3D acid diffusion model for FRP-strengthened reinforced concrete structures: Long-term durability prediction

摘要

Fibre-reinforced polymer (FRP) composites have been utilised as promising and popular solutions to strengthen existing reinforced concrete (RC) structures. Due to the increasing industrial activities, growing population and climate change, corrosive environments (e.g. acid rains) that diminish the durability of FRP-strengthened RC structures are becoming more common. The long-term durability of structures in these corrosive environments is central to the success of any strengthening technique. Despite this urgency, very limited research data is available regarding the degradation of RC structures strengthened with the FRP in acidic environments. This paper evaluates the impact of sulphuric acid on the performance of externally bonded FRP-strengthened RC structures and investigates the long-term behaviour of concrete, FRP composite, and the FRP-concrete interface. The acid diffusion mechanism within the FRP-concrete bond system is studied with the establishment of both one-dimensional (1D) and three-dimensional (3D) models. Moreover, a reduction factor UM accounting for the degrading effect of acid, is proposed to predict the retained bond strength at the FRP-concrete interface. The proposed models provide a theoretical basis for the durability design and the service life prediction of FRP-strengthened RC structures when subjected to acid attack. (C) 2020 Elsevier Ltd. All rights reserved.