Steel fiber reinforced polymer (SRP) composite materials, which consist of continuous unidirectional steel wires (cords) embedded in a polymeric matrix, have recently emerged as an effective solution for strengthening of reinforced concrete (RC) structures. SRP is bonded to the surface of RC structures by the same matrix to provide external reinforcement. Interfacial debonding between the SRP and concrete is a primary concern in this type of application. This study aimed to investigate the bond characteristics between SRP and concrete determined by single-lap direct shear tests with different composite bonded lengths and fiber sheet densities (cord spacings). Specimens with medium density fibers failed mainly due to composite debonding, whereas those with low density fibers failed due to fiber rupture. Results of specimens that exhibited debonding were used to determine the bond-slip relationship of the SRP-concrete interface and to predict the full-range load response, which was in good agreement with the experimental results. A database of SRP-concrete direct shear tests reported in the literature was also established. Four analytical equations derived for fiber reinforced polymer (FRP)-concrete debonding were evaluated based on the database results and were found to predict the maximum load within approximately 15% error on average, however, they all underestimated the effective bond length.

中文翻译：

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钢纤维增强聚合物 (SRP) 与混凝土之间的粘结行为

钢纤维增强聚合物 (SRP) 复合材料由嵌入聚合物基体中的连续单向钢丝（帘线）组成，最近已成为增强钢筋混凝土 (RC) 结构的有效解决方案。SRP 通过相同的基体粘合到 RC 结构的表面以提供外部增强。SRP 和混凝土之间的界面脱粘是此类应用中的主要问题。本研究旨在研究 SRP 与混凝土之间的粘合特性，这些特性是通过单搭直剪试验确定的，具有不同的复合材料粘合长度和纤维板密度（帘线间距）。中密度纤维的试样主要由于复合材料脱粘而失效，而低密度纤维的试样则由于纤维断裂而失效。使用表现出脱粘的试样的结果来确定 SRP-混凝土界面的粘结滑移关系并预测全范围载荷响应，这与实验结果非常吻合。还建立了文献中报道的 SRP 混凝土直剪试验数据库。根据数据库结果评估了四个用于纤维增强聚合物 (FRP)-混凝土脱粘的分析方程，发现它们预测的最大载荷平均误差在 15% 以内，但是，它们都低估了有效粘合长度。还建立了文献中报道的 SRP 混凝土直剪试验数据库。根据数据库结果评估了四个用于纤维增强聚合物 (FRP)-混凝土脱粘的分析方程，发现它们预测的最大载荷平均误差在 15% 以内，但是，它们都低估了有效粘合长度。还建立了文献中报道的 SRP 混凝土直剪试验数据库。根据数据库结果评估了四个用于纤维增强聚合物 (FRP)-混凝土脱粘的分析方程，发现它们预测的最大载荷平均误差在 15% 以内，但是，它们都低估了有效粘合长度。