CORROSION AUTOPSY OF A STRUCTURALLY UNSOUND BRIDGE DECK

AN INVESTIGATION WAS PERFORMED ON A 12-YEAR OLD DEICING SALT-CONTAMINATED REINFORCED CONCRETE BRIDGE DECK WHICH HAD TO BE REPLACED BECAUSE OF ITS DETERIORATED CONDITION. IN THIS INVESTIGATION, THE ELECTRICAL HALF-CELL POTENTIAL MEASUREMENTS AND CHLORIDE ANALYSIS WERE FOUND TO BE RELATED TO THE MASSIVE CORROSION OF THE STEEL. THE EFFECT OF CHLORIDES PRESENT SEEMS TO BE RELATED TO SOME THRESHOLD AMOUNT THAT CHANGES THE STEEL FROM A PASSIVE TO ACTIVE STATE. BEYONG THIS POINT THE AMOUNT OF SALT PRESENT HAS LITTLE OR NO EFFECT EXCEPT AS IT MIGHT INFLUENCE THE AREA OF CORRSION INVOLVED. THE CHAINING OR SOUNDING OF THE DECK TO LOCATE DELAMINATED CONCRETE PERFORMED THAT FUNCTION VERY WELL, BUT DID NOT NECESSARILY LOCATE THE CORRODED STEEL. FROM THE OBSERVATION OF THE TYPE OF CRACKING, IT APPEARED THAT THE FINAL MODE OF DISTRESS WAS CONCRETE FATIGUE. AN INVESTIGATION OF ACTUAL CONCRETE COVER DISCLOSED THAT THERE WAS REINFORCING STEEL CORROSION AT DEPTHS GREATER THAN 3 INCHES. IT WAS DETERMINED THAT ESTIMATING THE PIT DEPTH OF STEEL BY VISUALLY ESTIMATING THE THICKNESS OF RUST IS NOT A VERY USEFUL INSPECTION TECHNIQUE. IN THIS HIGHLY SALT CONTAMINATED BRIDGE DECK, NO RELATIONSHIP WAS FOUND BETWEEN VARIATIONS IN THE CHLORIDE CONTENT OF THE CONCRETE AND THE RELATIVE SEVERITY OF THE CORROSION OF THE STEEL. /FHWA/

• Supplemental Notes:
  • REP NO CA-HY-MR-5116-8-72-41 Contract No D-3-11
• Corporate Authors:

  California Division of Highways

  Materials and Research Department
  Sacramento, CA  United States  95819
• Authors:
  • Stratfull, R F
  • Van, MATRE V
• Publication Date: 1973-1

Media Info

• Pagination: 44 p.

Subject/Index Terms

• TRT Terms: Chlorides; Concrete; Corrosion; Deicing chemicals; Delamination; Deterioration; Fatigue (Mechanics); Reinforced concrete; Reinforcing steel; Rusting; Salts
• Uncontrolled Terms: Deteriorated concrete
• Subject Areas: Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00215986
• Record Type: Publication
• Source Agency: Federal Highway Administration
• Files: TRIS, USDOT
• Created Date: May 7 1973 12:00AM