Experimental study on bond behavior between wet lay-up CFRP and corroded steel plates

Abstract

Corrosion of steel in marine environments is a major safety concern for marine steel structures throughout their service lives. Strengthening these corrosion-damaged structures with carbon fiber-reinforced polymer (CFRP) shows great potential for extending their service lives. However, the bond behavior between CFRP and corroded steel, especially the influence from adhesive properties and corrosion degree, has not been fully understood. This paper therefore presents the results of a comprehensive experimental study on the bond behavior between wet lay-up CFRP and corroded Q355B steel plates. Tensile tests on double-lap CFRP-to-steel joint specimens with different bonded lengths, adhesives and corrosion durations were then conducted. The failure modes, load-displacement curves, strain and local shear stress distributions, effective bond lengths, and bond-slip relationships of the test joint specimens were investigated in detail. The result showed that the influence of corrosion on the CFRP-to-steel bond performance varied depending on the failure modes resulting from the material properties of adhesives. However, corrosion has insignificant influence on the general patterns of load-displacement curves, strain distribution, local shear stress distribution, local bond-slip curves with same adhesives. When failure occurred in the adhesive or the steel-adhesive interface, the corrosion tended to have a more accentuated effect on the bond performance.