EXPLORATORY FIELD STUDY OF AGGREGATE-SKID RESISTANCE EFFECTIVENESS

TWENTY-FOUR TEST SECTIONS /SURFACE TREATMENTS/ 11 FT. WIDE AND 2800 FT. LONG PLACED ON A 5.9 MILE LONG MAIN RURAL HIGHWAY, TO DETERMINE THE INFLUENCE OF AGGREGATE TYPE /GRAVEL, LIMESTONE AND SLAG/ SHAPE /CRUSHED AND UNCRUSHED/ AND SIZE /1B, MODIFIED 1B AND S.P. -9 GRADING/ ON SKID RESISTANCE. THE EXPOSURE OF THE TEST SECTIONS TO TRAFFIC WAS DETERMINED FROM A TRAFFIC COUNTER INSTALLED AT THE MIDPOINT OF THE TEST ROAD AND AN ASSUMED NORMAL DISTRIBUTION OF WHEEL PASSES ACROSS THE WHEEL TRACK. MINIMUM AND MAXIMUM AIR TEMPERATURES AND PRECIPITATION WERE RECORDED BY A NEARBY WEATHER STATION. THE TEST CREW PERFORMED AIR AND WET SURFACE TEMPERATURE MEASUREMENTS PRIOR TO RUNNING SKID TESTS. THE SKID RESISTANCE DATA INDICATE THAT THE PAVEMENT WEAR AND AGGREGATE POLISHING PROCESS AND THE RESULTING DECREASE OF THE SKID NUMBER IS OFFSET BY THE INCREASE OF THE SKID NUMBER DUE TO DECREASING AIR AND WET SURFACE TEMPERATURES. PAVEMENT WEAR AND AGGREGATE POLISHING EFFECTS ON SKID RESISTANCE CAN THUS BE EVALUATED ONLY WHEN THE SKID NUMBER- TEMPERATURE GRADIENT IS KNOWN. THE SLAG AND GRAVEL SECTIONS PRODUCED SKID NUMBERS ALMOST TWICE AS HIGH AS THE CRUSHED LIMESTONE SECTIONS. THE ADMIXTURE OF 25 PERCENT BY VOLUME OF SLAG AND GRAVEL TO LIMESTONE SURFACES INCREASED THE SKID RESISTANCE SLIGHTLY, BUT NOT ENOUGH TO OFFSET THE INHERENT SLIPPERINESS OF THE PRINCIPAL AGGREGATE. BY DIVIDING THE SKID NUMBER, MEASURED ON THE LIMESTONE, GRAVEL AND SLAG SECTIONS BY THE CORRESPONDING PLACEMENT COST IN CENTS PER SQUARE YARD, RATIOS OF ABOUT 3.2, 3.9 AND 4.5 ARE OBTAINED, IMPLYING THAT GRAVEL AND SLAG SURFACES ARE MORE ECONOMICAL WHEN MINIMUM SKID RESISTANCE REQUIREMENTS MUST BE MET OVER A PERIOD OF SEVERAL YEARS. THE GENERAL LACK OF CONTROL OVER VARIABLES WHICH AFFECT THE POLISHING PROCESS AND SKID TEST DATA IN THE FIELD AND THE RESULTANT UNCERTAINTIES ASSOCIATED WITH SUCH DATA STRONGLY EMPHASIZES THE NEED FOR DEVELOPMENT OF LABORATORY METHODS WHICH PERMIT THE RAPID AND REALISTIC EVALUATION OF THE POLISHING RESISTANCE OF AGGREGATES AND AGGREGATES MIXTURES UNDER CONTROLLED CONDITIONS AND A RETURN TO FIELD EXPERIMENTS OF THIS NATURE AT A LATER DATE WHEN THE INFLUENCE OF PRINCIPAL PARAMETERS IS UNDERSTOOD. /AUTHOR/

  • Supplemental Notes:
    • Hpr-1/4/, STATE 044, BPR 13
  • Corporate Authors:

    Pennsylvania State University, University Park

    Pennsylvania Transportation Institute, Transportation Research Building
    University Park, PA  United States  16802
  • Authors:
    • KUMMER, H W
    • White, D L
  • Publication Date: 1967-4

Subject/Index Terms

Filing Info

  • Accession Number: 00206304
  • Record Type: Publication
  • Source Agency: Bureau of Public Roads /US
  • Files: TRIS
  • Created Date: Sep 15 1994 12:00AM