Experimental study of fracture properties of interfacial transition zone by three-point bending tests on granite-mortar hybrid beams

Abstract

The three-point bending tests were performed on the granite-mortar hybrid beam specimens to investigate the fracture properties of the interfacial transition zone (ITZ). Their curves of load versus crack mouth opening displacement were obtained. The peak load ratio and the fracture energy ratio between the hybrid specimen and the mortar specimen with the same water-cement ratio in mortar were introduced to characterize the weak ITZ fracture properties. The effects of the water-cement ratio in mortar, interface roughness and silica fume content in interfacial agent on the peak load and fracture energy were investigated and their relations were also fitted approximately. The results showed that both the peak load and fracture energy can be significantly increased by reducing the water-cement ratio in mortar and by increasing the granite-mortar interface roughness. However, the silica fume content has complicated nonlinear effects on the peak load and fracture energy. The optimal silica fume content is about 6%, which makes the best bonding performance between granite and mortar.