Influence of chloride ion on depassivation of passive film on galvanized steel bars in concrete pore solution

Haibing Zheng, Jianguo Dai, Weihua Li, Chi Sun Poon

Research output: Journal article publicationJournal articleAcademic researchpeer-review

14 Citations (Scopus)

Abstract

This work aimed at studying the depassivation mechanism of the passive film on galvanized steel bar in concrete pore solution with different concentrations of chloride ion. The results showed that in a saturated Ca(OH) 2 solution, the critical chloride values for the depassivation of the passive films formed on galvanized steel bars and zinc metal specimens were 0.2 M and 0.3 M respectively. When the Cl concentration was lower than the critical value, the donor density of the passive film increased and thus the protective property reduced with increasing the concentration of chloride ion, which could be interpreted by the point defect model (PDM). The corrosion products formed on the galvanized steel surface could inhibit the further ingress of the chloride ions and enhance the protective property, while such effect was not obvious for the zinc metal.

Original languageEnglish
Pages (from-to)572-580
Number of pages9
JournalConstruction and Building Materials
Volume166
DOIs
Publication statusPublished - 30 Mar 2018

Keywords

  • Chloride ions
  • Concrete pore solution
  • Corrosion
  • Galvanized steel
  • Passive film

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Materials Science(all)

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