Experimental study on bond behavior of interface between fiber-reinforced polymer grids and concrete substrate

Abstract The aim of this study is to investigate the bond behavior of the interface between fiber-reinforced polymers (FRP) grids and concrete substrate. The examined parameters were as follows: (a) FRP grid widths (50, 100, and 150 mm); (b) FRP grid types (basalt, glass, and carbon FRP grids); (c) bonding material types (polymer cement mortar and epoxy resin); (d) FRP product types (FRP grids and sheet). Sixty bonded joint specimens were fabricated and subjected to single-shear experimental tests. The results indicated that the bond behavior of the FRP grid–concrete interface was significantly influenced by the width ratio of the FRP grids to concrete specimen, FRP grid stiffness, and bonding material type. In comparison with the FRP sheet–concrete interface, the FRP grid–concrete interface possessed significantly higher interfacial fracture energy, even though the stress transfer mechanism of this interface was more complicated. Additionally, based on the regression analysis of experimental data, empirical models for the width factor, bond–slip relationship, effective bond length, and bond strength of the FRP grid–concrete interface were developed.