Effects of Carbon Nanotube-Carbon Fiber Cementitious Conductive Anode for Cathodic Protection of Reinforced Concrete

Abstract

Abstract Carbon nanotube-carbon fiber/cement-based composites used as auxiliary anode for cathodic protection of reinforced concrete were explored in this paper. Cathodic protection was applied with impressed current and its efficiency was verified by corrosion potential, corrosion current, and AC impedance spectroscopy. Results showed that cement composites containing 0.4 wt. % carbon fiber and 0.5 wt. % carbon nanotubes exhibit the optimum electrical and mechanical properties. Effective protection on steel re-bars can be expected due to a sufficient negative potential shift by the applied electric current. Compared with a carbon fiber cementitious conductive anode system, a decrease of corrosion current of steel re-bars was observed for the carbon nanotube-carbon fiber cementitious conductive anode system. During cathodic protection, both capacitive loop radius of a Nyquist plot in the intermediate frequency region and the charge transfer resistance increased with time. A detailed mechanism analysis of the efficiency of cathodic protection using the carbon nanotube-carbon fiber cementitious conductive anode is also included.