Corrosion Deterioration of Reinforced Concrete in a Saline Soil Environment

Abstract

To mitigate issues pertaining to reinforced concrete damage under the action of various strong corrosive ions in saline soil areas, the corrosion characteristics of reinforced concrete are investigated via electrochemical tests [performed based on electrochemical impedance spectroscopy (EIS) and polarization curves] and chloride ion concentration tests, as well as based on the degree of concrete damage. The morphology and microstructure of the reinforced concrete are characterized via field emission scanning electron microscopy and X-ray photoelectron spectroscopy. Two deterioration indices, i.e., the reinforcement corrosion current and concrete damage degree, are selected to establish a deterioration model of reinforced concrete based on the Weibull distribution function and to conduct a competitive failure analysis. The results show that the degree of deterioration of reinforced concrete increases nonlinearly with time. A surface crack was first observed in a specimen with 3.0% mass loss rate (MLR). The surface crack of the specimen and the corrosion depth of the internal steel bars expanded from 0.02 to 0.27 mm and from 55 to 130 μm, respectively, when the MLR increased from 3.0% to 4.5%. Based on the results, the corrosion current density and concrete damage degree can be used as effective indices for evaluating deterioration in reinforced concrete, and the changes with time in saline soil environment are in accordance with the Weibull distribution function.