FATIQUE OF FLEXIBLE PAVEMENTS

FIVE ASPHALTIC CONCRETE PAVEMENT THICKNESSES, EACH OF WHICH MEASURED 20X30 FT. AND CONTAINED TWO TEST AREAS, WERE CONSTRUCTED ON A 48" COMPACTED CLAY SUBGRADE. CERTAIN OF THESE PAVEMENT AREAS WERE FATIGUE LOADED THROUGH CONCENTRIC RINGS COMPOSED OF TRUCK TIRE RUBBER BY SUPERIMPOSING ONE DYNAMIC 10 HZ HAVERSINE PULSE ON A SMALL STATIC LOAD EVERY SECOND TO SIMULATE A CONTINUOUS LINE OF WHEEL LOADS TRAVELING IN IDENTICAL WHEEL PATHS 50' APART AT 40 MPH. SURFACE TANGENTIAL STRAIN, SURFACE DEFLECTION AND TEMPERATURE SENSORS WERE PLACED AT A NUMBER OF RADII FROM THE LOAD PLATE CENTERLINE AND RECORDED PERIODICALLY THROUGHOUT EACH TEST. THE FATIGUE OF FOUR OF THESE PAVEMENTS, AS EVIDENCED BY VISIBLE CRACKING, WAS OBSERVED CLOSELY AND NOTED IN A LOG BOOK. ASPHALT AND COMPACTED SUBGRADE SAMPLES WERE RETURNED TO THE LABORATORY FOR THE DETERMINATION OF STRUCTURAL STRENGTH AND PHYSICAL PROPERTIES. THE RESULTS OF THESE TESTS WERE ENTERED INTO THE CHEVRON N-LAYER PROGRAM ALONG WITH A NUMBER OF HYPOTHETICAL MODULI FOR THE NATURAL SUBGRADE UNDERLYING THESE LAYERS. THEORETICAL STRAIN AND DEFLECTION PROFILES OBTAINED FROM THESE CALCULATIONS WERE COMPARED TO MEASURED PROFILES TO DETERMINE THE BEST AVERAGE APPARENT MODULUS FOR THIS SEMI-INFINITE LAYER. TRAPEZOIDAL SPECIMENS WERE SAWED FROM ASPHALT PAVEMENT BLOCKS AND FATIGUE LOADED WITH ONE 10 HZ HAVERSINE PULSE PER SECOND OVER A WIDE RANGE OF TEMPERATURES AND STRAIN LEVELS. AN EQUATION RELATING THESE QUANTITIES TO FATIGUE LIFE WAS DEVELOPED AND COUPLED WITH A THEORETICAL PAVEMENT FATIGUE MODEL TO PREDICT, WITHIN PLUS OR MINUS 20%, THE TIME OF INITIAL SURFACE CRACKING ON THE FOUR FIELD TESTS WHERE VISIBLE CRACKS WERE OBSERVED. FINITE ELEMENT TECHNIQUES WERE EMPLOYED TO STUDY THE EFFECTS OF RINGED VERSUS SOLID LOAD PLATE GEOMETRY AND RADIAL SHEAR FORCES. /AUTHOR/

• Corporate Authors:

  Ohio State University, Columbus

  190 North Oval Drive
  Columbus, OH  United States  43210

  Ohio Department of Highways

  Columbus, OH  United States  43210

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Coffman, B J
  • Ilves, G J
  • Edwards, W F
• Publication Date: 0

Subject/Index Terms

• TRT Terms: Asphalt concrete; Deflection; Equations; Fatigue (Mechanics); Finite element method; Flexible pavements; Mathematical models; Pavement cracking; Pavements; Strain (Mechanics); Subgrade (Pavements); Temperature sensors; Thickness; Wheel loads
• Uncontrolled Terms: Fatigue life; Models; Pavement thickness
• Old TRIS Terms: Finite elements; Tangential strain
• Subject Areas: Highways; Materials; Pavements;

Filing Info

• Accession Number: 00206444
• Record Type: Publication
• Source Agency: Federal Highway Administration
• Report/Paper Numbers: Ees-296
• Files: TRIS, USDOT
• Created Date: Aug 8 1971 12:00AM