新旧混凝土叠合面抗剪性能研究

新旧混凝土叠合面的剪切强度是衡量界面黏结性能的最重要指标。基于Z形黏结试件剪切试验,研究了不同叠合层材料、不同界面处理方式、不同槽口形式下的叠合界面抗剪性能。结果表明,UHPC试件表现出较好的界面抗剪能力,其承载力均高于自密实试件。对于槽口构件,槽口连接形式能提高叠合面抗剪承载力,其中梯形槽口对界面抗剪承载力提升效果更为显著。槽口形式对UHPC材料与C30混凝土界面抗剪能力的影响相较于其对自密实材料与C30混凝土界面抗剪能力的影响更为显著。对于有锚固钢筋的试件,增大锚固钢筋的锚固长度可以提高UHPC材料与C30混凝土界面抗剪能力;对于无锚固钢筋无槽口试件,气泡纸粗糙面处理可以改善UHPC试件的变形能力。

Research on the Shear Resistance of Combined Interface of New and Old Concrete

The shear strength of old and new concrete combined interface is the most important index to measure the interfacial bonding property.Based on the shear test of z-shaped bonding specimens,the shear resistance of composite interface with different laminated materials,different interface treatment methods and different notches was studied.The results show that the UHPC specimens exhibit good interface shear resistance and their bearing capacity is higher than that of self-compacting specimens.For the notched specimens,the notched joint can improve the shear strength of the composite surface,among which the trapezoidal notched joint has more significant effect on the shear strength of the interface.The influence of notch form on the shear resistance of UHPC material and C30 concrete interface is more significant than that of self-compacting material and C30 concrete interface.For the specimens with anchorage reinforcement,increasing the anchorage length of the anchorage reinforcement can improve the shear resistance of the interface between UHPC material and C30 concrete.For non-anchorage steel bar notched specimens,bubble paper rough surface treatment can improve the deformation capacity of UHPC specimens.