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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    Elsevier

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    Kidlington, Oxford  United Kingdom  OX5 1GB
  • Authors:
    • Liang, H
    • Li, Li
    • Poor, N D
    • Sagues, Alberto A
  • Publication Date: 2003-1

Language

  • English

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