Environmental impact on the durability of FRP reinforcing bars

Fiber reinforced polymer (FRP) bars are being widely used in civil engineering applications to replace steel bars due to their excellent durability. Existing research on the durability of FRP bars mainly focuses on glass fiber reinforced polymer (GFRP) and basalt fiber reinforced polymer (BFRP) bars. Different conclusions have been drawn due to differences in fibers, resins, fiber volume fractions, solution concentrations, and aging temperatures adopted by researchers. Some results are even contradictory, especially between relatively recent and previous studies. In this paper, data of 557 experiments on tensile strength and elastic modulus of GFRP and BFRP bars exposed to different harsh environments are collected from existing literature, and the durability of GFRP and BFRP bars in the water, acid, salt, and alkali solutions are investigated. Different influence factors are considered including the matrix type, fiber volume fraction and exposure temperature, etc. Furthermore, a new prediction model for the long-term performance of FRP bars is developed based on an existing model and the data collected in this paper. The tensile strength of GFRP and BFRP bars degenerates faster in alkali, and water environments, followed by acid solution, and has the best durability in salt solutions. Except the water solution, GFRP bars show better corrosion resistance than BFRP bars in alkali, salt, and acid solution. The new prediction is simple in form and clear in the physical meaning and can be considered for both GFRP and BFRP bars