Effect of corrugated pipe diameters on bonding properties of Fe-SMA rebar and mortar after resistive heating

The impact of temperature activation on bonding performance is crucial in the application of iron-based shape memory alloys (Fe-SMAs). This study investigated the bonding properties of Fe-SMA rebar and mortar within various corrugated pipes, considering different diameters and heating temperatures. The influence of corrugated pipe diameter , Fe-SMA rebar diameter, and heating temperature on bonding properties was examined. The findings indicate that heating the Fe-SMA rebar rapidly to 200 °C concentrated heat mainly at the bonding interface, while maintaining a low temperature on the corrugated pipe surface. Increasing corrugated pipe diameter enhanced the binding force of Fe-SMA rebar, resulting in a significant increase in parameters such as ultimate bond strength and bond energy dissipation . The beneficial effect from increased corrugated pipe diameter was more pronounced after resistive heating, notably mitigating the reduction in ultimate bond strength. With the diameter of the Fe-SMA rebar increased, the ultimate bond strength decreased noticeably. Regardless of whether Fe-SMA was heated, the decrease in ultimate bond strength due to diameter change remained consistent. For both 10 and 16 mm Fe-SMA rebar diameters, the ultimate bond strength of specimens after 200 ℃ was reduced by about 10 % compared to specimens at normal temperature. Additionally, prediction models for bond-slip equations and ultimate strength were proposed, offering guidance for future investigations. • The bond properties between Fe-SMA rebars and mortar after resistance heating were investigated. • The specimens after 200 °C could still maintain a high ultimate bond strength retention of 90 %. • A larger pipe diameter mitigated the decline in ultimate bond strength caused by resistive heating. • The prediction models for the ultimate bond strength and the bond-slip curves were provided.