CORROSIVE BEHAVIOR OF THERMAL SPRAYED ZINC COATING UNDER ASPHALT CONCRETE COAT ON STEELBRIDGE DECK

Corrosion properties of thermal sprayed Zinc coating under asphalt concrete pavement coat were studied.A theoretic model was set up to explain the reason for the electrochemical corrosion of thermal sprayed Zinc coating to reduce the capability of asphalt concrete coat.Relationship between potential and immersion time for coating,and polarization properties of the coating were studied with an IM6ex electrochemical workstation.Corrosion products were studied with XRD.A great lot of ZnO and Zn5(CO3)2(OH)6 were found in the corrosion products,which could destroy the bond between bond coat and anticorrosive coat,and acted as the headstream of cracks,making pavement coat destroyed ahead of schedule under load.