The corrosive media in the environment, such as water, gas and salt, can enter into the concrete through infiltration and diffusion, causing corrosion and deterioration of the concrete and corrosion of the steel reinforcement.

In accordance with the steel viaduct is in a relatively severe industrial and marine atmospheric corrosive environment with a service life of 100 years, the design of the anti-corrosion coating programme requires a protection life of more than 50 years.