EXPERIMENTAL CAHTODIC PROTECTION OF A BRIDGE DECK

AN ELECTRICALLY CONDUCTIVE ASPHALT CONCRETE WAS MADE BY SUBSTITUTING COKE BREEZE FOR THE NATURAL AGGREGATE. BY PAVING A BRIDGE DECK WITH THE ELECTRICALLY CONDUCTIVE ASPHALT CONCRETE, IT WAS FOUND THAT CATHODIC PROTECTION COULD BE APPLIED TO THE REINFORCING STEEL. THE CATHODIC PROTECTION WAS MEASURED TO BE EFFECTIVE WHEN CORROSION OF STEEL STRIPS IMBEDDED IN CONCRETE CONTAINING 10% CALCIUM CHLORIDE BY WEIGHT OF THE CEMENT WAS STOPPED. IT IS ESTIMATED THAT FOR THE APPROXIMATELY 330 SQUARE FEET (307.6 SQ M) OF BRIDGE DECK UNDER CATHODIC PROTECTION, THE TOP MAT OF REINFORCING STEEL HAS AN APPLIED CURRENT DENSITY OF 0.7 MILLIAMPERES (MA) PER SQUARE FOOT (7.5 MA/SQ M) OF STEEL SURFACE. THE TOTAL CURRENT USED IS ABOUT 1.0 AMPERE WITH A DRIVING VOLTAGE OF 1.65 VOLTS FOR A TOTAL POWER REQUIREMENT OF 1.65 WATTS. AS AN EXPERIMENTAL METHOD OF REPAIR, TWO POLYMERS AND AN EPOXY WERE INJECTED TO BOND THE UNDERSURFACE FRACTURES. IT WAS OBSERVED THAT THE EPOXY COULD BE INJECTED TO EFFECT A REPAIR ONLY UNDER CERTAIN CONDITIONS. IN ALL CASES WHERE THE CONCRETE EMITTED A HOLLOW SOUND. /FHWA/

Media Info

  • Pagination: 56 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00208126
  • Record Type: Publication
  • Source Agency: California Department of Transportation
  • Report/Paper Numbers: FHWA-RD-74- 31 Intrm Rpt., FCP 44B1-072
  • Contract Numbers: D-3-12
  • Files: TRIS, STATEDOT
  • Created Date: Jun 11 1976 12:00AM