超高性能混凝土-石材界面黏结性能试验研究

Experimental Research on Bonding Performance of Interface Between Ultra-High Performance Concrete and Stone

超高性能混凝土(UHPC)加固修复既有石结构中,UHPC与石材之间优异的黏结性能是保证加固效果的关键。因此,为探究UHPC-石材界面的黏结性能,通过劈裂抗拉试验和双L型剪切试验,考察不同界面处理方式对UHPC-石材界面黏结性能的影响。结果表明,UHPC-石材界面破坏模式主要分为三种,其中发生模式C破坏(石材UHPC破坏)时界面黏结强度最大。界面键槽处理方式能显著提高UHPC-石材界面黏结强度、界面剪切刚度,且在改变破坏形态的同时有效提升试件的延性,当键槽深度为20 mm时,试件表现出较好的界面黏结性能。另外,试件剪切荷载-位移曲线包含滑移前阶段和滑移后阶段,凿毛试件在滑移后阶段没有经历塑性变形。相同界面处理方式下,UHPC-石材的界面抗剪强度与界面劈裂抗拉强度呈正相关关系。

In the reinforcement and repairmen of existing stone structures by ultra-high performance concrete(UHPC),the excellent bonding performance between UHPC and stone is the key to ensure the reinforcement effect.Therefore,in order to explore the interface bonding performance between UHPC and stone,the effects of different interface treatment methods were investigated by splitting tensile test and double L-shaped shear test.The results show that the failure modes of the interface between UHPC and stone are mainly divided into three types.The interface bonding strength is the largest when mode C failure(stone UHPC failure)occurs.The interface groove treatment method significantly improves the interface bonding strength and interface shear stiffness of UHPC-stone specimens.Simultaneously,the interface groove treatment method effectively improves the ductility of specimens while changing the failure mode.When the groove depth is 20 mm,specimens show better interface bonding performance.In addition,the shear load-displacement curve of specimen includes the pre-slip stage and the post-slip stage,and the chisel specimen does not experience plastic deformation in the post-slip stage.Under the same interface treatment method,the interface shear strength between UHPC and stone is positively correlated with the interface splitting tensile strength.