FRP rebars offer notable advantages over steel rebars for internal concrete reinforcement. However, since the technique is relatively recent, further durability investigations are needed to better understand degradation mechanisms and provide optimized safety coefficients. While several researchers have explored the durability of FRP rebars, only few have examined the evolution of the FRP-concrete interfacial bond. This study aims to present investigations into the durability of the bond between GFRP rebars and high-strength concrete. The GFRP-to-concrete bond behaviour was experimentally studied, focusing on the combined effects of thermally accelerated ageing in alkaline environment and sustained loading. First, the pull-out sample geometry and initial characterizations of the interface will be introduced. Then, the ageing protocol will be presented. In this protocol, some pull-out samples were subjected to sustained load in combination with alkaline ageing. The evolution of the residual interfacial properties over ageing is finally presented, allowing for a discussion on the influence of sustained load on the aging process.