FACTORS CONTROLLING CORROSION OF STEEL-REINFORCED CONCRETE SUBSTRUCTURE IN SEAWATER. FINAL REPORT

Laboratory experiments and computer model calculations were performed to assess the effect of critical design variables and concrete properties on the distribution of corrosion in reinforced concrete marine bridge substructures. Instrumented laboratory test columns were exposed for a period of three years in conditions simulating field service. One set of columns was made with concrete containing fly ash, concrete with fly ash plus silica fume, and concrete with either silane or siloxane surface treatments. This set was prepared for evaluation of the effects of concrete composition and surface treatments on corrosion distribution. From concrete resistivity measurements, the concrete with fly ash plus silica fume showed evidence of having the lowest permeability at early test ages (first two years), but the differences between both types of concrete tended to be less near the end of the test. Both surface treatments tended to reduce the intake of water but did not cause excessive water retention. Another set of columns was made with concrete without pozzolanic additions, and used to evaluate the effect of partial and saturating moisture application in the region above the waterline. Corrosion macrocell measurements indicated that cathodic activity (and macrocell action) increased with partial moisture application but reaches a limiting amount upon saturation. The behavior was linked to diffusional transport limitation of the oxygen reduction reaction. The computer calculations produced a comprehensive model to predict corrosion current distribution. The predicted corrosion was greatest at the top of the active steel zone in the reinforcement assembly. The calculations indicated that the diffusivity of oxygen in the concrete was relatively more important than concrete resistivity in determining the overall extent of corrosion. Applications of the findings to design of future structures are proposed.

  • Corporate Authors:

    University of South Florida, Tampa

    Department of Civil and Environmental Engineering, 4202 East Fowler Avenue
    Tampa, FL  United States  33620

    Florida Department of Transportation

    P.O. Box 1029
    Gainesville, FL  United States  32602

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Sagues, Alberto A
    • Kranc, S C
    • Al-Mansur, AKM
    • Hierholzer, S
  • Publication Date: 1994-12

Language

  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 115 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00672595
  • Record Type: Publication
  • Report/Paper Numbers: FL/DOT/RC/0537-3523, WPI 0510537, State Job 99700-7530-119
  • Files: TRIS, USDOT, STATEDOT
  • Created Date: Jan 20 1995 12:00AM