Study on Corrosion Characteristics of Concrete-Filled CFRP-Steel Tube Piles under Hygrothermal Environment

The corrosion damage of pile foundations caused by a hygrothermal environment is a significant factor that influences the service life of high-pile wharf structures. The concrete-filled CFRP-steel tube (CFRP-CFST) pile is a composite structure composed of external Carbon Fiber-Reinforced Polymer (CFRP) sheets and inner concrete-filled steel tubes. It has a high-bearing capacity and excellent corrosion resistance and is an ideal structure for pile foundations in aggressive environments. In this paper, twelve CFRP-CFST pile specimens with diameters of 114 mm and heights of 1200 mm and another forty-two CFRP-steel plate specimens with CFRP widths of 30-50 mm were built. A high hot and humid environment simulation system was designed to conduct corrosion experiments with these specimens. At different theoretical corrosion degrees, the half-cell potential, corrosion products, corrosion expansion, and adhesive property were investigated. The test results showed an obvious increase in the mechanical properties and corrosion resistance when the concrete-filled steel tube was externally bonded to CFRP sheets. The experimental results show that the CFRP-CFST pile is an effective way to protect piles from corrosion and can be widely used for high-pile wharfs in aggressive environments.