Use of Saline Water in Compaction of Engineered Fills

Abstract

Many arid regions in the world have limited fresh water supplies but are near oceans or inland saline lakes. In these locations, it can be expensive and difficult to use fresh water for moisture conditioning during soil compaction of grading projects. However, local high salinity (ocean water or water from inland saline lakes or seas) water is often abundant and much less expensive than fresh water. Due to limited background research regarding the behavior of soils compacted using high salinity water, engineers generally prohibit its use for water conditioning required during compaction. The limited amount of literature on the subject suggests that using high salinity water instead of freshwater during compaction increases the maximum dry unit weight and reduces the optimum moisture content. However, the data are sparse and the effects of soil plasticity on compaction when using saline water have not been thoroughly investigated. Additionally, most of the published literature deals with the use of water from inland salt lakes with very high salinity levels. This paper reviews the current literature, presents new data in which ocean water is used to condition soils during compaction, and investigates the importance of clay content when compacting soils with high salinity water. Results confirm that use of ocean water also increases optimum dry unit weight and decreases optimum water content. Ocean water appears to be as effective as highly saline water. The changes in compaction behavior are evident at clay contents as low as 10 percent.