Abstract
For the purpose of investigating the corrosion rate and cathodic protection effect of the harbour steel structures in Japan, about 400 mild steel test pieces were immersed in sea water and a half of them were electrically connected to 47 cathodically protected steel sheet pile quay walls or steel pipe pile jetties in various harboures over the period from three months to six years. From the test results, it was proven that the mean corrosion rate of nonprotected mild steel below the low water level was 0.13mm per year, the ratio of maximum and minimum corrosion rates being more than ten times, and the mean corrosion rate of cathodically protected pieces was 0.012mm per year, indicating the protection rate of 91%. The influence of polluted sea water on corrosion of steel could not be elucidated.
