Magnetic Flux Leakage Method for Detecting Corrosion in Post Tensioned Segmental Concrete Bridges in Presence of Secondary Reinforcement

A significant portion of in service concrete bridges are prone to damages due to corrosion and deterioration due to aging. The study describes the use of Magnetic Flux Leakage (MFL) method for detection of corrosion simulated as geometrical discontinuity in strands. The MFL method is robust and accurate in detection of geometrical discontinuity in high strength strands alone. However, the presence of secondary ferromagnetic sources, such as mild reinforcement in Prestressed concrete members, signals are obscured and detection of defects in strands are made more challenging. The study investigates the possibility of identifying the damage in strands by using MFL method in the presence of secondary ferromagnetic materials. The concept is used for experimental tests by inducing different damage scenarios in strands and measuring flux leakage in the active and residual magnetic fields. Effects of damage size, change in polarization, presence of metallic sheathing around the strands and depth of damage is studied. The laboratory test setup used in preliminary work has shown the capability to detect damage as low as 14% in presence of mild reinforcement with expectations for future improvements. The concept is extended to testing of a bridge segment with a dense mesh of mild reinforcement besides the strands. The difference in voltage representing magnetic flux density of tests in active magnetic field is able to identify the full geometric discontinuity of strands in the bridge segment.

  • Supplemental Notes:
    • This paper was sponsored by TRB committee AHD45 Standing Committee on Corrosion.
  • Corporate Authors:

    Transportation Research Board

    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Authors:
    • Rehmat, Sheharyar e
    • Sadeghnejad, Amir
    • Valikhani, Alireza
    • Chunn, Brian
    • Lau, Kingsley
    • Azizinamini, Atorod
  • Conference:
  • Date: 2017


  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; Photos; References; Tables;
  • Pagination: 16p
  • Monograph Title: TRB 96th Annual Meeting Compendium of Papers

Subject/Index Terms

Filing Info

  • Accession Number: 01626619
  • Record Type: Publication
  • Report/Paper Numbers: 17-05231
  • Files: TRIS, TRB, ATRI
  • Created Date: Feb 27 2017 9:25AM