FLEXURE OF A ROAD SURFACING, ITS RELATION TO FATIGUE CRACKING, AND FACTORS DETERMINING ITS SEVERITY

THIS PAPER DESCRIBES SOME ASPECTS OF THEORETICAL AND EXPERIMENTAL WORK CARRIED OUT IN SOUTH AFRICA, OVER THE PAST FOUR YEARS, IN A STUDY OF 'CHICKEN NET' CRACKING OF A ROAD SURFACING, AND OF THE FLEXURE INDUCED IN IT BY WHEEL LOADS. THE ACCURACIES OF COMMON MEASURES OF THE SEVERITY OF FLEXURE ARE DISCUSSED. OF THESE, RADIUS OF CURVATURE HAS BEEN ADOPTED FOR GENERAL TESTING. RESULTS OF FIELD OBSERVATIONS WHICH REVEAL A DISTINCT RELATION BETWEEN CURVATURE AND DEGREE OF CRACKING OF A SURFACING ARE PRESENTED, A RADIUS OF ABOUT 125 FT. BEING CRITICAL IN THE CASE OF ONE ROAD STUDIED. A FIELD STUDY IS DESCRIBED WHICH REVEALED THAT ELASTIC THEORY IS APPLICABLE TO A LIMITED EXTENT IN REGARD TO THE DEFLECTION AND CURVATURE OF A ROAD UNDER ITS NORMAL TRAFFIC. A NUMBER OF FACTORS WHICH AFFECT THE SEVERITY OF THE FLEXURE DEVELOPED BENEATH A WHEEL LOAD ARE DISCUSSED. CURVATURES ARE PRACTICALLY INDEPENDENT OF THE NATURE OF THE MATERIALS BELOW A DEPTH OF ABOUT 15 IN., AND DEPEND MAINLY ON THE MATERIALS OF THE BASE AND SUBBASE. CURVATURES ARE AFFECTED CONSIDERABLY BY THE TIRE PRESSURES OF THE VEHICLE INDUCING THEM, BUT LITTLE BY THE WHEEL LOAD. EXISTING DESIGN METHODS DO NOT APPEAR TO TAKE ADEQUATE ACCOUNT OF FLEXURE CRACKING, AND THE LIKELY FORM OF POSSIBLE ADDITIONAL DESIGN CONSIDERATIONS IS DISCUSSED. /AUTHOR/

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/hrbbulletin/321/321-003.pdf
• Supplemental Notes:
  • No 321, pp 26-39, 5 FIG, 2 TAB, 20 REF Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
• Authors:
  • Dehlen, G L
• Conference:
  • 41st Annual Meeting of the Highway Research Board
  • Location: Washington DC, United States
  • Date: 1962-1-8 to 1962-1-12
• Publication Date: 1962

Media Info

• Media Type: Digital/other
• Monograph Title: Flexible pavement design and performance studies
• Serial:
  • Highway Research Board Bulletin
  • Issue Number: 321
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Base course (Pavements); Curvature; Deflection; Design; Elasticity (Mechanics); Fatigue tests; Flexure; Materials; Pavement cracking; Pavements; Pressure; Radius; Subgrade materials; Surface course (Pavements); Tires; Wheel loads
• Uncontrolled Terms: Design criteria
• Old TRIS Terms: Elastic theory; Pavement deflection; Radius of curvature
• Subject Areas: Design; Highways; Materials; Pavements; Vehicles and Equipment;

Filing Info

• Accession Number: 00206755
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Jul 29 1994 12:00AM