CATHODIC PROTECTION DEVELOPMENTS FOR PRESTRESSED CONCRETE COMPONENTS. FINAL REPORT

This is the final report in a study that evaluated the feasibility of using cathodic protection on prestressed concrete bridge members. The interim report (FHWA-RD-92-056), published in February 1993, presented laboratory data showing that cathodic protection will generate hydrogen on high-strength steel embedded in concrete if the potential is more negative than the thermodynamic hydrogen evolution potential. The hydrogen generated will enter the steel and will cause a loss in ductility that will adversely affect the steel's performance if a notch is present. In addition, conductive paints and polymers were evaluated as anode materials. Full-scale beams were constructed to study the above phenomena, as well as the various cathodic protection criteria. Four pretensioned beams were constructed. In addition, two post-tensioned slabs were constructed to evaluate the ability of cathodic current to provide corrosion protection to anchorages and tendons encased in metal or plastic conduits. Cathodic protection currents were supplied by IR drop-free potential controlled rectifiers. Later in the study, constant-current power supplies were utilized. The interim report presented the initial construction details and preliminary results for the beams and slabs. Hydrogen entering the steel as the result of corrosion appears to have masked the presence of hydrogen that might have been produced by cathodic protection applied at levels exceeding -1100 mV vs. CSE. The analysis also revealed that there was corrosion of some pretensioned wires at crossings with interior steel reinforcing bars due to interference (stray current) caused by cathodic protection application. Analysis of the post-tensioned slabs indicates little effect on tendons inside plastic or metal ducts from the application of cathodic protection. Beneficial effects were noted on anchor points where mortar was in contact with the metal. None of the anode systems tested proved to be fully durable under the conditions of the test.

  • Corporate Authors:

    PSG Corrosion Engineering, Incorporated

    610 Brandywine Parkway
    West Chester, PA  United States  19380

    Federal Highway Administration

    Turner-Fairbank Highway Research Center, 6300 Georgetown Pike
    McLean, VA  United States  22101
  • Authors:
    • Funahashi, M
    • Wagner Jr, J
    • Young, W T
  • Publication Date: 1994-7

Language

  • English

Media Info

  • Features: Figures; Photos; Tables;
  • Pagination: 132 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00666252
  • Record Type: Publication
  • Report/Paper Numbers: FHWA-RD-94-001, 3D4b2112
  • Contract Numbers: DTFH61-88-C-00054
  • Files: TRIS, USDOT
  • Created Date: Sep 22 1996 12:00AM