界面处理对预制UHPC与现浇NC界面抗剪性能的影响

Effect of Interfacial Treatment on Shear Properties of Precast UHPC and Cast-in-Place NC

关键词:  预制超高性能混凝土  界面处理  组合试件  双面剪切试验

Key words:  precast ultra-high performance concrete  interfacial treatment  composite specimen  bi-surface shear test

摘要:

对未处理和经喷砂、凿毛、切槽界面处理后的预制超高性能混凝土（UHPC）与现浇普通混凝土（NC）组合试件进行双面剪切试验，记录加载过程中的剪切荷载与界面滑移，通过剪切荷载-界面滑移曲线分析不同界面处理方式对组合试件抗剪性能的影响.结果表明：界面处理显著提高了预制UHPC与现浇NC组合试件的界面抗剪性能；不同界面处理方式下组合试件的破坏模式主要分为3种；采用边长18 mm正方形钢丝网格凿毛处理的组合试件界面抗剪强度与抗剪刚度均最大，其界面抗剪强度为未处理界面试件的4.69倍；凿毛与切槽处理使组合试件拥有较好的界面抗剪性能，表现为延性破坏；界面粗糙度相近但界面处理方式不同的组合试件抗剪性能表现出明显差异；各组试件界面抗剪强度与抗剪刚度变化趋势大致相同.

Abstract:

Bi-surface shear tests were carried out on precast ultra-high performance concrete（UHPC） and cast-in-place normal concrete（NC） composite specimens including untreated， sandblasted， rough chiseled and slotting interfacially treated specimens. The shear load and interface slip were recorded during loading process. Shear load-interface slip curves were used to analyze the effect of different interfacial treatment on the shear properties of the composite specimens. The results show that the interfacial treatment significantly improves the shear properties of the precast UHPC and cast-in-place NC composite specimens，failure modes of composite specimens are mainly divided into three catagories. The interfacial bonding shear strength and stiffness of the 18 mm steel-wire-mesh chiseling composite specimens are the highest， and the strength is 4.69 times that of the untreated interface. Chiseling interfacial treatment and slotting interfacial treatment make the composite specimens have good shear properties and show ductile failure. The shear properties of specimens with similar average sand filling depth but different interfacial treatment groups show obvious differences. The variation trend of shear strength and shear stiffness of different groups are about the same.