先浇UHPC-后浇普通混凝土气泡膜式结合面受剪性能试验研究

先浇UHPC-后浇普通混凝土气泡膜式结合面具有规模化应用于预制UHPC-普通混凝土组合构件的潜力。为研究先浇UHPC-后浇普通混凝土气泡膜式结合面的受剪性能，考虑气泡直径25 mm以下的三种气泡膜结合面规格、有无销栓钢筋作用的影响，设计并制作了6个先浇UHPC-后浇普通混凝土气泡膜式结合面试件、2个现浇对比试件及2个光面式结合面试件，开展受剪性能试验研究，比较了试件的破坏形态、荷载-位移曲线和抗剪强度等，提出了先浇UHPC-后浇普通混凝土气泡膜式结合面受剪承载力计算式。结果表明：先浇UHPC-后浇普通混凝土气泡膜式结合面破坏主要发生于普通混凝土一侧，大尺度气泡膜（气泡直径25 mm）形成的结合面受剪承载力相对较高，建议的受剪承载力计算式基本可用于评估气泡直径在25 mm以下的先浇UHPC-后浇普通混凝土气泡膜结合面的受剪承载力。

Experimental study on shear performance of bubble groove interface between precast UHPC and post cast normal concrete

The bubble groove interface between precast UHPC and post cast normal concrete has the potential to be widely applied in precast UHPC-normal concrete composite components. To study the shear performance of bubble groove interfaces between precast UHPC and post cast normal concrete with consideration of the effect of sizes of bubble grooves under 25 mm and dowel rebars, six composite specimens with bubble groove interfaces, two monolithic reference specimens and two composite specimens with flat interfaces were designed and manufactured. Shear tests were conducted. The failure modes, load-displacement curves and shear strength of different specimens were compared. A theoretical equation was proposed to calculate the shear resistance of the bubble groove interfaces between precast UHPC and post cast normal concrete. The results show that damage mainly occurs at the normal concrete side. The interface formed by large-sized bubble wraps (25 mm) has a relatively high shear resistance. The proposed theoretical equation can generally be used to estimate the shear resistance of bubble groove interface between precast UHPC and post cast normal concrete, where the diameter of the bubbles is smaller than 25 mm.