Shear key joints are commonly used in constructions of precast concrete segmental bridges. Most researches focused on shear performance of the dry joints with the identical-strength concrete, leaving a research gap on that of composite joints between different concrete segments. This research aims to investigate shear behavior of shear key joint between reactive powder concrete and high strength concrete. Totally 12 specimens of single-keyed dry joint were tested, with the parameters of concrete compressive strength, steel fibers, and confining stress. The experimental results indicated that shear failure was observed, but crushing phenomenon occasionally occurred in composite joints in testing, which was confirmed by stress distribution from numerical simulation. In terms of shear capacity of composite joint, peak shear loads of reactive powder concrete specimens without steel fibers were enhanced by 10%–12% as increasing of concrete compressive strength, while those with steel fibers achieved 22%–25% enhancement. Nevertheless, a slight reduction of normalized shear strength was obtained because of its lower volume fraction of coarse aggregate. In numerical simulation, as increasing the concrete compressive strength of convex part, peak shear load was enhanced, but the increment rate of peak shear load decreased. Shear design formulae underestimated shear capacity of reactive powder concrete specimens with steel fibers, but the models proposed by Buyukozturk and Rombach gave accurate predictions on those without steel fibers.

剪力键缝通常用于预制混凝土分段桥的施工中。多数研究集中在相同强度混凝土干接缝的剪切性能上，而在不同混凝土节段之间的复合接缝上的研究空白。本研究旨在研究活性粉末混凝土与高强度混凝土之间的剪切关键接缝的剪切性能。总共测试了12个单键干接缝样品，并测试了混凝土的抗压强度，钢纤维和围压参数。实验结果表明，观察到剪切破坏，但是在试验中复合接头偶尔会出现压碎现象，这可以通过数值模拟的应力分布得到证实。就复合材料接头的剪切能力而言，随着混凝土抗压强度的提高，无钢纤维的活性粉末混凝土试样的峰值剪切载荷提高了10％–12％，而具有钢纤维的活性粉末混凝土试样的峰值剪切载荷提高了22％–25％。然而，由于其较低的粗骨料体积分数，使归一化剪切强度略有降低。在数值模拟中，随着凸部混凝土抗压强度的提高，峰值剪力增加，但峰值剪力增加率减小。剪切设计公式低估了具有钢纤维的活性粉末混凝土试样的剪切能力，但是Buyukozturk和Rombach提出的模型对没有钢纤维的模型给出了准确的预测。而使用钢纤维的人则提高了22％–25％。然而，由于其较低的粗骨料体积分数，使归一化剪切强度略有降低。在数值模拟中，随着凸部混凝土抗压强度的提高，峰值剪力增加，但峰值剪力增加率减小。剪切设计公式低估了具有钢纤维的活性粉末混凝土试样的剪切能力，但是Buyukozturk和Rombach提出的模型对没有钢纤维的模型给出了准确的预测。而使用钢纤维的人则提高了22％–25％。然而，由于其较低的粗骨料体积分数，使归一化剪切强度略有降低。在数值模拟中，随着凸部混凝土抗压强度的提高，峰值剪力增加，但峰值剪力增加率减小。剪切设计公式低估了具有钢纤维的活性粉末混凝土试样的剪切能力，但是Buyukozturk和Rombach提出的模型对没有钢纤维的模型给出了准确的预测。峰值剪切负荷增加，但峰值剪切负荷的增加率降低。剪切设计公式低估了具有钢纤维的活性粉末混凝土试样的剪切能力，但是Buyukozturk和Rombach提出的模型对没有钢纤维的模型给出了准确的预测。峰值剪切负荷增加，但峰值剪切负荷的增加率降低。剪切设计公式低估了具有钢纤维的活性粉末混凝土试样的剪切能力，但是Buyukozturk和Rombach提出的模型对没有钢纤维的模型给出了准确的预测。