In situ 3D monitoring of corrosion on carbon steel and ferritic stainless steel embedded in cement paste

• The morphology of the corrosion of steel in cement paste was studied in situ.
• During galvanostatic corrosion, carbon steel reinforcement corroded homogeneously.
• On ferritic stainless steel, deep corrosion pits formed and caused wider cracks.
• The measured rate of steel loss correlated well with Faraday’s law of electrolysis.

In a X-ray microcomputed tomography study, active corrosion was induced by galvanostatically corroding steel embedded in cement paste. The results give insight into corrosion product build up, crack formation, leaching of products into the cracks and voids, and differences in morphology of corrosion attack in the case of carbon steel or stainless steel reinforcement. Carbon steel was homogeneously etched away with a homogeneous layer of corrosion products forming at the steel/cement paste interface. For ferritic stainless steel, pits were forming, concentrating the corrosion products locally, which led to more extensive damage on the cement paste cover.

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