INTERIM REPORT COVERING 1970 SKID-TRAILER DATA

RESULTS OF A STATEWIDE SURVEY OF THE SLIPPERINESS OF EXISTING PAVEMENTS ARE ANALYZED. THE TESTS WERE RUN USING A TWO WHEEL SKID TRAILER MEETING THE REQUIREMENTS OF ASTM SPECIFICATION E-274-65T AND EQUIPPED WITH TIRES MEETING ASTM SPECIFICATION E-249-66. ALL DATA INCLUDED IN THIS REPORT WERE OBTAINED BY LOCKING THE LEFT WHEEL ONLY. ABOUT 3500 TESTS WERE RUN ON 22 DIFFERENT TYPES OF PAVEMENT SURFACES. THE DATA WERE SEPARATED ACCORDING TO TYPE, SPECIFICATION NUMBER, AND COARSE AGGREGATE INVOLVED. TRAFFIC COUNTS FOR EACH SECTION TESTED WERE COMBINED WITH YEARS-OF-SERVICE TO DEVELOP FOR EACH TEST SITE A WEAR FACTOR, DEFINED AS THE ADT MULTIPLIED BY YEARS-OF-SERVICE DIVIDED BY 1000. WEAR FACTORS WERE PLOTTED AGAINST SKID NUMBERS, DEFINED AS THE COEFFICIENT OF FRICTION BETWEEN THE TIRE AND THE PAVEMENT SURFACE MULTIPLIED BY ONE HUNDRED, TO SHOW THE DECREASE IN SKID NUMBER THAT ACCOMPANIED AN INCREASE IN WEAR FACTOR. THIS IS GENERALLY ACCEPTED AS AN INDICATION OF THE RATE OF POLISHING. THE PAVEMENTS TYPES WERE ANALYZED ON THE BASIS OF THREE CRITERIA ADOPTED BY THE ALABAMA HIGHWAY DEPARTMENT: (1) A PAVEMENT WITH A SKID NUMBER OF 34 OR BELOW IS DANGEROUSLY SLIPPERY AND NEEDS ATTENTION. (2) A PAVEMENT WITH A SKID NUMBER BETWEEN 35 AND 43 INCLUSIVE REQUIRES CAUTION ON THE PART OF THE DRIVER WHEN THE PAVEMENT IS WET. (3) A PAVEMENT WITH A SKID NUMBER ABOVE 43 IS RELATIVELY SAFE EVEN WHEN WET. THE ANALYSIS IS PRESENTED FIRST FOR THE CONDITION OF THE PAVEMENT AT THE TIME IT WAS TESTED, REGARDLESS OF THE TRAFFIC LOAD THAT IT HAD BEEN SUBJECTED TO; AND SECOND IN COMPARISON WITH OTHER PAVEMENTS HAVING THE SAME WEAR FACTORS. THE REPORT INCLUDES A COMPARISON OF PAVEMENT TYPES AT SPECIFIC WEAR FACTOR. /AUTHOR/

• Corporate Authors:

  Alabama State Highway Department

  11 South Union Street
  Montgomery, AL  United States  36130

  Auburn University

  Auburn, AL  United States  36830

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Bransford, T L
• Publication Date: 0

Subject/Index Terms

• TRT Terms: Average daily traffic; Coarse aggregates; Coefficient of friction; Evaluation; Moisture content; Pavement performance; Pavements; Polished aggregates; Skid resistance; Skid resistance tests; Skid trailers; Skidding; Slipperiness; Wear
• Uncontrolled Terms: Skid number; Wet conditions
• Subject Areas: Highways; Pavements;

Filing Info

• Accession Number: 00206473
• Record Type: Publication
• Source Agency: Federal Highway Administration
• Report/Paper Numbers: Study No 930-043
• Files: TRIS, USDOT, STATEDOT
• Created Date: Apr 2 1972 12:00AM