Two-dimensional numerical model and fast estimation method for calculating crevice corrosion of cross-sea bridges

Abstract

Crevice corrosion commonly occurs in cross-sea bridges when the coating is disbonded and a holiday appears because of construction defects or environmental influences. A two-dimensional numerical model is developed to predict the crevice corrosion rate as well as its time-varying laws considering the adsorption of chloride ion. The mass-transfer equations, current density equations, electric neutralization principle and conservation law of electric charge are all included in the numerical model. Some parameters which may influence the corrosion rate are analyzed in a parametric study. The results show that the tensile stress has significant impacts to the crevice corrosion rate while the effects from the crevice width, concentration of chloride ion and corrosion time are less obvious. Based on the results and discussion, an empirical formula is finally proposed for a fast estimation of the crevice corrosion rate for the durability design and performance evaluation of cross-sea bridges.