In this article, the durability of the interfacial bonds between epoxy and concrete during hygrothermal exposure was investigated. Through the application of a silane coupling agent, we examined the hypothesis that hydrogen bonding plays a large role in the degradation of the interfacial bond between epoxy and concrete, in which displacement of epoxy with water induces the disruption of the interfacial hydrogen bond. This hypothesis suggests that durability can be enhanced with the use of a silane coupling agent by changing the interfacial hydrogen bonds to stronger covalent bonds. The slant shear test results show that the durability of the interfacial bond was significantly enhanced with the use of an epoxy-functional silane coupling agent. Spectroscopic features using FTIR confirmed the changes in chemical nature of concrete after the silane modification. By calculating the percent contribution to the bond strength for each set of specimens, it was confirmed that the silane application improved the durability with exposure for all conditions; however, over time the improvement diminished. POLYM. ENG. SCI., 2013. (c) 2012 Society of Plastics Engineers