Effects of Sustained Loading and Temperature on a Concrete–Epoxy Bonded Interface

Abstract

The mechanical behavior of the concrete–epoxy bonded interface is of high importance in concrete strengthening and repair systems. This paper presents the effects of cure time, sustained load, and different temperatures on the time-dependent deformation of a concrete–epoxy interface (CEI) and on the fracture behavior of the CEI at room temperature. Notched three-point bending specimens were used for this experimental study. Elevated temperatures during sustained loading increased the crack mouth opening displacement (CMOD) of the CEI, as did less curing time prior to sustained loading. Both of these results can be attributed to viscoelastic deformation of the epoxy. In fracture tests conducted after the sustained loading period, it was observed that the ultimate load and total fracture energy of the CEI specimens asymptotically decreased in comparison to control specimens that did not undergo sustained loading. Image analysis of the fracture surfaces showed an increase in the incidence of the interfacial failure mode with sustained loading, corresponding to reduced bond performance.