Erosion characteristics of viscoelastic anticorrosive coatings for steel structures under sand flow

Abstract Due to the continuous erosion of anticorrosive coatings on hydraulic steel structures, the coating falls off over large areas, causing exposure and rusting of the steel structure. This process directly affects the normal use of hydraulic steel structures. To study the erosion law of viscoelastic anticorrosive coatings for steel structures in a sand flow environment, three kinds of polyurethane coatings were prepared with different proportions (A:B = 1:1, 1:2 and 1:3), and accelerated physical erosion tests of the above-mentioned anticorrosive coatings for steel structures in a sand flow environment were carried out with traditional epoxy asphalt coatings as the control group. The erosion patterns of various viscoelastic anticorrosive coatings under different erosion times, sand flow velocity and sediment concentrations under sand flow were obtained. The results show that the abrasion amount of coatings is logarithmically correlated with erosion time and exponentially correlated with sand flow velocity. Under higher sediment concentrations (4.0–8.0 kg/m3), the abrasion of the coating increases with increasing sand flow velocity. Under an erosion condition of low sediment concentration (0.5–1.8 kg/m3), the abrasion of the coating undergoes a long period of slow growth. The abrasion of the polyurethane coating is lower than that of the epoxy asphalt coating, and among the tested samples, the 1:3 polyurethane coating has the least abrasion and the best erosion resistance. Based on the results of the accelerated erosion test and the existing erosion theory, a prediction model was proposed for the viscoelastic anticorrosive coating of steel structures under sand flow, and the correctness of the prediction model was verified by the experimental results. The research results have important guiding significance for reasonably predicting the durability of hydraulic steel structures.