Effect of the addition of Industrial Materials on the Properties of Expansive Soil in the Al-Azraq Area, Jordan

This study aims to investigate the stabilization of expanded bentonite-rich clay soil in Al-Azraq area in Jordan. This is achieved by mixing soil with different proportions of four types of stabilizers; lime, phosphatic clay, cement kiln dust (CKD), and sandstone. The in-dex properties of Al-Azraq soil have been investigated through various tests. The chemical and mineralogical compositions of materials have been examined. Compaction, California bearing ratio, and unconfined compression tests are used to assess the engineering proper-ties of the stabilized soil. The results revealed that with the addition of 5% lime, 10% phos-phatic clay, 7.5% CKD, and 10% sandstone, the plasticity index reduced from 60% to 17.2%, 18.47%, 17.52%, and 22.70%, respectively. The maximum dry density increased with the addition of 5% lime from 1.19 mg/cm3 to 1.58 mg/cm3. The optimum moisture content decreased from 40.1% to 32.4% with the addition of 10% sandstone. The California bearing ratio increased from 9% to 17.5% with the addition of 7.5% CKD. The unconfined compression strength improved significantly with the addition of stabilizers due to chemical reactions that resulted in the production of binding compounds. The addition of 5% lime and 7.5% CKD, according to the results, is responsible for the formation of new product binding materials that improve mechanical strength via the pozzolanic reaction. The possibility of reusing by-product materials such as CKD and phosphatic clay as non-traditional soil stabi-lizers could reduce the amount of these materials destined as waste.