Transverse low-velocity impact performance of BFRP bars after exposure to the saline-alkaline environment

Abstract

The saline environment is one of the most severe exposure conditions for infrastructure due to its corrosive nature. Fiber reinforcement polymer (FRP) bars are being considered as a replacement for steel rebars to prevent corrosion. However, the effects of saline environments and alkaline cementitious conditions on the impact performance of FRP bars are not well known. Therefore, this study aims at examining the low-velocity impact performance of basalt FRP (BFRP) bars after exposure to the saline-alkaline environment for 24, 48, and 72 days and elevated temperatures (25, 40, and 55 °C). The maximum load-bearing capacity, deformation capacity, and energy absorption capacity of the deteriorated BFRP bars are measured. Environmental scanning electron microscope (ESEM) and Fourier transform infrared spectroscopy (FTIR) were used to study the deterioration mechanism further. It was revealed that both the fracture threshold and the bending stiffness of BFRP bars generally decrease with the elevated exposure temperature and duration. The findings also suggest that deterioration of BFRP bars in a natural saline-alkaline environment is less severe than the simulated saline-alkaline solution. This study provides some insights to promote the application of FRP composites in coastal and marine structures in a saline-alkaline environment with low-velocity impact loads.