EFFECT OF END-POINT COMPACTION ON SUPERPAVE MIX DESIGNS

In the Superpave hot mix asphalt (HMA) mix design system, gyratory specimens are compacted to varying levels of initial (Ninitial), design (Ndesign) and maximum (Nmaximum) gyrations. Initially, in the Superpave system, specimens were compacted to Nmaximum and their volumetric properties backcalculated at Ndesign. However, there can be errors in the HMA volumetric properties at Ndesign, as a result of the backcalculation. This study was conducted to determine differences in volumetric properties and design asphalt content for commonly used HMA mixes in Mississippi. Forty-eight mixes were first designed by compacting directly to Ndesign. Afterwards specimens were compacted to Ndesign and Nmaximum at the determined design asphalt content. Volumetric properties of specimens compacted directly to Ndesign were compared to those backcalculated from Nmaximum. Additionally, the Corelok vacuum sealing procedure, along with the conventional water displacement technique, was used to determine the bulk specific gravity of all compacted specimens. An evaluation of the effect of the Corelok device on the mix design asphalt content and voids in mineral aggregate (VMA) was conducted. Differences in the volumetric properties, as a result of compacting specimens directly to Ndesign, will result in a reduction of 0.14% design asphalt content and 0.29% VMA. By using the Corelok device and compacting specimens directly to Ndesign overall average increases in the design asphalt content and VMA of 0.15% and 0.35%, respectively, were observed.

• Record URL:
  http://www.gomdot.com/Divisions/Highways/Resources/Research/pdf/Reports/InterimFinal/SS145.pdf
• 
• Record URL:
  https://rosap.ntl.bts.gov/view/dot/24142
• Corporate Authors:

  Mississippi State University, Mississippi State

  Department of Civil and Environmental Engineering
  Mississippi State, MS  United States  39762-9546

  Mississippi Department of Transportation

  401 North West Street, P.O. Box 1850
  Jackson, MS  United States  39215-1850

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • White, T D
  • Buchanan, M S
• Publication Date: 2003-1-10

Language

• English

Media Info

• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: 138 p.

Subject/Index Terms

• TRT Terms: Air voids; Asphalt content; Asphalt mixtures; Backcalculation; Compaction; Gyratory testing machines; Hot mix asphalt; Mix design; Superpave
• Uncontrolled Terms: Corelok device
• Subject Areas: Data and Information Technology; Highways; Materials; I31: Bituminous Binders and Materials;

Filing Info

• Accession Number: 00974806
• Record Type: Publication
• Report/Paper Numbers: FHWA/MS-DOT-RD-03-145,, Final Report
• Files: NTL, TRIS, USDOT, STATEDOT
• Created Date: Jun 3 2004 12:00AM