More than 50 changes to four Superpave mix design standards were approved by the states in February 1999. A relaxed criterion of density at the initial number of gyrations (N-initial) for the gyratory compactor will allow the use of more finely graded mix designs for low-volume roads. The table for determining the number of gyrations a mix must undergo in testing (N-design table) has been greatly simplified. Mixture aging procedures have been modified for both time and temperature. Pavement layers are defined more precisely. Clarifications have been made to the table that is used to tell how an asphalt binder's high-temperature grade can be "bumped up," depending on the speed or volume of traffic. The determination of mixture properties are now calculated directly on the mixture at the N-design level instead of being back-calculated from the N maximum level. The net effect of the changes is an improved and more practical mix design system.

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  • Corporate Authors:

    Scranton Gillette Communications

    380 E Northwest Highway, Suite 200
    Des Planes, IL  United States  60016-2282
  • Authors:
    • Bukowski, J
  • Publication Date: 1999-12


  • English

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Filing Info

  • Accession Number: 00781842
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jan 31 2000 12:00AM