气泡膜成型的预制混凝土构件结合面受剪性能

“等同现浇”装配式混凝土结构通过后浇混凝土将预制混凝土构件连接形成整体，预制构件与后浇混凝土之间的结合面往往需要通过各种工艺形成粗糙面，以保证新、老混凝土的黏结性能。提出一种采用气泡膜成型的预制构件结合面做法，并通过试验研究其受剪性能。试件按双剪试验设计，考虑混凝土强度等级、结合面连接钢筋配置等参数的变化，主要从承载力及延性方面与整体浇筑试件进行对比。试验及分析结果表明，气泡膜成型试件受剪承载力满足设计要求，为整体浇筑试件受剪承载力的71%～93%，延性两者则基本相当；混凝土强度等级的提高可增强试件受剪承载力，连接钢筋可有效改善试件受剪承载力并显著提高延性，由于整浇试件偏弯剪受力状态，导致连接钢筋对整浇试件受剪性能的改善作用较气泡膜成型试件更为明显；在连接钢筋配筋率基本相当的前提下，建议采用直径较小、间距较密的钢筋配置方案。

Shear bearing performance of precast concrete component interface by bubble film

Emulative precast concrete structure connects the precast concrete components to form a whole by cast-in-situ concrete. The interfaces between the precast components and the local cast-in-situ concrete are often formed to be rough by various processes to ensure the bonding properties of the new and old concrete. A precast concrete component interface by the bubble film is proposed and its shear performance is studied through experiments. Double-shear specimens, considering different concrete strength grades and the connecting steel bar at the interface, were designed to compare with the cast-in-situ specimen mainly from the aspects of the bearing capacity and the ductility. The experimental and analysis results show that the shear capacity of the specimen processed by bubble film exceeds the design requirements, and can reach 71%～93% of that of the cast-in-situ specimen. Increasing concrete strength grade can improve the shear capacity. Connecting steel bars can effectively improve the shear capacity of specimens and significantly improve the ductility. Since the cast-in-situ specimens are in shear-flexure state，the effect of connecting steel bars on the shear resistance of the cast-in-situ specimens is more obvious than that of the specimens processed by bubble film. Under the basically same reinforcement ratio of the connecting steel bars, the reinforcement configuration with smaller diameter and tight spacing is recommended.