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Chloride corrosion threshold of reinforcing steel in alkaline solutions - Cyclic polarization behavior
Cyclic polarization (CYP) experiments were performed on reinforcing steel bars of various surface finishes in chloride-containing alkaline solutions (pH 11.6 -13.6). Pitting initiation was observed at potentials below the oxygen evolution potential (EOE) when the solution [Cl(-)]/[OH(-)] ratio (CR) was high enough. The pitting potential (Ep) was not a unique function of a given test condition. Both the average value and the variability of Ep tended to decrease with increasing CR. Increasing passive film maturity and steel surface smoothness effectively elevated Ep values. The repassivation potential (Er) also showed certain variability, but it was insensitive to steel surface conditions and solution compositions. Erwas instead a strong function of the severity of corrosion attack (represented by imax)that had occurred on the steel surface before repassivation. The experimental results were examined using a statistical approach. Based on simplifying assumptions, the chloride corrosion threshold (CRT) was estimated from the CYP results as a function of the testing parameters. The estimated CRT values increased with solution pH, a trend that agreed with earlier results from long-term open-circuit immersion (OCI) tests. The stochastic character of Ep needs to be considered when applying test results from small-sized laboratory specimens to the problem of corrosion initiation in a large structure.
Chloride corrosion threshold of reinforcing steel in alkaline solutions - Cyclic polarization behavior
Cyclic polarization (CYP) experiments were performed on reinforcing steel bars of various surface finishes in chloride-containing alkaline solutions (pH 11.6 -13.6). Pitting initiation was observed at potentials below the oxygen evolution potential (EOE) when the solution [Cl(-)]/[OH(-)] ratio (CR) was high enough. The pitting potential (Ep) was not a unique function of a given test condition. Both the average value and the variability of Ep tended to decrease with increasing CR. Increasing passive film maturity and steel surface smoothness effectively elevated Ep values. The repassivation potential (Er) also showed certain variability, but it was insensitive to steel surface conditions and solution compositions. Erwas instead a strong function of the severity of corrosion attack (represented by imax)that had occurred on the steel surface before repassivation. The experimental results were examined using a statistical approach. Based on simplifying assumptions, the chloride corrosion threshold (CRT) was estimated from the CYP results as a function of the testing parameters. The estimated CRT values increased with solution pH, a trend that agreed with earlier results from long-term open-circuit immersion (OCI) tests. The stochastic character of Ep needs to be considered when applying test results from small-sized laboratory specimens to the problem of corrosion initiation in a large structure.
Chloride corrosion threshold of reinforcing steel in alkaline solutions - Cyclic polarization behavior
Grenzwert der Chloridkorrosion von Bewehrungsstahl in alkalischen Lösungen: Zyklisches Polarisationsverhalten
Li, L. (author) / Sagües, A.A. (author)
Corrosion, Houston ; 58 ; 305-316
2002
12 Seiten, 20 Bilder, 4 Tabellen, 29 Quellen
Article (Journal)
English
Chloride Corrosion Threshold of Reinforcing Steel in Alkaline Solutions-Cyclic Polarization Behavior
| British Library Online Contents | 2002
Chloride Corrosion Threshold of Reinforcing Steel in Alkaline Solutions-Effect of Specimen Size
| British Library Online Contents | 2004
Chloride Corrosion Threshold of Reinforcing Steel in Alkaline Solutions-Open-Circuit Immersion Tests
| British Library Online Contents | 2001