A new grip adaptor, made of an engineering plastic Cast Polyamide 6 (PA6G), was developed for tension testing of FRP reinforcing bars. The new adaptor offers several advantages over conventional anchors, including the ease of application and reuse, being economical, no need for skilled labor, smaller difference between the hardness of the adaptors and sample. Bars with three different diameters (6, 8 and 12 mm), three types of fiber (Carbon, Glass and Basalt) and four types of surface texture (ribbed, wound, fine-sand coated and coarse-sand coated with widely-spaced wrapping) were tested to failure under uniaxial tension. Two identical bars were tested for each combination of parameters (fiber type, surface texture and bar diameter), one with PA6G and the other with grout-filled steel anchors. The tests indicated that the proposed method was able to ensure FRP bars to reach their tensile capacities and fail by rupture without crushing in the gripping regions and pull-out from the jaws of the testing machine. The modulus of elasticity, tensile strength and ultimate strain values of the bars with PA6G anchors were in rather close agreement with the respective values of specimens with conventional steel anchors. This close agreement, i.e. mostly a difference below 5%, implies the success of the proposed method. Among all tested bars, only the ribbed ones failed in the gripping regions in the presence of both anchors as a result of the limited contact surface (rib area), pointing out the need for the use of longer anchors for ribbed bars.

中文翻译：

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用于玻璃钢钢筋拉伸试验的工程塑料夹持机构

开发了一种由工程塑料浇铸聚酰胺 6 (PA6G) 制成的新型夹具适配器，用于 FRP 钢筋的拉伸测试。与传统固定器相比，新型适配器具有多种优势，包括易于应用和重复使用、经济、无需熟练劳动力、适配器与样品之间的硬度差异较小。三种不同直径（6、8 和 12 毫米）、三种纤维（碳纤维、玻璃和玄武岩）和四种表面纹理（罗纹、缠绕、细砂涂层和大间距包裹粗砂涂层）的棒材) 在单轴拉伸下进行了失效测试。针对每种参数组合（纤维类型、表面纹理和钢筋直径）测试了两个相同的钢筋，一个使用 PA6G，另一个使用灌浆钢锚栓。测试表明，所提出的方法能够确保 FRP 钢筋达到其拉伸能力，并因断裂而失效，而不会在夹持区域被压碎并从试验机的钳口中拉出。PA6G 锚杆的弹性模量、拉伸强度和极限应变值与常规钢锚杆试样的相应值相当接近。这种接近一致，即大部分差异低于 5%，意味着所提出的方法是成功的。在所有测试的钢筋中，由于接触面（肋面积）有限，只有带肋的钢筋在两个锚固件存在的情况下在夹持区域失败，这表明需要对带肋钢筋使用更长的锚固件。