2019 CSCE Annual Conference - Laval (Greater Montreal)

2019 CSCE Annual Conference - Laval (Greater Montreal) Conference

Severe Corrosion Behavior of Two-way Slabs under Different Accelerated Corrosion Techniques

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Mr. Mahmoud Said, Memorial University of Newfoundland (Presenter)
Dr. Amgad Hussein, Memorial University of Newfoundland
Mr. Nick Gillis, SNC Lavalin Inc, Canada

The behaviour of severe corrosion was illustrated in this paper using two different accelerated techniques. Each accelerated technique reached the same corrosion level, 50% mass loss. One technique used constant voltage and the other one used constant current. Two full-scale two-way slabs of dimensions 1900 mm × 1900 mm × 150 mm were cast for this purpose. A column stub with a cross-sectional area of 250 mm × 250 mm and a height of 200 mm was attached to each slab. The quality of concrete was examined before inducing the corrosion by doing a rapid chloride penetration test to ensure an acceptable concrete quality against chloride ingress. The corrosion behaviour for each slab was assessed based on the results of the current, half-cell potential, corrosion cracks pattern, natural frequency, chloride content, and mass loss. Both techniques showed a close agreement between the actual and the theoretical mass loss, which was calculated using Faraday’s equation. It was observed that the corrosion cracks in constant voltage technique were induced randomly while in the other slab induced above the corroded bar. This could be attributed to the current value that was kept constant in constant current technique, while the current value varied in the constant voltage technique and reached high values. This could increase the probability of a constant voltage technique to cause more damage than a constant current.