Steel rebars used in Reinforced Concrete (RC) elements may be subjected to corrosion due to aggressive environmental conditions. Rebar corrosion reduces the durability and the structural capacity of RC elements. On the other hand, since the steel rebars affect the magnetic fields, it is not preferred to be used in RC structures which is used to carry the equipment that propagate magnetic waves such as toll plazas on highways. For these reasons, the use of Fiber Reinforced Polymer (FRP) rebars is increasing, especially in RC infrastructure constructions. The objective of the present study is to investigate the bond behavior of Glass Fiber Reinforced Polymer (GFRP) rebar with a sand-coated outer surface in concrete using the arched beam test method. The concrete strength and the embedment length were chosen as variable parameters and 34 beam test specimens were tested in the laboratory. A comparative analysis of the crack patterns, the diagonal crack angles and the failure modes of the specimens is made. In addition, the experimentally determined bond-slip relationships were compared with different analytical models in the literature. Consequently, a bond-slip model, which takes into account CMR (Cosenza-Manfredi-Realfonzo) for the increasing part and mBPE (modified Bertero-Popov-Eligehausen) for the decreasing part, is proposed to be used in the numerical models of RC beams with sand-coated GFRP rebars. A prediction model for the bond strength is proposed, along with a recommendation for an upper bound value for the bond stress, which indirectly offers a minimum embedment length for a bond without slippage.

中文翻译：

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埋入混凝土中的涂砂 GFRP 钢筋弯曲粘结性能试验研究

钢筋混凝土 (RC) 元件中使用的钢筋可能会因恶劣的环境条件而受到腐蚀。钢筋腐蚀会降低 RC 元件的耐用性和结构能力。另一方面，由于钢筋会影响磁场，因此不优选用于承载传播磁波的设备（例如高速公路收费站）的RC结构。由于这些原因，纤维增强聚合物 (FRP) 钢筋的使用不断增加，特别是在 RC 基础设施建设中。本研究的目的是使用拱形梁测试方法研究外表面涂砂的玻璃纤维增​​强聚合物（GFRP）钢筋在混凝土中的粘结行为。选择混凝土强度和埋置长度作为变量参数，在实验室对34个梁试件进行了测试。对试件的裂纹形态、斜裂纹角度和破坏模式进行了对比分析。此外，将实验确定的粘结滑移关系与文献中的不同分析模型进行了比较。因此，建议在 RC 数值模型中使用一种粘结滑移模型，该模型在增加部分考虑 CMR (Cosenza-Manfredi-Realfonzo)，在减少部分考虑 mBPE (modified Bertero-Popov-Eligehausen)。带有涂砂 GFRP 钢筋的梁。提出了粘合强度的预测模型，以及粘合应力上限值的建议，这间接提供了无滑移粘合的最小嵌入长度。