Effect of copper-coated carbon fiber on the electromechanical and chloride extraction properties of cement-based anode materials

This study addressed the critical issue of ionic erosion in reinforced concrete structures exposed to coastal environments by developing a novel conductive cementitious anode material for chloride extraction, thereby enhancing steel reinforcement protection. The research focused on the preparation of copper-coated carbon fiber (PDA-CF-Cu) utilizing polydopamine (PDA) as an intermediary, coupled with electrochemical deposition for surface metallization of carbon fibers (CF). A multifunctional new type of conductive cementitious anode material was prepared.The microstructure and elemental changes of CF and PDA-CF-Cu were investigated. The effects of CF and PDA-CF-Cu on the electrical conductivity, piezoresistance and chloride extraction properties of cement-based anode materials at different doses were also investigated.The microstructure showed that the material deposited on the CF surface was dominated by Cu with fewer copper oxides. The introduction of PDA significantly enhanced the adhesion of the metal coating to the CF surface, where the bond strength of PDA-CF-Cu increased by 17 times. The best quality of the plated layer was achieved at coating parameters of 1V - 1h. The electrical conductivity of PDA-CF-Cu increased by a factor of 26 compared to CF. The conductive mortar containing PDA-CF-Cu exhibited higher piezoresistive stability and sensitivity compared to CF conductive mortar. At 28 d, the conductivities of 0.2 wt%, 0.4 wt%, and 0.6 wt% doping increased by 653.64 %, 172.74 %, and 25.34 %, respectively. In addition, the PDA-CF-Cu conductive mortar exhibited better chloride extraction efficiency. The chloride extraction efficiency of PDA-CF-Cu conductive mortar exhibited enhancements of 8.63 % and 14.36 % for the respective fiber dosages of 0.2 wt% and 0.4 wt%.