Volume 6, Issue 2 (June 1983)
Measurement of Underground Corrosion of Steel
Underground corrosion of steel was studied from a measurement of the soil resistance and the degree of soil depolarization. This technique is capable of giving an instantaneous corrosion rate of steel in soil. A cell consisting of magnesium and steel as electrodes with the soil in between them was used as a probe. The current passing between the electrodes is chiefly controlled by the degree of soil depolarization. A resistance bridge operating on an alternating current determines the pure resistance between the electrodes. Various soils were studied with the instrument. Organic soils were found to be highly corrosive (corrosion rate of as high as 0.096 mm/year). Since the corrosion rate varies considerably for different types of soils, the soil resistance and degree of depolarization measurements could be useful in soil profiling.