Electrochemical chloride extraction : influence of concrete surface on treatment.

Details

• Creators:
  Sharp, Stephen R. ; Clemeiia, Gerry G. ; Vinnani, Y. Paul ; Stoner, Glenn E. ; Kelly, Robert G.
• Corporate Creators:
  Virginia Transportation Research Council (VTRC)
• Corporate Contributors:
  United States. Department of Transportation. Federal Highway Administration. Office of Infrastructure Research and Development
• Subject/TRT Terms:
  • Corrosion protection
  • Cathodic protection
  • Chloride content
  • Ions
  • Reinforced concrete
  • Corrosion
  • Corrosion resistance
  • Corrosion resistant steel
  • Electrochemical corrosion
  • Cathodic protection
  More +
• Publication/ Report Number:
  FHWA-RD-02- 107;VTRC 02-R
• Resource Type:
  Tech Report
• Geographical Coverage:
  Virginia
• Edition:
  Interim report.
• Corporate Publisher:
  Turner-Fairbank Highway Research Center
• Abstract:
  One bridge restoration technique available for reducing corrosion-induced concrete deterioration, which removes ; chloride ions while simultaneously realkalizing the concrete adjacent to the steel, is electrochemical chloride extraction ; (ECE). Studies have shown that ECE is capable of removing, in a single application, a significant portion of the chloride ; ions fiom a reinforced concrete structure. Prior research has also shown that the quantity of chloride ions removed is ; dependent on numerous factors including quantity and spacing of reinforcing steel, applied voltage, initial chloride ; concentration, etc. In addition, investigations into chloride binding and competition between other ions as current carriers ; have helped to clarify the probable mechanisms responsible for decreases in current efficiency with time during chloride ; removal. ; This portion of the investigation has focused on the influence of water-to-cement (wlc) ratio. In addition, an ; investigation was conducted to identify the cause of decrease in efficiency during chloride removal. A clear relationship ; between the w/c ratio and the chloride extraction rate was not evident. However, the investigation revealed that the ; resistance of the concrete surface layer increases considerably during ECE, which effectively restricts the current flow, while ; the resistance of the underlying layer of concrete either decreases orremains constant. It appears that the increased ; resistance of the surface layer concrete is accompanied by the formation of a tightly adhering residue on the concrete surface. ; Preliminary analysis of the surface formation indicates it contains calcium carbonate and calcium chloride.
  More +
• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/25306/dot_25306_DS1.pdf
• File Type:
  [PDF - 5.58 MB]
• Collection(s):
  Federal Highway Administration ; US Transportation Collection
• Main Document Checksum:
  urn:sha-512:4b4c3fc5369fdfe5ad56350461121e0dc3439a2864c9a5de58a3b418050080a6d34c040b9ecda41058598d75d91e15ef05df27fe1f3dcc59a57a2bef61f53ee0