NITRITE DIFFUSIVITY IN CALCIUM NITRITE-ADMIXED HARDENED CONCRETE

When present in concrete, nitrite significantly increases the critical chloride threshold for corrosion initiation. This article reports on a study in which the apparent diffusivities (D sub-app) of nitrite in concrete were estimated by monitoring time-dependent concentrations of nitrite leached into water from calcium nitrite-admixed hardened concrete specimens. The authors conducted experiments with five different concrete mixes and with deionized water (DI), limewater, or synthetic seawater as the leaching agents. Results showed that the D sub-app was relatively insensitive to nitrite dosage and to DI or limewater as the leaching agent, but an increase in the w/c ratio to 0.49, or an increase in temperature by approximately 14 deg C, increased D sub-app by approximately 50%. The effect of seawater needs further investigation. A 20% Type F fly ash cement replacement reduced the apparent diffusivity by approximately 60%. Extended curing of the concrete significantly reduced D sub-app. The magnitude of the D sub-app and its dependence on concrete and exposure parameters were comparable to those observed in the transport of chloride ions in concrete.

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• Corporate Authors:

  Elsevier

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• Authors:
  • Liang, H
  • Li, Li
  • Poor, N D
  • Sagues, Alberto A
• Publication Date: 2003-1

Language

• English

Media Info

• Features: Appendices; Figures; References; Tables;
• Pagination: p. 139-146
• Serial:
  • Cement and Concrete Research
  • Volume: 33
  • Issue Number: 1
  • Publisher: Elsevier
  • ISSN: 0008-8846
  • Serial URL: http://www.sciencedirect.com/science/journal/00088846

Subject/Index Terms

• TRT Terms: Admixtures; Chlorides; Concrete; Corrosion; Diffusivity; Fly ash; Hydration; Nitrites; Pozzolanic action
• Subject Areas: Highways; Materials; I32: Concrete;

Filing Info

• Accession Number: 00986469
• Record Type: Publication
• Files: TRIS
• Created Date: Feb 8 2005 12:00AM