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The Hong Kong-Zhuhai-Macao Bridge adopts an integrated protection system of high-performance coatings and sacrificial anode cathodic protection to ensure a design service life of 120 years. This system was developed under the guidance of the Institute of Metal Research, Chinese Academy of Sciences, addressing the harsh marine environment with salinity levels up to 17.02 g/L and humidity around 80%.
Coating Technology: The outer walls are treated with SEBF melt-combined epoxy coatings (up to 120 mm thick), while the inner walls use SLF polymer composite coatings to block chloride ion penetration.
Sacrificial Anode Protection: Zinc-aluminum alloy sacrificial anodes are installed at the base of each steel pipe pile, providing preferential corrosion protection for the structure. Each pile measures 75 meters in length, with a total system weight of 96,000 tons.
Epoxy-Coated Rebar: High-performance epoxy-coated steel reinforcement enhances concrete density and reduces carbonation and sulfate crystallization corrosion.
Multiple Anti-Corrosion Strategy: The splash zone and underwater sections combine impressed current cathodic protection and coatings for extended durability.
The use of controlled rolling and cooling steel technology enhances strength, weldability, and corrosion resistance, extending the structure’s service life.
The protection scheme was validated through a 20-year exposure test in Zhanjiang Port, confirming long-term stability under deep-sea pressure and optimizing calcium and magnesium deposit behavior.
A real-time in-situ monitoring system continuously tracks the potential of steel pipe piles and coating integrity, enabling intelligent adjustment of cathodic protection current density through a centralized control platform.
