Semnan University Press Journal of Transportation Infrastructure Engineering 2423-5350 10 1 2024 05 21 Effects of Simultaneous Use of Crumb Tires and Fly Ash on the Shear Behavior of Encased Stone Columns: A Laboratory Study Effects of Simultaneous Use of Crumb Tires and Fly Ash on the Shear Behavior of Encased Stone Columns: A Laboratory Study 63 79 8735 10.22075/jtie.2024.34022.1671 FA Saeed Negari Department of Civil Engineering, Yazd University, Yazd, Iran Maryam Mokhtari Department of Civil Engineering, Yazd University, Yazd, Iran Journal Article 2024 05 05 Applying stone columns (SCs) is an economical method to improve loose soil. This laboratory study is conducted on the effects of simultaneous use of crumb tire (CT) and fly ash (FA) on the shear behavior of SCs encased with geotextile and fiber-reinforced polymer (FRP) in soft clay. A large-scale direct shear device was utilized to do the desired tests. The samples were exposed to normal stress values of 20, 40, and 70 kPa. First, optimal percentages of CT and FA were determined to be used with granular materials in the SCs. The impact of installing ordinary reinforced and unreinforced SCs on the shear behavior of the assembly was examined. Installing the SCs in soft clay bed and adding the CT-FA composite to the SC materials increased the shear strength. Supplementing the CT-FA composite to the SC materials increased shear strength of the assembly to 4.6%-10%. The shear strength rose more than twice when the normal stress increased from 20 kPa to 70 kPa and it was mobilized more since CT-FA composite is present. It increased due to a rise in the replacement ratio of the SCs in the assembly. By installing the ordinary composite SCs in clay bed under the normal stresses of 20 kPa and 70 kPa, the shear strength increased to 34% and 41.7% and it would rise in the encased mode more than in the ordinary mode. Furthermore, the FRP-based reinforcement enhanced the shear strength more than the geotextile reinforcement did. Applying stone columns (SCs) is an economical method to improve loose soil. This laboratory study is conducted on the effects of simultaneous use of crumb tire (CT) and fly ash (FA) on the shear behavior of SCs encased with geotextile and fiber-reinforced polymer (FRP) in soft clay. A large-scale direct shear device was utilized to do the desired tests. The samples were exposed to normal stress values of 20, 40, and 70 kPa. First, optimal percentages of CT and FA were determined to be used with granular materials in the SCs. The impact of installing ordinary reinforced and unreinforced SCs on the shear behavior of the assembly was examined. Installing the SCs in soft clay bed and adding the CT-FA composite to the SC materials increased the shear strength. Supplementing the CT-FA composite to the SC materials increased shear strength of the assembly to 4.6%-10%. The shear strength rose more than twice when the normal stress increased from 20 kPa to 70 kPa and it was mobilized more since CT-FA composite is present. It increased due to a rise in the replacement ratio of the SCs in the assembly. By installing the ordinary composite SCs in clay bed under the normal stresses of 20 kPa and 70 kPa, the shear strength increased to 34% and 41.7% and it would rise in the encased mode more than in the ordinary mode. Furthermore, the FRP-based reinforcement enhanced the shear strength more than the geotextile reinforcement did. https://jtie.semnan.ac.ir/article_8735_da39518781d0bb0b635cb382e55b4443.pdf