HALF-CELL POTENTIALS AND THE CORROSION OF STEEL IN CONCRETE

THE HALF-CELL POTENTIAL OF STEEL EMBEDDED IN CONCRETE SPECIMENS IN LABORATORY TESTS WAS PERIODICALLY MEASURED AND RELATED TO THE VISUAL OBSERVATION OF CONCRETE CRACKING. ALTHOUGH CRACKING WAS OBSERVED AT A MINIMAL LEVEL OF -0.31 VOLTS, IT WAS OBSERVED THAT WHEN HALF- CELL POTENTIAL VALUES WERE MORE NEGATIVE THAN -0.42 VOLTS TO BE SATURATED CALOMEL ELECTRODE (SCE), 50% OF THE REINFORCED CONCRETE BLOCKS WERE CRACKED DUE TO THE CORROSION OF THE STEEL. AT VALUES BETWEEN -0.27 AND -0.42 VOLTS, SCE, THE STEEL WAS CORRODING BUT NOT ALWAYS ENOUGH TO CAUSE CONCRETE CRACKING. IN CRACKED CONCRETE, THE MAXIMUM HALF-CELL POTENTIAL OF THE STEEL WAS MEASURED TO BE -0.59 VOLTS, SCE. IN ADDITION TO THE LABORATORY TESTS ON SMALL SPECIMENS, A PROTOTYPE SIMULATED BRIDGE DECK WAS EXPOSED OUTDOORS TO PERIODIC WETTING AND DRYING OF A CHLORIDE SALT SOLUTION AND HALF-CELL POTENTIALS WERE MEASURED BY USING VARIOUS TECHNIQUES. IT IS SHOWN THAT ONCE CORROSION BEGINS, THE MEASUREMENTS WILL SHOW THE POTENTIAL GRADIENTS OF THE RESULTING CORROSION CURRENTS IRRESPECTIVE OF THE TECHNIQUE USED TO OBTAIN THEM. HOWEVER, THERE WAS A SIGNIFICANT DIFFERENCE IN THE LEVEL OF THE POTENTIALS THAT WAS CLEARLY ASSOCIATED WITH THE METHOD OF ELECTRICAL MEASUREMENT USED. /FHWA/

  • Supplemental Notes:
    • REP NO CA-HY-MR-5116-7-72-42 Contract No D-3-11
  • Corporate Authors:

    California Division of Highways

    Materials and Research Department
    Sacramento, CA  United States  95819

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Stratfull, R F
  • Publication Date: 1972-11

Media Info

  • Pagination: 31 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00212129
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Files: TRIS, USDOT
  • Created Date: May 7 1973 12:00AM