments. The present study examined the use of granulated blast furnace slag in powder-form, commercial lime and seawater to improve the engineering properties of a low-plastic clay soil. Clay soil samples were reconstituted by adding various percentages (by weight) of GGBFS, lime, and seawater at optimum water contents, based on compaction tests results. The specimens were cured for 1, 7, and 28 days. Unconfined compression and California bearing ratio (CBR) tests were conducted. The results indicated that the unconfined compression strength of the clay samples (stabilized with 5 % lime, 3.33 % GGBFS and cured for 28 days) was more than eight times the initial strength of the untreated samples, reaching 2500 kPa with seawater. Soaked CBR values also increased to more than ten times the initial value.