DEVELOPMENT OF AN IMPROVED OVERLAY DESIGN PROCEDURE FOR THE STATE OF ALASKA. VOLUME II: FINAL REPORT

The state of Alaska is currently developing a pavement management system for their road system. An important input to the system is the determination of flexible overlays based on the structural adequacy of the existing pavement. The current overlay procedure (the Asphalt Institute method) does not always show a need for overlays, despite the poor surface condition of the pavement and high traffic volumes. Therefore, an improved procedure that would consider not only traffic but also surface distress, the structural properties of the pavement, and, most importantly, the effects of a freezing and thawing of the base, subbase, and subgrade layers are needed. This report recommends two such methods for further consideration: a simplified mechanistic method using equations developed in Pennsylvania, and a mechanistic procedure employing a backcalculation computer program known as ELSDEF. The results of these analyses are compared with those of the Alphalt Institute procedure. It was determined that the Asphalt Institute procedure was inappropriate and underdesigned the overlay for the road sections. The Pennsylvania equations tended to be slightly more conservative than the mechanistic method using ELSDEF except for cases where the pavement fatigue life had been utilized completely by past traffic loads. It is recommended that Alaska utilize the mechanistic approach to design overlays and ELSDEF as the backcalculation procedure. The Pennsylvania equations can be used in those cases not requiring considerable accuracy.

• Record URL:
  • http://www.dot.state.ak.us/stwddes/research/assets/pdf/fhwa_ak_rd_88_06.pdf
• 
• Record URL:
  • https://rosap.ntl.bts.gov/view/dot/40628
• Corporate Authors:

  Oregon State University, Corvallis

  Department of Civil Engineering, Apperson Hall
  Corvallis, OR  United States  97331-2302

  Alaska Department of Transportation and Public Facilities

  2301 Peger Road
  Fairbanks, AK  United States  99701

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Yapp, M
  • Hicks, R G
  • Connor, B
• Publication Date: 1987-10

Media Info

• Media Type: Digital/other
• Pagination: 303 p.

Subject/Index Terms

• TRT Terms: Backcalculation; Computer programs; Design methods; Equations; Flexible pavements; Freeze thaw durability; Frigid regions; Overlays (Pavements); Pavement design
• Geographic Terms: Alaska
• Old TRIS Terms: Freezing thawing effects
• Subject Areas: Data and Information Technology; Design; Highways; Pavements; I22: Design of Pavements, Railways and Guideways;

Filing Info

• Accession Number: 00488295
• Record Type: Publication
• Source Agency: Alaska Department of Transportation and Public Facilities
• Report/Paper Numbers: FHWA-AK-RD-88-06, TRR 87-15
• Files: NTL, TRIS, USDOT, STATEDOT
• Created Date: Sep 30 1990 12:00AM