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Abstract
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Soft clay soils exhibit undesirable properties such as low bearing capacity, poor workability, high compressibility, dispersivity and expansive behavior which have irreparable damage on the structures built on them. These properties are influenced by the behaviour of the clay minerals. Montmorillonite clay mineral has an expansive lattice structure with high cation exchange capacity and swelling potential, whereas Kaolinite and Illite have a relatively low cation exchange capacity attributed to their non-expansive nature. Chemical stabilization is one of the ground improvement techniques which has been successfully used to improve engineering properties of fine-grained soils. In recent years, researchers have proposed that calcium carbide residue is a promising soil stabilizing material since it is rich in Ca(OH)2, has larger specific surface area, and elevated pH values. This study presents a detailed investigation on the effects of lime, calcium carbide residue (CCR) and ground granulated blast furnace slag (GGBFS) on the improvement of the strength and swelling properties of problematic clay soils. Lime application increases the overall cost of the project due to its costliness, on the contrary, CCR and GGBFS are industrial by-products which can be used for clay soil stabilization instead of hauling them to landfills. The utilization of these industrial waste materials could result in considerable reduction in construction costs and disposal challenges. Different compositions of admixtures were utilized to investigate strength properties of the clay soils using the unconfined compressive strength (UCS) test. The specimen’s compositions varied from 2% to 8% by dry weight of soil for lime, CCR and GGBFS only mixtures, and 4% to 16% by dry weight of soil for lime-GGBFS and CCR-GGBFS blended mixtures. The specimens were molded at optimum moisture content and were allowed to cure for 7 and 28 days before testing. The maximum unconfined compressive strength results for
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