EXPERIMENTAL STUDY ON TREATMENT OF OVER-WETTED CLAYS USING CALCIUM CHLORIDE

摘要

In the highway construction in the south of Jiangsu Province, China, over-wetted clays are commonly encountered. Since this type of soil has higher water content than the optimum water content, it needs to be properly treated before being used as embankment filling material. Binders like lime, Portland cement, and fly ash are commonly used to stabilize the over-wetted soils. In this paper, a new treatment method using solid calcium chloride, which is a chemical reaction product from waste calcium carbides, is proposed. A series of laboratory experiments were carried out to investigate the treatment effectiveness of calcium chloride additive with content of 0.5%-12%. The test results show that with a relatively high content of calcium chloride additive, the water content of the treated soil could be reduced by 42% and the unconfined compressive strength (UCS) of the treated soil with varying contents of calcium chloride increased by 22%-82%,.compared to the untreated case. Besides, the maximum dry density increased while the optimum water content decreased, which is similar to the phenomenon by increasing compaction energy. It is also found that when the content of calcium chloride was over 8%, UCS decreased, which indicates there is likely to exist an optimum content value. It is expected that the solid calcium chloride can be used as a binder to treat the over-wetted soils.