Impedance-Based Detection of Corrosion in Post-Tensioned Cables: Phase 2 from Concept to Application

Indirect impedance was explored as a non-destructive means of detecting active corrosion in post-tensioned tendons used in segmentally constructed bridges. The research program included both fundamental studies to quantify corrosion rates and oxide film thicknesses for ASTM A416 steel in simulated pore solutions and in grout and practical studies to determine how indirect impedance may be employed in field applications. Indirect impedance was found to provide a means of detecting corrosion in tendons if the corroding strands are located near the grout-duct interface and are directly under one of the two current injection electrodes. The indirect impedance approach is only qualitative because the grout impedance obscures quantification of the corrosion rate. Corrosion of strands in the center of a duct containing many strands cannot be detected by indirect impedance. These conclusions are supported by experimental observations and numerical simulations. Thus, indirect impedance may be useful if corrosion can be anticipated to occur in response to grout segregation, for which corroding strands will be located near the top of tendons. The procedure for the indirect impedance measurement is relatively simple, and the instrumentation required can weigh less than 20 pounds. Measurements are performed in approximately 20 minutes, and the holes that are drilled can be sealed if desired.


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Figures; References; Tables;
  • Pagination: 104p

Subject/Index Terms

Filing Info

  • Accession Number: 01643595
  • Record Type: Publication
  • Contract Numbers: BDV31-977-35
  • Created Date: Aug 9 2017 12:09PM