| The corrosion and protection of steel pipe pile in the marine environment is one of the hot spots in the current research.From the published literature,researchers usually use different marine environment to study the corrosion behavior of steel pipe pile materials in the single corrosion zone,while the research on the corrosion and protection of materials in the cross corrosion zone considering th e continuous long-scale effect of the simulated pile length direction is less.In the actual Shanghai ocean environment,steel pipe piles are located in different corrosion areas,so it is difficult to accurately simulate the actual situation of the project by the research method of single hanging piece.At the same time,in order to determine the test plan of the steel pipe pile field exposure test station to be built in the East China Sea.In this paper,the simulated corrosion tests of short and long-scale specimens in tidal range and full immersion zone were carried out in laboratory under different anti-corrosion measures.A series of studies were carried out using electrochemical corrosion measurement technology,and the following results were obtained:(1)The open circuit potential test results of the samples in the tidal range area show that the potential of the short scale sample is lower than that of the long scale sample in the tidal range area without anti-corrosion measures,with anti-corrosion measures for welds and epoxy powder coating,in which the potential of the epoxy powder coating is higher and more stable,the open circuit potential of the short scale sample is about-0.64 V,and the potential of the long scale sample is about-0.58 V.(2)The results show that the open circuit potential of the sample without anticorrosive measures is higher than that of the sample without anticorrosive measures,but the potential difference is smaller.Compared with the short-scale and long-scale samples with other anticorrosive measures,the potential of epoxy powder coating samples is higher and more stable,indicating that the corrosion tendency of the samples with epoxy powder coating is smaller.(3)The polarization curve test results of the samples in the tidal range show that the corrosion rate of the short scale samples under different corrosion protection measures is higher than that of the long scale samples.The comparison of different corrosion protection measures shows that the minimum corrosion rate of the samples with epoxy powder coating corrosion protection measures is about 0.0002mm/a,which is 3 times smaller than that of the samples without corrosion protection measures,It shows good corrosion resistance.(4)The polarization curve test results show that the corrosion rate of short-scale specimen is lower than that of long-scale specimen under different corrosion protection measures,and the corrosion rate of the specimen with epoxy powder coating is still the lowest,showing the corrosion resistance of the epoxy powder coating.The little difference between the corrosion rate of the samples with weld but without anti-corrosion measures or without corrosion protection measures,which proves that the proper treatment of the weld will not have a great impact on the corrosion.(5)The polarization curve data analysis shows that the corrosion rate of the long-scale specimen in the tidal zone and the full immersion zone is different from that of the short-scale specimen,and the corrosion rate of the long-scale specimen in the tidal zone tends to decrease,while the corrosion rate of the long-scale specimen in the full immersion zone tends to increase,which proves that the corrosion rate of the long-scale specimen in the cross corrosion zone changes.It is suggested that in the long-term exposure test of steel pipe piles in the East China Sea,the long-scale effect should be taken into account in the test plan,and full-scale samples should be set up across the corrosion area to ensure that the corrosion situation in the actual project can be reflected more accurately. |
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