STRAY CURRENT AND GALVANIC CORROSION OF REINFORCING STEEL IN CONCRETE

Experiments were performed with steel reinforced hydraulic concrete exposed to running fresh sea water simulating a bridge structure. Various configurations of contact and circuits were employed to impress on and measure electrical parameters on the structure metals. Both DC and AC potentials were imposed on the structure at various locations to determine what effect they would have on the electrical confiquration of the structure and to anticipate what effects can be expected in the case of stray currents or galvanic effects. It was concluded that small increments of stray current could attack the steel and/or cause concrete cracking. AC current may be feebly rectified. It could not be determined if AC affected the normal passivity of the steel in concrete. Magnitude of stray currents in concrete are more a function of electrochemical reactions at steel-concrete interface than by concrete resistance. Metallic attachments to reinforced concrete require sufficient insulation to avoid electrical circuits through surface chlorides or saturated concrete or plastic. Galvanic coupling to metals or to steel whose solution potentials differ from the reinforcing can produce significant currents. Small areas of anodic steel can polarize the concrete-encased steel. /AUTHOR/

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  • Corporate Authors:

    National Association of Corrosion Engineers

    P.O. Box 1499
    Houston, TX  United States  77001
  • Authors:
    • Miller, R L
    • Hartt, W H
    • Brown, R P
  • Publication Date: 1976-5

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Filing Info

  • Accession Number: 00135872
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 23 1976 12:00AM