JOINT REPORT CONCRETE DURABILITY STUDIES. CASE STUDY 3. SEVERE SCALING OF AN INTERSTATE BRIDGE DECK, AND POTENTIALLY REACTIVE CARBONATE AGGREGATES. PR 6: 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 NONE 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. PETROPHRAPHIC EXAMINATION REVEALS THAT THE ARGILLACIOUS DOLOMITIC LIMESTONE HAS THE FABRIC OF A PROTOTYPICAL ALKALI-REACTIVE CARBONATE ROCK AND THE CONCRETE CONTAINING THIS STONE HAS ABUNDANT HAIRLINE CRACKS PROPAGATING THROUGH BOTH THE PASTE AND THE AGGREGATE. THE OTHER STONE IS A MOSAIC OF EQUIGRANULAR INTERLOCKED DOLOMITE SUBHEDRA AND THE CONCRETE CONTAINING IT IS VIRTUALLY FREE OF SUCH FEATURES. TESTS, USING A NONREACTIVE AGGRAGATE AS A DILUENT AND CEMENT WITH VARYING PERCENTAGES OF ALKALIES, SHOW INCREASING FREEZE-THAW DISTRESS WITH INCREASING ALKALIES OR WITH INCREASING REACTIVE AGGREGATE AT CONSTANT ALKALIES. /AUTHOR/

  • Record URL:
  • Supplemental Notes:
    • Vhrc 70-r42, 23 PP, 20 FIG, 5 TAB, 1 REF
  • Corporate Authors:

    Virginia Highway Research Council

    Charlottesville, VA  United States 
  • Authors:
    • Ozol, M A
    • Newlon, H H
  • Publication Date: 1971-5

Subject/Index Terms

Filing Info

  • Accession Number: 00214041
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Oct 18 1971 12:00AM