ECC-混凝土黏结界面断裂试验研究

采用双材料楔入劈拉试件,研究了超高韧性水泥基复合材料(ECC)与混凝土黏结界面的断裂性能,讨论了最粗糙面、次粗糙面和光滑面3种界面粗糙度对界面破坏模式及断裂韧度的影响;结合界面力学理论,分析了裂缝偏折破坏与界面破坏的发生及界面粗糙度对裂缝偏折的影响.结果表明:对于最粗糙和次粗糙界面试件,以骨料-ECC黏结界面破坏及小角度偏折界面破坏为主,而光滑界面试件以界面破坏为主;提高黏结界面粗糙度可以使黏结界面的强度有一定程度的提高,并且界面裂缝在加载过程中易于偏向ECC,可实现ECC的裂缝捕捉,因此,当黏结界面受力状况不明确时,应尽量提高ECC-混凝土界面粗糙度,避免发生界面破坏,从而最大地发挥ECC效用.

Experiment Study on Fracture Property of ECC Concrete Interface

Based on bi material wedge splitting test(WST), the fracture property of interface between engineering cementitious composites and concrete was investigated. The effect of three different levels of roughness on ECC concrete interface fracture properties and failure mode was also discussed. By adopting interface mechanics, both kinked crack failure and interface failure and the influence on kinked crack failure by different interface roughness were analyzed. It is discovered from the study that interface failure occurs in the specimens with smooth interface while interface failure with small angle deflection occurs in the specimens with rough interface. When the interfacial roughness is improved, bonding interface strength can be enhanced to a certain extent, and the interface crack during the loading process kinks into ECC more easily due to interface crack trapping mechanism can be guaranteed to achieve. In practical engineering applications, interfacial roughness should be enhanced to avoid interface failure and ECC should be used if the type of loading is unknown.