Shear creep of epoxy at the concrete–FRP interfaces

This paper presents the results of experimental and analytical investigations of the long-term behavior of the epoxy used at the concrete–FRP interfaces. Double shear long-term test was performed on specimens composed of concrete blocks bonded to FRP sheets using epoxy. Three test replicates were examined under sustained shear stress for up to six month time period with two primary parameters: the shear stress level and the epoxy thickness. The investigation showed that shear stress level might have significant effect on the long-term behavior of epoxy at the concrete–FRP interfaces. Based on the experimental results, creep characteristics of epoxy in the concrete–FRP interfaces were evaluated. Finite element analysis was performed incorporating these creep characteristics to investigate the long-term deformations and stress redistributions in the test specimens. It was recognized that creep of epoxy might result in stress-redistribution at the concrete–FRP interfaces.