Marine and Port Engineering-Holy Hong Chemical (Dalian) Co., Ltd.

Long-term Anti-corrosion Engineering Testing for Cross-Sea Bridges

China—East China Sea海域

2023

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Facing challenges

This cross-sea bridge is located in a marine environment characterized by high salt mist and high humidity, and is subjected to constant splashing from sea waves and intense ultraviolet radiation. Traditional oil-based coatings are significantly affected by humidity during application, and their VOC emissions struggle to meet the region’s stringent environmental protection requirements. The customer requires the coating system to meet the 25-year long-term protective standard under C5-M corrosive conditions.

Solution

The system employs a coordinated coating scheme consisting of “waterborne inorganic zinc-rich primer + waterborne epoxy micaceous iron intermediate coat + waterborne polyurethane topcoat.” The primer provides robust cathodic protection; the intermediate coat enhances barrier properties and interlayer adhesion; and the topcoat boasts exceptional weather resistance and self-cleaning capabilities, effectively resisting UV radiation and salt spray corrosion. This all-waterborne system is safe and environmentally friendly to apply, and is unaffected by high-humidity environments.

Project outcomes

After the project was completed, all tested coating performance indicators exceeded the design requirements. Following a year of actual operation, the coating surface remained as bright and new as ever, with no signs of chalking, blistering, or rusting. This project has become a benchmark case for local green anti-corrosion engineering.

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