RATIONAL DETERMINATION OF PAVEMENT LAYER STRUCTURAL COEFFICIENTS

Seven flexible pavements ranging from interstate to state route are selected. Three different approaches are employed. The first two use the resilient modulus of the material to estimate its structural coefficient. In the first approach, cored specimens are obtained from each of the pavement sections and the resilient moduli of in-service 301 and 446/448 materials are determined in the laboratory. The resulting structural coefficient for 301 materials ranges between 0.33 and 0.39 with an average of 0.37. The structural coefficient of 446/448 materials ranges between 0.46 and 0.54 with an average value of 0.49. The second approach backcalculates layer elastic modulus from measured pavement deflection. The resulting structural coefficients are 0.44 for 301 materials (range: 0.25-0.53) and 0.55 for 446 materials (range: 0.38-0.60). The third approach determines the structural coefficient from the AASHTO flexible pavement performance equation based on traffic and serviceability history data. When laboratory measured roadbed soil resilient moduli are used, the average coefficient is 0.42 for 301 materials and 0.52 for 446 materials. When backcalculated roadbed modulus values (multiplied by a factor of 0.33) are used, the average coefficient is 0.30 for 301 and 0.43 for 446 materials. Finally, when the soil modulus is estimated from the group index, the average structural coefficient is 0.39 for 446/448 and 0.26 for 301 materials. The findings of this study indicate that the structural coefficient for 446 materials may be increased from the current value of 0.35 to a value between 0.40 and 0.45. For 301 materials, a structural coefficient between 0.35 and 0.37 is recommended.

• Record URL:
  https://ntlrepository.blob.core.windows.net/lib/15000/15800/15819/PB2000101094.pdf
• 
• Corporate Authors:

  University of Toledo

  Department of Civil Engineering, 2801 West Bancroft Street
  Toledo, OH  United States  43606-3390

  Ohio Department of Transportation

  1980 West Broad Street
  Columbus, OH  United States  43223

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Chou, EYJ
  • Randolph, B
  • Heydinger, A
• Publication Date: 1999-5

Language

• English

Media Info

• Features: Appendices; Figures; References; Tables;
• Pagination: 94 p.

Subject/Index Terms

• TRT Terms: Backcalculation; Core samples; Deflection; Equations; Flexible pavements; Laboratory tests; Layer coefficient (Pavements); Modulus of resilience; Pavement layers; Pavement performance
• Subject Areas: Data and Information Technology; Design; Highways; Pavements; I22: Design of Pavements, Railways and Guideways;

Filing Info

• Accession Number: 00780334
• Record Type: Publication
• Report/Paper Numbers: FHWA/OH-99/006,, Final Report
• Contract Numbers: State Job No. 14561(0)
• Files: NTL, TRIS, ATRI, USDOT, STATEDOT
• Created Date: Dec 28 1999 12:00AM