RELATIONSHIP OF SKID RESISTANCE TO PETROGRAPHY OF AGGREGATES

RESULTS OF THIS PROJECT SHOW THAT PETROGRAPHIC PROPERTIES OF AGGREGATES PLAY THE CHIEF ROLE IN SKID RESISTANCE ON BITUMINOUS CONCRETE HIGHWAYS. IMPORTANT PETROGRAPHIC PROPERTIES ARE MINERAL HARDNESS, GRAIN OR CRYSTAL SIZE AND ANGULARITY OF GRAINS. THE MOST IMPORTANT SINGLE PROPERTY IS MINERAL HARDNESS. DIFFERENTIAL HARDNESS SUCH AS IS PRESENT IN MOST SANDSTONES (BETWEEN THE GRAIN AND MATRIX) AND IN MOST IGNEOUS AND METAMORPHIC ROCKS (BETWEEN THE VARIOUS COMPONENT MINERALS TENDS TO MAINTAIN A ROUGH TEXTURE UNDER THE WEAR OF TRAFFIC. MAXIMUM POLISH OF LOW SILICA LIMESTONE AGGREGATES WAS ACHIEVED BY 750,000 VEHICLE PASSES WHEREAS A QUARTZITE REQUIRED OVER 2,000,000 FOR MAXIMUM POLISH. WEATHER DEPENDENT FACTORS CAUSE VARIATIONS IN SKID RESISTANCE. THESE MUST BE EVALUATED TO DETERMINE THE TRUE RELATIONSHIP OF PETROGRAPHIC PROPERTIES TO SKID RESISTANCE. THE CHIEF CAUSES OF THESE VARIATIONS ARE CHANGES IN SURFACE TEMPERATURES AND SIZE DISTRIBUTION OF ABRASIVE DETRITUS (RELATED TO QUANTITY AND FREQUENCY OF PRECIPITATION). NORMAL SEASONAL VARIATIONS IN SKID RESISTANCE ARE VERY PRONOUNCED BECAUSE OF COMPOUNDING INFLUENCES. DURING WINTER-SPRING SEASONS, LOW TEMPERATURES AND POLISHING WITH COARSE ABRASIVE DETRITUS (ASSOCIATED WITH FREQUENT PRECIPITATION) BOTH CONTRIBUTE TO HIGH SKID RESISTANCE, WHEREAS, IN SUMMER-FALL SEASONS, HIGH SURFACE TEMPERATURES AND POLISHING WITH FINE ABRASIVES (ASSOCIATED WITH PROLONGED DRY SPELLS) BOTH CONTRIBUTE TO LOW SKID RESISTANCE. /FHWA/

Media Info

  • Pagination: 35 p.
  • Serial:
    • Issue Number: 3

Subject/Index Terms

Filing Info

  • Accession Number: 00206508
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Report/Paper Numbers: Final Rept
  • Files: TRIS, USDOT, STATEDOT
  • Created Date: Sep 17 1973 12:00AM