Effect of corrosion on the tensile and fatigue performance of CFRP strand Sheet/Steel double strap joints

Abstract

The applications of carbon fiber reinforced polymers (CFRPs) to strengthen aging steel structures and bridges have recently gained a wide interest due to their ease of use, corrosion resistance, and high tensile strength. In this research, the effects of aggressive corrosion environment on the mechanical and fatigue properties of CFRP strand sheet/steel double strap joints with various bond length were investigated. The CFRPs consisted of small-diameter strands stitched together to form a sheet. Initially, the stiffness, ultimate tensile and bond strength of the specimens were evaluated using a quasi-static tensile protocol. Then, specimens were exposed to an accelerated corrosive environments for 24, 48 and 72 h and their quasi-static properties were analyzed. Furthermore, the specimens were subjected to fatigue loading with a frequency of 10 Hz and a stress ratio of 0.1. Finally, a fatigue model was developed based on the observed results. The experimental results revealed that the use of a relatively longer bond length reduced the corrosion rate and improved the fatigue performance of CFRP strand sheet/steel double strap specimens subjected to corrosive environments. However, specimens with a larger bond length did not have a significant effect on enhancing the stiffness and strength when subjected to accelerated corrosive environments up to 48 h. Specimens subjected to accelerated corrosive environments for 72 h had a significant increase in stiffness (∼14%) and strength (∼11%) with the increase of bond length.