Bond properties between polyvinyl chloride (PVC) tubes and wrapped textile reinforced fine concrete (TRC) shells

This paper experimentally investigated the bond properties between the outer walls of polyvinyl chloride (PVC) tubes and wrapped textile reinforced fine concrete (TRC) shells. A total of 20 PVC tube column specimens wrapped with TRC shells were prepared for interface bonding performance test. Four test key parameters such as the thin-walled component size, the number of grooves on interface, the ratio of perforated holes for PVC tubes, the number of shear connectors were evaluated in this study. The results of the study indicated that the bonding properties between PVC tubes and wrapped TRC shells were significantly enhanced by embedding stainless steel nails as shear connectors and roughening the interface through perforating and grooving the PVC tubes. Compared to specimens without interface treatment, the bond strength between PVC tubes and wrapped TRC shells increased the most when grooves were fabricated and stainless steel nails were embedded simultaneously at the bond interface in this study, and the maximum increment could reach up to 37.8% and 41.5% for PVC tube specimens with 160 mm and 200 mm diameters, respectively. To further analyze the bond properties, an analytical model was established based on the experimental data and theoretical analysis. The effects of shear connectors and interface roughness were incorporated in the model, and the predicted bond stress-slippage responses from the proposed model aligned well with the experimental data.