Electrochemical impedance behavior of mortar subjected to a sulfate environment – A comparison with chloride exposure models

• Published in: Construction & building materials 2014-10, Vol.68, p.650-658
• Main Authors: Bragança, Mariana O.G.P., Portella, Kleber F., Bonato, Marcelle M., Marino, Cláudia E.B.
• Format: Article
• Language: English
• Subjects: Analysis; Chemical properties; Durability; Electrochemical impedance spectroscopy; External sulfate attack; Mortar; Non-destructive diagnosis; Non-destructive testing; Sulfates
• ISSN: 0950-0618
• DOI: 10.1016/j.conbuildmat.2014.06.040

•Sulfate attack in mortar was studied by electrochemical impedance spectroscopy.•Mechanisms that occur under the mortar pores during the aging were highlighted.•Mortar resistance shifted and the system presented a capacitive behavior.•Electrochemical impedance identified the sulfate attack by non-destructive method.•Electrochemical results were comparable with physical chemical characterizations. Samples of reinforced mortar specimens (Sps) were studied over 300days of exposure in reference, sulfate, and chloride environments. Electrochemical impedance spectroscopy (EIS) was used to investigate external sulfate attack (ESA) in comparison with known chloride models. The study, based on the mortar behavior and its measured electrical properties, highlighted the mechanisms that occur under the pores during the aging. The sulfate samples presented a capacitive behavior at lower frequencies, and the mortar resistance shifted. It was confirmed that EIS is a qualified technique to identify the sulfate attack in concrete by non-destructive methods.