Brief introduction of Hong Kong-Zhuhai-Macao Bridge cathodic protection project

1. Technical solutions and objectives

The Hong Kong-Zhuhai-Macao Bridge has adopted the joint protection technology of "‌ high-performance coating + sacrificing-anode cathodal protection ‌" to ensure the design life of ‌120 years ‌ for the main structure in the highly corrosive environment of 17.02g/L‌ and 80% humidity in the Lingdingyang Sea area. The technology, led by the Institute of Metal Research of the Chinese Academy of Sciences, covers core parts such as steel pipe piles and concrete structures ‌.

2. Core protection measures

‌steel pipe pile double protection

·‌ coating technology ‌ : The outer wall of steel pipe piles is coated with ‌SEBF melt combined epoxy powder coating ‌ (thickness up to 120mm), and the inner wall is coated with ‌SLF polymer composite coating ‌ to block chloride ion penetration ‌.

·‌ sacrificial anode protection ‌ : A zinc-aluminum alloy sacrificial anode is installed at the bottom of the steel pipe pile to protect the pile through preferential corrosion. The single steel pipe pile is 75 meters long and weighs a total of 96,000 tons ‌.

concrete structure anticorrosion

·‌ epoxy-coated rebar ‌ : a new generation of high-performance epoxy-coated rebar is used to optimize the mix ratio and compactness of concrete to resist carbonization and sulfate crystallization corrosion ‌.

·‌ Multiple anti-corrosion strategy ‌ : high risk areas such as splash area and underwater area are combined with impressed current cathodic protection and coating technology to extend durability ‌.

3. Technological innovation and monitoring

Material and technology breakthrough ‌

steel strengthening ‌ : The use of a new generation of controlled rolling and controlled cooling process steel, improve strength and toughness and weldability, reduce carbon equivalent to extend the service life ‌3.

in situ monitoring system ‌ : real-time tracking steel pipe pile potential, coating integrity and other parameters, dynamic adjustment of cathodic protection current density ‌.

Adaptation to extreme environments ‌

The reliability of the protection scheme was verified by the 20-year exposure test in Zhanjiang Port, and the stability of calcium and magnesium deposits was optimized for deep-sea pressure ‌.