hemical Stabilization of Sustainable Subbase by Addition of Cement and Cement Kiln Dust

Soil stabilization has obtained significant attention to overcome challenges associated with weak soils. These efforts focus on improving soil properties, achieving economic benefits, and reducing environmental impacts. This study aims to evaluate the efficiency of using waste or by-product materials to improve the characteristics of subbase layers through chemical stabilization, with a particular focus on reducing construction costs and enhancing structural performance. The methodology included the use of the Cement Kiln Dust (CKD) and ordinary Portland cement (OPC) as chemical stabilizers for two types of subbase materials(Type B and Type C). The percentage of stabilizers for each mixture was 7% by dry weight of subbase; three stabilizer combinations were used: 100% OPC, 100% CKD, and a 50/50 blend of OPC and CKD. Laboratory tests were conducted, including sieve analysis, modified Proctor, California Bearing Ratio , Atterberg limits, and unconfined compressive strength tests to assess the properties of the stabilized soils. The results showed that a mixture of OPC and CKD in equal proportions significantly enhanced the compressive strength of the subbase materials,performance was improved and the required thickness of pavement layers can be decreased, leading to a significant decrease in overall construction cost.