Electrolytic measurement of the corrosiveness of soils

Abstract

The electrolytic behavior of steel in contact with 47 soils of known corrosiveness was studied by means of a cell in which both electrodes were steel and the electrolyte was moist soil. By providing differential aeration of the electrodes the cell was enabled to develop its own electromotive force. Measurements were made of the voltage, current, and resistance of such cells. The relation between the current density and applied voltage was also studied. The losses in weight of the test specimens were related to the average current density over a certain range of applied voltage and to the total quantity of electricity produced in the corrosion process. The corrosion of the specimens in the laboratory t ests was correlated with corrosion experienced in long-time field tests. The results of the tests may be applied practically in predicting the corrosiveness of soils toward iron and steel. However, they cannot be applied to the prediction of leaks or to the estimation of the useful life of a section of pipe line until the relations connected depth of pitting with exposed area and time can be established.