DEVELOPMENT OF ASPHALT INSTITUTE THICKNESS DESIGN RELATIONSHIPS

BASED ON EXTENSIVE ANALYSIS OF THE AASHO AND WASHO ROAD TESTS, BRITISH TEST ROADS AND DATA FROM OTHER SOURCES, THE ASPHALT INSTITUTE HAS RECENTLY PUBLISHED A NEW EDITION OF ITS PAVEMENT STRUCTURAL DESIGN MANUAL. THIS PAPER DISCUSSES THE THEORY AND COMPUTATIONS DEVELOPED TO EXTEND ACTUAL FIELD TEST DATA TO A FULL RANGE OF DESIGN APPLICATION. THE AASHO ROAD TEST EQUATION VALUE OF T /THICKNESS/ IS RELATED TO NUMBER OF REPETITIONS OF LOAD L AND SIZE OF LOAD L. THE COEFFICIENT FOR L IS FOUND CONSTANT FOR ALL LOADS ABOVE 10,000 LBS. AND A FUNCTION OF THE LOAD /L/ FOR THOSE SMALLER. THE SERVICEABILITY INDEX CONCEPT IS USED IN DERIVING THE VALUES OF COEFFICIENTS IN THE DESIGN EQUATIONS. THE DESIGN THICKNESS IS BASED ON A SUBGRADE SOILS STRENGTH TEST VALUES ON THE AASHO ROAD TEST AND DESIGN THICKNESS CORRECTED TO OTHER SUBGRADE STRENGTH VALUES BY USE OF RELATIONSHIPS PREVIOUSLY DEVELOPED. THE DESIGN THICKNESS VALUES ARE BASED ON TOTAL NUMBER OF 18,000 LB. SINGLE AXLE LOAD APPLICATIONS TO A PSI LEVEL OF 2.5 AND METHODS ARE DEVELOPED FOR CONVERTING MIXED SINGLE AXLE AND TANDUM AXLE LOADS OF VARYING SIZES TO EQUIVALENT DESIGN AXLE LOADS. /NAPA/

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Filing Info

  • Accession Number: 00205321
  • Record Type: Publication
  • Source Agency: National Asphalt Pavement Association (NAPA)
  • Files: TRIS
  • Created Date: Mar 24 1994 12:00AM