LIMESTONE WITH EXCELLENT NON-SKID PROPERTIES

THE PROPERTIES OF LIMESTONE WERE INVESTIGATED TO DETERMINE THE FACTORS WHICH CAUSE GOOD SKID RESISTANCE. LIMESTONE IS DEFINED AS SEDIMENTARY ROCK IN WHICH THE CARBONATE FRACTION EXCEEDS THE NONCARBONATE FRACTION AND IN WHICH THE PREDOMINATING METALLIC ELEMENT OF THE CARBONATE IS CALCIUM. FIVE LIMESTONE AGGREGATES, EACH FROM A DIFFERENT SOURCE, WERE SELECTED FOR INCLUSION IN BITUMINOUS CONCRETE MIXES. REALISTIC TEST SECTIONS WERE PLACED IN A CIRCULAR TEST TRACK AND THEIR SKID RESISTANCE MEASURED WITH A SPECIAL DEVICE DESIGNED FOR THIS PURPOSE. THE FIVE BITUMINOUS MIXTURES WERE FOUND TO DIFFER WIDELY IN SKID RESISTANCE. SAMPLES OF EACH OF THE FIVE AGGREGATES WERE LEACHED WITH HYDROCHLORIC ACID AND THE REMAINDERS FILTERED, WASHED, DRIED, AND WEIGHED. THE PERCENTAGES OF CARBONATES AND INSOLUBLE RESIDUE WERE CALCULATED. THIS RESIDUE WAS TESTED FOR GRAIN SIZE DISTRIBUTION BY THE ASTM METHOD AND FOR SPECIFIC GRAVITY. TWO OF THE LIMESTONES TESTED WERE QUITE SLIPPERY. ONE HAD ONLY A SMALL PORTION OF INSOLUBLES WHILE THE OTHER CONTAINED AN APPRECIABLE AMOUNT OF INSOLUBLES. THERE IS EVIDENCE THAT THE SAND SIZED GRAINS OF THE INSOLUBLES IS THE FACTOR THAT IS EFFECTIVE IN PROMOTING SKID RESISTANCE. DATA INDICATE THAT A COMBINATION OF DIFFERENTIAL HARDNESS, AMOUNT OF INSOLUBLE RESIDUE, AND GRAIN SIZE DISTRIBUTION OF THE INSOLUBLE RESIDUE ARE FACTORS THAT DETERMINE THE SKID RESISTANCE OF LIMESTONE AGGREGATES. IT IS KNOWN THAT BLENDS OF LIMESTONE AGGREGATE AND SILICEOUS SAND IN BITUMINOUS MIXTURES CAN PROVIDE SURFACES WITH ADEQUATE SKID RESISTANCE. IT IS ALSO KNOWN THAT SOME CHERTY LIMESTONES (NODULES) HAVE BEEN USED SATISFACTORLY IN SURFACE COURSE MIXTURES HAVING GOOD SKID RESISTANCE. IT IS BELIEVED THAT THE DATA PRESENTED INDICATE THAT A LIMESTONE POSSESSING THE PROPERTIES GIVEN ABOVE COULD BE USED AS THE ENTIRE AGGREGATE IN SURFACE COURSE MIXTURES WHICH WOULD POSSESS ADEQUATE SKID RESISTANCE.

  • Supplemental Notes:
    • Vol 35, No 48 PP 6-11, 15, 3 TAB, 1 REF
  • Corporate Authors:

    N/A

    ,   USA 
  • Authors:
    • Gray, J E
    • Renninger, F A
  • Publication Date: 1960-12

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Filing Info

  • Accession Number: 00217652
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 1 2003 12:00AM