The hottest joint protection technology guards the

2022-08-20
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Joint protection technology protects the Hong Kong Zhuhai Macao Bridge. China develops new coatings to challenge the 120 year durability of the Hong Kong Zhuhai Macao Bridge. China develops new coatings to challenge the 120 year durability of the Hong Kong Zhuhai Macao Bridge. November 5, 2018

the Hong Kong Zhuhai Macao Bridge, which has attracted the attention of the public, was officially opened recently. The design standard of the world's longest sea crossing bridge broke the usual "hundred year practice" in China and formulated a 120 year design standard. Behind it is a key technology for escort, which is the joint protective technology Chinese paint independently developed by the Institute of metals of the Chinese Academy of Sciences (referred to as the Institute of metals of the Chinese Academy of Sciences)

Li Jing, head of the durability protection and engineering research group of the Institute of metals, Chinese Academy of Sciences, told the economy - China's economy: "We have completed the protective coating process design, cathodic protection system design and in-situ corrosion monitoring system design of steel pipe composite piles for the foundation of Hong Kong Zhuhai Macao Bridge, developed a new generation of high-performance epoxy coated reinforcement for the concrete structure of the bridge, and participated in the anti-corrosion coating construction of the bridge foundation, ensuring the 120 year durability design requirements of the bridge foundation."

seawater impact corrosion is a direct challenge to the sea crossing bridge. In view of the specific sea mud environment of the Hong Kong Zhuhai Macao Bridge, during the demonstration of the bridge, the research group carried out the research and development of relevant coatings, exempted the consumption tax on lithium-ion batteries, solar cells, fuel cells, etc., and successively developed new coatings from the key performance indicators of the coating, such as permeability resistance, cathodic stripping resistance, etc., to solve the problem of the durability of the coating. By adjusting the coating formula and improving the coating process, the researchers reduced the water absorption and dissolution rate of the coating, effectively improved the impermeability of the coating, and enhanced the coherency load test of the coating and metal in an empty laboratory

the durability design requirement of 120 years is far from being achieved by only relying on the protective means of coating corrosion prevention, which must be combined with cathodic protection technology. Cathodic protection technology refers to the polarization of the metal structure to be protected through electrochemical methods, so that the potential moves to the negative direction, reaching the corrosion-free potential, so that the metal structure is in a protected state

it is reported that in the past, the focus of cathodic protection of sea crossing bridges in China was steel pipe piles immersed in seawater, while most steel pipe composite piles of Hong Kong Zhuhai Macao Bridge are located in the sea mud under the concrete cushion cap. There is no precedent for how to implement cathodic protection. According to the corrosive environment and structural characteristics, the researchers of the Institute of metals of the Chinese Academy of Sciences focused on the problems faced by the cathodic protection of steel pipe composite piles after pouring into different geological layers, and adopted ingenious methods to select extreme boundary parameters to calculate the protection effect, that is, to calculate the electric time of cathodic protection under the two conditions of maximum and minimum soil resistivity: whether the resin material level in the barrel can be completely removed to meet the protection requirements, As a means of cathodic protection design in similar projects, it effectively solves the problem of cathodic protection design in complex environment

in order to verify the feasibility of cathodic protection design of steel pipe composite piles, researchers carried out simulation experiments at the ratio of 1:20, and simulated the geological environment of steel pipe composite piles crossing Hong Kong Zhuhai Macao Bridge as far as possible. The scale model experiment proves that the design calculation method is correct and feasible. Then the 1 ∶ 1 full-scale structural test is carried out on the Hong Kong Zhuhai Macao Bridge. The results show that the new cathodic protection method can meet the protection requirements of the bridge foundation

after the simulation experiment, the researchers adopted the method of installing protective facilities monitoring probe on the inner wall of the steel pipe, and carried out in-situ monitoring with the probe under the sea mud of nearly 100 meters, which effectively solved the problem of installing detection equipment under the sea mud. It is the first time in the global ocean engineering community to install detection equipment in this way

the concrete used for the foundation pier of Hong Kong Zhuhai Macao Bridge is marine concrete. In addition to meeting the design and construction requirements, it has higher requirements in terms of impermeability, corrosion resistance, reinforcement corrosion prevention and construction impact resistance. To this end, researchers from the Institute of metals of the Chinese Academy of sciences have developed a high-performance coated steel bar technology. Experts believe that its technical performance exceeds the existing technical indicators of coated steel bars at home and abroad, and is at the international leading level among similar products, which can meet the engineering needs of Hong Kong Zhuhai Macao Bridge

the R & D and application of these protection technologies have enabled the Hong Kong Zhuhai Macao Bridge to achieve the 120 year design standard. (economy - China economy sun Qiantong, correspondent Feng Feng)

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