Abstract The interfacial bond between the fiber-reinforced polymers tube (FRP-T) and its concrete core (CC) is necessary to transfer the loads from the FRP-T to the CC. In this study authors present an experimental investigation of the interfacial bond strength between the circular pultruded FRP-Ts (with or without sand-coating) and a CC. It also aims to evaluate the use of sand-coating as a bond enhancer to improve the interfacial bond strength of the concrete filled FRP tube members. Twelve (12) full-scale circular CFFT specimens with 200 mm length and 12,7 mm wall thickness were tested, with two different diameters (305 mm and 406 mm) and two different inner surface texture (sand-coated or not). The driving force and the slippage between the FRP-T and its CC were captured to plot the interfacial bond-slip relationships for each specimen. The experimental results showed that the measured interfacial bond stress between the pultruded FRP-T and its CC (without sand-coating) was varying from 0.022 MPa to 0.028 MPa then could therefore be neglected. Meanwhile, the interfacial bond strength of the same tube with sand-coating was varying from 0.43 MPa to 1.00 MPa. Consequently, sand-coating as a bond enhancer was proven to significantly improve the interfacial bond strength of the pultruded FRP-T. This paper also presents results from an analytical model and a F.E. simulation model of the interfacial bond-slip behaviour for CFFT members. Coulomb stick-slip friction model is used to characterise the interfacial connection behaviour between the FRP-T and its CC. Experimental, analytical and numerical results are consistent.

中文翻译：

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FRP 混凝土管粘结滑移行为的实验、分析和数值评估

摘要 纤维增强聚合物管（FRP-T）与其混凝土芯（CC）之间的界面结合是将载荷从 FRP-T 传递到 CC 所必需的。在这项研究中，作者对圆形拉挤 FRP-T（有或没有砂涂层）和 CC 之间的界面结合强度进行了实验研究。它还旨在评估使用砂涂层作为粘结增强剂以提高混凝土填充 FRP 管构件的界面粘结强度。测试了十二 (12) 个全尺寸圆形 CFFT 试样，其长度为 200 毫米，壁厚为 12.7 毫米，具有两种不同的直径（305 毫米和 406 毫米）和两种不同的内表面纹理（涂砂或未涂砂）。捕获 FRP-T 与其 CC 之间的驱动力和滑移，以绘制每个试样的界面粘合滑移关系。实验结果表明，测得的拉挤 FRP-T 与其 CC（无砂涂层）之间的界面结合应力从 0.022 MPa 变化到 0.028 MPa，因此可以忽略不计。同时，同一管涂砂的界面结合强度从 0.43 MPa 到 1.00 MPa 不等。因此，砂涂层作为粘合增强剂被证明可以显着提高拉挤 FRP-T 的界面粘合强度。本文还介绍了 CFFT 成员界面结合滑移行为的分析模型和有限元仿真模型的结果。库仑粘滑摩擦模型用于表征 FRP-T 与其 CC 之间的界面连接行为。实验、分析和数值结果是一致的。