Life Prediction for Anticorrosive Coatings on Steel Bridges

Abstract

This paper presents the results of the effects of tensile stress and corrosion environment on the performances of epoxy (EP) coating systems and fluorocarbon (FC) coating systems on steel bridge by accelerated exposure test. Gloss, color characteristic parameter, and blistering area were selected to be aging indexes of anticorrosive coatings. Four different stress levels were applied on coated steel panel specimens by using a three-point bend loading, and the stress coefficient is proposed in this paper. The results showed that coating corroded more severely in seawater than in freshwater. The tensile stress may accelerate the degradation of the coating. The degree of corrosion damage of the coatings increased with the increase of stress levels. Natural exposure tests of EP and FC coating systems were performed at Sanya test site and Qingdao test site in China, respectively. The correlation between natural exposure test and accelerated exposure test is presented by the acceleration coefficient. A life prediction model of anticorrosive coatings on steel bridge is proposed. The stress coefficient was presented in the life prediction model. The stress coefficient increases with the increase of stress applied on coatings. The proposed life prediction model can provide an important basis for quantitatively describing the failure of anticorrosive coatings and predicting the life of anticorrosive coatings on steel bridges.