Abstract:
Epoxy coated reinforcement is one of the anti-corrosion measures for reinforced concrete. Due to the insulation characteristics of epoxy coating, electrochemical protection measures can not be used in the later maintenance of reinforced concrete structure, but this problem may be solved by using conductive anti-corrosion coating on the surface of reinforcement.
Graphene
has special properties of conductivity, corrosion resistance and impact resistance. In this paper, a conductive anticorrosive coating composed of water-based epoxy resin, graphene and other conductive fillers is studied. The shape of the conductive filler and the structure of the coating are characterized by electron microscope. The acting mechanisms of conductive and anticorrosive of the coating are analyzed, and the adhesion strength to concrete of the conductive coated reinforcement is tested. The results show that the conductivity of the coating can be less than the square resistance value of 3000 Ω/sq. The coating is alkali resistant while soaked in alkaline solution, and the coating does not blister or rust for more than 21 days in alkaline solution containing Cl
−, and does not blister for more than 21 days and does not rust for 14 days in Cl
− solution. The coating must be obtained by mixing different conductive fillers including graphene. The conductive mechanism may be that conducts electricity is obtained through the mutual contact among film graphene, flake graphite and spherical carbon black particles. The corrosion resistance of the coating is improved by using the film characteristics of graphene to extend the permeability channel of the medium. The bond strength of coated steel to concrete is about 15% lower than that of uncoated steel, and the result meets the requirements of national standard GB/T 25826—2010.
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