Assessment of residual strength of concrete girders rehabilitated using NSM CFRP with cementitious adhesive made with graphene oxide after exposure to fatigue loading

This paper presents the residual strength of reinforced concrete (RC) beams strengthened and repaired by using near-surface mounted (NSM) carbon fibre reinforced polymer (CFRP) with innovative high-strength self-compacting non-polymer cementitious adhesive (IHSSC-CA) and epoxy adhesive after being subjected to fatigue loading. Cementitious materials and graphene oxide were used to synthesise the IHSSC-CA. Ten full-scale beams were manufactured and tested under four-point loading with different loading histories. Five beams were tested under monotonic loading up to failure, and another five beams were then tested under fatigue loading at service load levels up to failure or 3 million cycles, whichever happened first. The fatigue load range and frequency used in this study for testing the beams were designed to simulate the typical fatigue loading and frequency of an actual RC bridge girder under service loading conditions. The effect of fatigue loading was determined by comparing the performance of beams before and after fatigue loading. Finally, 3-D laser profilometry analyses was used to study the deformation of the CFRP strips after fatigue loading. The findings confirm the effectiveness of using IHSSC-CA to strengthen and repair RC beams with NSM CFRP system.