Corrosion of the reinforcing steel in bridge decks is described as being caused by the penetration of de-icing salts, leading to the passage of an electrical current from the surface of the steel through the concrete by means of the moisture in the concrete to another location on the steel. The use of cathodic protection to combat corrosion is described whereby an external direct current is applied to the surface of the top mat of steel in sufficient amounts to overcome the internal current flow. Reference is made to a demonstration project located on the George Washington Memorial Parkway Bridge, near Washington, D.C. The installation of the equipment in the two southbound lanes of the bridge is described. Two types of asphalt mix were used on the project. One was a coke-breeze mixture, consisting of coke-breeze (a lightweight residue from the coke-making process, valuable for its high carbon - or electrical conductivity - properties), plus a higher than normal percentage of liquid asphalt (approximately 23 per cent by weight of mix caused by the high absorptive characteristics and low density of the coke-breeze). The second asphalt mix used was a standard grading e (Virginia Department of Highways S-5) used to overlay the coke-breeze mixture. Electrical power is derived from a solar panel installation which cost $4620 as opposed to $13954 for a commercial electrical installation. The solar electric power system is described as a power source composed of a solar panel array mounted on a post alongside the bridge, a battery, and blocking diodes to prevent the battery from discharging through the solar panels at night. /TRRL/

  • Availability:
  • Corporate Authors:

    Shell International Petroleum Company Limited

    Shell Center
    London SE1 7NA,   England 
  • Publication Date: 1978-6


  • English

Media Info

  • Features: Photos; Tables;
  • Pagination: p. 16-7
  • Serial:
    • Shell Bitumen Review
    • Issue Number: 57
    • Publisher: Shell International Petroleum Company Limited
    • ISSN: 0037-3516

Subject/Index Terms

Filing Info

  • Accession Number: 00184531
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Feb 3 1979 12:00AM