AN EXAMPLE OF BRIDGE DETERIORATION PROMOTED BY ALKALI- CARBONATE REACTION

FIFTEEN INTERSTATE BRIDGES IN VIRGINIA WERE CONSTRUCTED AT THE SAME TIME IN THE SAME LOCALITY WITH THE SAME MATERIALS AND ENGINEERING DESIGN EXCEPT FOR DIFFERENCES IN THE LITHOLOGIES OF THE COARSE AGGREGATE. IN NINE OF THE STRUCTURES AN ARGILLACEOUS DOLOMITIC LIMESTONE WAS USED; IN SIX A CRYSTALLINE DOLOMITE. BOTH AGGREGATES MEET ABRASION AND SOUNDNESS SPECIFICATIONS. THE LIMESTONE HAS A ROCK PRISM EXPANSION IN ALKALINE SOLUTION OF 1% AT SIX MONTHS, THE DOLOMITE UNDER THE SAME CONDITIONS SHOWS 0% EXPANSION. RECENT SURVEYS OF THE 15 BRIDGES, OPENED TO TRAFFIC IN JULY 1960, SHOW 90 % OF THE SLABS OF THE SIX CONTAINING DOLOMITE FREE OF PATTERN CRACKING AND SCALING, BUT ONLY 15% OF THE SLABS OF THE NINE LIMESTONE CONTAINING BRIDGES FREE OF THESE DEFECTS. THE 15 STRUCTURES HAVE THE SAME EXPOSURE AND MAINTENANCE HISTORY AND THERE ARE NO DIFFERENCES IN THE AIR VOID SYSTEM CHARACTERISTICS OF THE HARDENED CONCRETE WHICH COULD EXPLAIN THE DIFFERENCES IN PATTERN CRACKING AND SCALING FREQUENCY. THE CONCLUSIONS WERE: (1) THE DIFFERENCES IN THE APPEARANCES AND PERFORMANCES OF THE CONCRETES IN THE NORTHERN AND SOUTHERN PROJECTS ARE DUE TO THE DIFFERENCE IN THE COARSE AGGREGATES USED - SINCE ALL OTHER FACTORS ARE THE SAME, (2) SCALING BLOCK TESTS WERE USED TO SIMULATE OR REPRODUCE THE DISTRESS AS SEEN IN THE FIELD; RESULTS FROM THESE TESTS SUGGEST THAT THE INCREASING DISTRESS COULD BE RELATED TO THE INCREASING ALKALI CONTENT OF THE CEMENT, AND (3) FURTHER, RESULTS FROM FREEZING AND THAWING TESTS (WITH VARYING DILUTION OF REACTIVE STONE VS. ALKALI CONTENT) CONFIRMED THAT ALKALI-CARBONATE REACTIVITY, DUE TO INCREASING ALKALI CONTENT, IS A STRONGER DETERMINANT OF PERFORMANCE THAN WHATEVER FREEZE-THAW SENSITIVITY THE STONE MAY HAVE. /AUTHOR/

  • Supplemental Notes:
    • HPR 0669, 0658
  • Corporate Authors:

    Virginia Highway Research Council

    Charlottesville, VA  USA 

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  USA  20590

    Virginia Department of Highways

    Richmond, VA  USA  23219
  • Authors:
    • Ozol, M A
    • Newlon, H H
  • Publication Date: 1971

Subject/Index Terms

Filing Info

  • Accession Number: 00212107
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Files: TRIS, USDOT, STATEDOT
  • Created Date: Jan 31 1972 12:00AM