Experimental, analytical, and code‐based assessment of geopolymer concrete‐filled unplasticized polyvinyl chloride tubes subjected to axial compression

This study investigates the experimental, analytical, and code‐based assessment of geopolymer concrete‐filled unplasticized polyvinyl chloride (UPVC) tubes (GPCFUPVCTs) subjected to axial compression. A total of 24 GPCFUPVCTs were prepared and tested. The study examines the influence of concrete strength (40 and 60 MPa), aspect ratio of specimens ( H / D equal 2 and 4), and UPVC thickness (4.8 and 7.6 mm) on the ultimate strength of GPCFUPVCTs. Based on the results, the ultimate strength of GPCFUPVCT specimens increased for higher concrete infill strength and greater UPVC tube thickness, while it decreased with a higher aspect ratio. Additionally, existing literature on concrete‐filled thermoplastic (polyethylene, PVC, and UPVC) tube (CFTT, 523 specimens) is utilized to complement the experimental findings, providing a comprehensive analysis of CFTT performance. Experimental results from this study, along with data from existing literature, were used to evaluate the applicability of the nine design codes, includingACI, CISC, BS, DBJ, AASHTO, AISC, EC4, AS‐NZS, and AIJ. These international codes offer equations for predicting the performance of concrete‐filled steel tubes, but they do not provide formulations for CFTT. The findings revealed that EC4 and AS‐NZS predict the available experimental data more accurately, while the experimental ultimate strength values are more scattered compared to the calculated values using ACI. Moreover, EC4 and AS‐NZS codes with some modifications are suggested for the strength design of CFTTs. Finally, formulations according to the experiments and the EC4 code are proposed, offering satisfactory alignment with the experimental data.