Electrochemical and characterisation study of corrosion of reinforcing steel embedded in kaolinite: two-year exposure study

ABSTRACT

Corrosion of reinforcing steel embedded in kaolinite clay was studied for a two year exposure period. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarisation (POL) revealed a decrease of the corrosion rate (CR) of the steel bars up to average values of 2.5 μm y⁻¹. X-ray photoelectron spectroscopy (XPS), and Scanning electron microscope (SEM) equipped with Energy-dispersive X-ray spectroscopy (EDX) techniques showed the formation of a thick and compacted corrosion layer composed of several iron oxides, namely, Fe₂O₃, Fe (OH)₂, Fe₃O₄ and FeCO₃. The external corrosion product is composed mainly of magnetite (Fe₃O₄) and siderite (FeCO₃). EDX mapping showed a homogeneous distribution of the elements across the cross-sectional of the corrosion layer.

KEYWORDS:

• Reinforcing steel
• XPS
• kaolinite
• corrosion rate
• corrosion product

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Acknowledgements

A special acknowledgment must be given to the members of the LOMC laboratory (University of Le Havre, France) for all support and assistance.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work is part of a PhD thesis and it’s financially supported by University of Science and Technology of Oran-Mohamed Boudiaf (Algeria).