INVESTIGATION OF CHLORIDE MIGRATION IN REINFORCED CONCRETE UNDER APPLICATION OF CATHODIC PROTECTION

This project was initiated to examine the mobility of the chloride ion in concrete under cathodic protection and to discover whether long term application reduces the chloride ion content in the concrete surrounding the reinforcing steel. The effect of power interruptions in these systems, the rate of recovery from them, and the possibility that a minimal current density could maintain an established cathodic protection system were other factors examined. The study found evidence of chloride migration in reinforced concrete slabs under cathodic protection at an elevated current density of 50 ma/square metre. For concrete protected at a more typical current density of 10 ma/square metre, no chloride movement was detected over the duration of the tests (469 days). It was estimated that approximately 4% of the current flowing through a system under cathodic protection was transported by chloride ions. Upon removal of the cathodic protection from a slab in which a chloride concentration profile was well characterized and which increased with distance from the rebar, it was found that a significant amount of chloride ions migrated back toward the rebar over a six month period. Similarly, upon reduction of cathodic protection current density from 50 ma/square metre to 1 ma/square metre the same effect was observed. (TRRL)

• Corporate Authors:

  Ontario Ministry of Transportation

  Research and Development Branch, 1201 Wilson Avenue
  Downsview, Ontario  Canada  M3M 1J8
• Authors:
  • Poland, J
  • Page, J A
• Publication Date: 1988-5

Language

• English

Media Info

• Pagination: 46 p.

Subject/Index Terms

• TRT Terms: Chlorides; Corrosion; Electrodes; Loss and damage; Material reinforcement; Motion; Prevention; Reinforced concrete; Slabs; Steel
• ITRD Terms: 5252: Corrosion; 1614: Damage; 6951: Electrode; 7314: Halide; 5483: Movement; 9149: Prevention; 4794: Reinforced concrete; 3471: Reinforcement (in mater); 3491: Slab; 4542: Steel
• Subject Areas: Bridges and other structures; Highways; Materials; Security and Emergencies;

Filing Info

• Accession Number: 00499142
• Record Type: Publication
• Source Agency: Transport and Road Research Laboratory (TRRL)
• Files: ITRD, TRIS
• Created Date: Sep 30 1990 12:00AM