Appendix B - Corrosion Resistant Alloys for Reinforced Concrete
EXAMPLE CALCULATION OF CORROSION RATE FROM POLARIZATION RESISTANCE
Corrosion rate, CR, was calculated from the measured polarization resistance, PR, using a modified form of the Stern-Geary equation,
where Z is atomic weight, n is the number of electrical equivalents, F is Faraday’s constant, ρ is alloy density, and B is a term the value for which depends on the Tafel constants. For the case of black bar reinforcing steel, a typical measured value for PR was 103 Ω·cm2. Thus, with values for the other constants as,
| Z = 56 grams/mol, |
| n = 2 equivalents, |
| F = 96,500 Coulombs/mol·equivalent, |
| ρ = 7.87 grams/cm3, and |
| B = 0.026 V, |
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