FREEZE-THAW DURABILITY OF MICHIGAN CONCRETE COARSE AGGREGATES

THE MICHIGAN HIGHWAY DEPARTMENT IS CURRENTLY CALLED UPON TO APPROVE, EACH YEAR, COARSE AGGREGATE FOR APPROXIMATELY ONE MILLION CUBIC YARDS OF CONCRETE. THESE AGGREGATES ARE FURNISHED FROM DEPOSITS RANGING IN SIZE FROM ROADSIDE PITS TO LARGE WELL-ESTABLISHED COMMERCIAL SOURCES AND ARE DISTRIBUTED OVER AN AREA EXCEEDING 600 MILES BETWEEN EXTREMITIES. THERE IS EVERY INDICATION THAT THE RATE OF AGGREGATE CONSUMPTION WILL INCREASE WITH THE ACCELERATED HIGHWAY CONSTRUCTION PROGRAM. THIS WILL SURELY REQUIRE EVALUATION OF THE FREEZE-THAW DURABILITY, BOTH OF DEPOSITS NOW CONSIDERED OF MARGINAL QUALITY AND OF ENTIRELY NEW SOURCES AS PROVEN AGGREGATE RESERVES BECOME DEPLETED. THE PRESENT PAPER PRESENTS LABORATORY FREEZE-THAW RESULTS AS WELL AS FIELD OBSERVATIONS ON THE MAJOR MICHIGAN AGGREGATE SOURCES AND IS CONSIDERED A FIRST STEP IN FORMULATION OF A POLICY REGARDING ACCEPTANCE OF FUTURE AGGREGATES OF UNKNOWN SERVICE BEHAVIOR. BRIEF DESCRIPTION IS MADE OF AUTOMATIC FREEZE-THAW EQUIPMENT WHEREIN CONSIDERABLE COST WAS SAVED BY UTILIZING AN EXISTING LARGE COLD ROOM AS THE SOURCE OF FREEZING MEDIUM. SIX CYCLES PER DAY ARE OBTAINED USING EITHER RAPID FREEZING IN AIR AND THAWING IN WATER, OR RAPID FREEZING IN WATER AND THAWING IN WATER. BOTH TYPES OF CYCLE CAN BE OBTAINED SIMULTANEOUSLY IF DESIRED. EVERY EFFORT HAS BEEN MADE TO PROVIDE A RUGGED TROUBLE-FREE DESIGN. THE EQUIPMENT HAS NOW OPERATED CONTINUOUSLY FOR TWO YEARS WITH A MINIMUM OF ATTENTION. LABORATORY EVALUATION OF COARSE AGGREGATE DURABILITY IS ACHIEVED BY FOLLOWING A RIGIDLY STANDARDIZED PROCEDURE WHEREIN THE AGGREGATES ARE GRADED AND PLACED IN AIR-ENTRAINED CONCRETE IN A VACUUM SATURATED CONDITION. THE ASTM RAPID CYCLE OF FREEZING IN AIR TO OF AND THAWING IN 40F WATER IS USED. FAILURE IS CONSIDERED TO HAVE OCCURRED WHEN THE SONIC MODULUS OF 3-BY4-BY16-INCH SPECIMENS HAS DECREASED 30 PERCENT. DURABILITY FACTORS AT 300 CYCLES OF FREEZING AND THAWING APPEAR TO ADEQUATELY DESCRIBE THE BEHAVIOR OF THE AGGREGATES. DATA ARE PRESENTED GIVING DURABILITY FACTORS OF THE MAJOR AGGREGATE SOURCES, AND ALSO FROM THREE PLANTS USING HEAVY MEDIA METHODS OF GRAVEL IMPROVEMENT. RESULTS OF A SPECIAL SERIES OF TESTS ARE PRESENTED WHEREIN THE EFFECT OF CHERT STILL REMAINING IN THE HEAVY MEDIA IMPROVED GRAVEL IS EVALUATED. THE RESULTS INDICATE THAT THIS HIGH GRAVITY CHERT IS FAR LESS HARMFUL THAN LOW GRAVITY CHERT. CORRELATION WITH THE MAGNESIUM SULFATE SOUNDNESS TEST WAS FOUND TO BE DOUBTFUL. THE LABORATORY DURABILITY RESULTS CORRELATE REASONABLY WELL WITH KNOWN SERVICE BEHAVIOR AND IT NOW SEEMS POSSIBLE TO PROVIDE THE HIGHWAY ADMINISTRATOR WITH RELIABLE FACTUAL DATA FOR PROPER DECISION. /AUTHOR/

Media Info

  • Monograph Title: Freeze-thaw durability of aggregate in concrete
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00217781
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Jul 28 1994 12:00AM