LAYER COEFFICIENTS FOR NHDOT PAVEMENT MATERIALS

In 1992, the New Hampshire Department of Transportation (NHDOT) experimented with the use of reclaimed asphalt concrete as a base course material, identified by NHDOT as reclaimed stabilized base (RSB). The RSB and a control test section were placed on Interstate 93 between exits 18 and 19. The RSB test section was designed to the same structural number (SN) as the control. To evaluate the structural capacity of these test sections, the U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) conducted deflection tests using a Dynatest 8000 falling weight deflectometer (FWD). Preliminary analysis of the results by NHDOT personnel showed higher deflections in the reclaimed asphalt concrete test sections. The explanation was that the layer coefficient used for the RSB layer in the design was probably incorrect. A total of 10 test sections constituting the base course materials used by NHDOT were built near Bow, New Hampshire. CRREL evaluated and estimated the layer coefficients of the base course materials. The test program was developed to characterize the material in more than one way. Tests were conducted with the heavy weight deflectometer (HWD), dynamic cone penetrometer (DCP) and the Clegg hammer. In-situ California bearing ratio (CBR) tests were also conducted. The deflections from the HWD were used with the WESDEF backcalculation program to determine the layer moduli. The moduli were then used with the AASHTO Design Guide to calculate the layer coefficients. The layer coefficients were also determined with the method proposed by Rohde. The CBR values from the Clegg hammer, in-situ CBR, and DCP tests were also used in the relationships in the HDM model to determine the layer coefficients.

Language

  • English

Media Info

  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 53 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00670383
  • Record Type: Publication
  • Report/Paper Numbers: Special Report 94-30
  • Files: TRIS, USDOT, STATEDOT
  • Created Date: Dec 6 1994 12:00AM