后浇自密实混凝土拼接叠合梁抗弯性能试验研究

Experimental Study on Flexural Performance of Post-cast Self-compacting Concrete Spliced Composite Beams

设计制作了5根后浇自密实混凝土拼接叠合梁,预制部分用C30普通混凝土,后浇部分用C30自密实混凝土;同时设计了1根用C30普通混凝土浇筑的整浇梁作为对照梁。通过抗弯性能试验,得到了试验梁的跨中挠度、裂缝发展规律和破坏特征。结果表明:拼接叠合梁的受弯破坏形态与对照梁类似,均为适筋破坏;增大拼接叠合面的粗糙度可以提高拼接叠合梁的抗弯承载力,但抗弯承载力与粗糙度不成正相关关系,这与预制部分混凝土中的粗骨料粒径和级配有关;采用箍筋加密和拼接叠合面插筋的方式均可以保证拼接叠合梁的抗弯承载力。

Five post-cast self-compacting concrete spliced composite beams were designed,the precast part was poured with C30 ordinary concrete,and the post-cast part was poured with C30 self-compacting concrete.In addition,one cast-in-place beam poured with C30 ordinary concrete was designed as the control beam.Through the flexural performance test,the mid-span deflection,crack development law and failure characteristics of test beams were obtained.The results show that the flexural failure form of the spliced composite beam is similar to that of the control beam,both of which are the appropriate reinforcement failure.Increasing the roughness of the spliced composite surface can improve the flexural capacity of the spliced composite beam,but the flexural capacity is not positively related to the roughness,which is related to the particle size and gradation of coarse aggregate in the precast concrete.Both stirrup encryption and spliced reinforcement can improve the flexural capacity of the spliced composite beam.