Abstract
The chemical, physical-chemical and electrochemical properties of a soil characterize its corrosivity, and external factors determine its relative aggressivity. Buried structures are subject to corrosion and the intensity of the process is related to the aggressivity of the soil. Several parameters such as resistivity, pH, water retention capacity and the presence of soluble salts are characteristics that indicate the corrosivity. In this work, several experimental techniques have been used to analyze soil samples collected in different regions of Rio de Janeiro, considering mountain and industrial features. The laboratory tests consisted of chemical, physical-chemical and electrochemical analysis, besides gravimetric testing. The tests were also carried out in full scale conditions. Qualitative and semi-quantitative analyses of the insoluble constituents were performed through X-Ray Fluorescence Spectroscopy (FRX) and the soluble constituents were evaluated quantitatively through aqueous extracts with FRX and the spectrophotometer. Concerning the physical-chemical parameters, the pH values, redox potential, resistivity vs humidity and water retention capacity were determined. In laboratory, coupons were exposed to soil samples with humidity between 5% and 30%. Corrosion potentials, polarization curves and corrosion rates were obtained in lab and full scale conditions. After 30 days of exposure, surface analyses were carried out to determine the morphology of the localized corrosion process.
