Research On Long-term Corrosion Protection Of Bridge Cables Based On OTC Technology

With the rapid development of China's economy and the increasing mature transportation engineering technology,and in order to promote the connectivity of coastal cities,the construction and development of ocean long-span cable Bridges will have a broad prospect in the future.However,there is a great threat to the cable bridge due to the harsh atmosphere.At present,the design life of cable bridge is generally more than 50 years,but in fact,the average life of cable bridge in China is only about 10 years,and the biggest problem for the cable is corrosion.The designers of Bridges mostly pay attention to structural problems such as load-bearing in their design,however,pay relatively little attention to corrosion problems.As a result,cable Bridges often meet the load-bearing requirements in the initial design and construction,but with the occurrence of corrosion,the mechanical properties of cables decline,will develop a corrosion crisis.There have been many serious accidents of broken cables and even broken Bridges in China.Corrosion has restricted the development of cable Bridges.This paper takes the long-term protection of bridge cables as the research topic,and the main contents include the following aspects:(1)Firstly,this paper studies the structure of cable bridge,cable production technology and corrosion hazards of cable.(2)According to the Marine and atmospheric environment of the bridge cable,introduce the corrosion characteristics,formation mechanism,and introduce several methods of atmospheric corrosion test and analysis method,and the corrosion behavior of steel wires,and the structure composition,technical advantages of OTC(oxidation polymerization coating technology)and its protection examples in other fields are also introduced.(3)The corrosion behavior of the steel wire in the damaged state and Cable stock form was studied experimenntally.Experiments show that the weight loss of OTC protection of non-galvanized steel wire under damage condition is significantly lower than that of reference sample and seal protection,and the corrosion rate is reduced by 84.4%.The morphology after corrosion shows that the shape of the corrosion pit under OTC protection is obviously different from the other two types.The corrosion principle and the growth mode of corrosion pit are different.and the pit develop along the surface of the steel wire witch the depth is almost constant,and the corrosion has a tendency of local corrosion to uiform corrosion.The salt spray test in the form of the cable stock simulates the structural form of the bridge cable and is more realistic.The tests show that the sealed steel wire in the form of the cable stock is slightly different from the unprotected reference steel wire,mainly reflecting the accumulation of corrosion products on the reference steel wire in the initial stage of corrosion,so that the total impedance is increased.The corrosion products under the OTC coating are less,and the formation of the micelle covering and the steel wire surface protection wire does not continue to be corroded.The electrochemical tests show that the OTC corrosion resistance is large and the corrosion current density is small.(4)This paper summarizes the protection system and methods of bridge cables and proposes to apply OTC technology as an active protection method to bridge cable protection.As a new anti-corrosion method of technology,long-term,active and green,OTC can greatly reduce the maintenance cost of cables and increase the service life of cables.