With the development of high-speed and electrified railways, the requirements for steel bridge maintenance and overhaul are higher. It is impossible to carry out construction operations on bridges as before. This requires the development of coatings with better corrosion resistance and longer service life. The system only applies one or two times of protection coating during the whole process of steel bridge use, and at the same time, it should develop water-based paints and environmentally-friendly paints with low environmental pollution.
1 high performance coating
Such as room temperature curing fluorocarbon coating, it has extraordinary weather resistance, outstanding salt spray resistance, excellent chemical resistance and good stain resistance and erosion resistance. Domestic fluorocarbon coatings still have a certain gap with foreign products in terms of main performance. Therefore, research and development of fluorocarbon coatings, especially fluorocarbon resins, should be strengthened to produce fluorocarbon coatings in the true sense.
2 water-based paint
With the continuous improvement of living standards, people's awareness of environmental protection is also increasing, and the use of water-based paints for steel bridge painting is an inevitable trend. As a pre-coating primer, water-based inorganic zinc-rich paint has been widely used in steel structure processing in China. It has also been used as a matching primer on steel bridges in China, but there are still some problems in use, such as brittle coating, and other Coatings are not well matched, and further improvements and research are needed.
3 composite protection material
The steel bridge surface is arc-sprayed with metal and then topcoated. Spray metal protection began in 1910 and has a history of more than 90 years. In the 1930s, foreign countries have widely used zinc-spray coating and then sprayed aluminum coating to protect railways and highway bridges, various hydraulic steel structures and hydropower equipment, petrochemical equipment and ships. China has been applied since the 1950s and has a history of 50 years. Practice has proved that spray metal corrosion protection is a long-lasting and applicable anti-corrosion method. After more than 90 years of development, the metal spray can not only spray zinc, spray aluminum but also spray aluminum alloy, spray aluminum-magnesium alloy and spray aluminum rare earth alloy; in the spraying process, it also gradually develops from flame spraying to arc spraying or even high-speed arc spraying. Wait. Arc-sprayed metal lacquer finishes have been applied in China's port terminals and bridges in recent years, such as the Yuehai Trestle Bridge Project.
4 Protective materials for railway reinforced concrete bridges
At present, the design life of railway reinforced concrete bridges is the same as that of steel bridges. It is 100 years. In addition, the concrete bridges on the existing lines also have various degrees of corrosion and other damage. Therefore, it needs to be repaired or protected. One of the main protective measures is to develop protective coatings and develop corresponding construction techniques.
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