ISSN: 0149-6123
Page Count: 11

The Passivation of Reinforcing Steel Exposed to Synthetic Pore Solution and the Effect of Calcium-Nitrite Inhibitor
Tullmin, M
Queen's University, Ontario

Mammoliti, L
Queen's University, Ontario

Sohdi, R
University of Toronto, Centre for Biomaterials, Ontario

Hansson, CM
Queen's University, Ontario

Hope, BB
Queen's University, Ontario

Abstract

Potentiodynamic polarization studies were conducted on rebar steel in a simulated cement paste pore solution containing sodium chloride, with and without additions of calcium-nitrite inhibitor. The rebar steel passivated spontaneously and displayed an extensive passive potential range in both cases. Surprisingly, however, passivity breakdown was observed to occur at a lower potential in the inhibited solution. XPS surface analysis indicated a similar composition of the passive films formed in the inhibited and uninhibited pore solutions. Only trace amounts of nitrogen were detected in the passive films. On the basis of the XPS results and the reported nitrite-inhibition mechanism, it would appear that the smaller passive potential range associated with the inhibitor additions is related to a decrease in pH recorded after the inhibitor addition.

Keywords:
reinforcing steel, passivation, calcium nitrite, chloride, pore solution

Paper ID: CCA10139J
DOI: 10.1520/CCA10139J
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