Determination of Ndesign for CIR Mixtures Using the Superpave Gyaratory Compactor

Cold in-place recycling (CIR) is a viable pavement rehabilitation technique that recycles 100% of the reclaimed asphalt pavement (RAP) in place, without the addition of heat. One of the barriers to wider use of CIR has been the lack of a suitable mixture design procedure. Researchers have shown that Superpave mix design technology is applicable to CIR mixtures if the Ndesign number of compaction gyrations can be established for the Superpave gyratory compactor (SGC). The objective of this project was to determine the mix design compactive effort (Ndesign) using the SGC required to match the field density of CIR mixtures. RAP from seven CIR projects was obtained, along with the emulsified asphalt cement from each project. Samples were compacted using the SGC with the mix water and emulsion content from the field. Samples were compacted immediately after mixing and after a 30, 60 and 120 minute initial cure time. The change in density with compaction gyrations was monitored, and the Ndesign number of gyrations required to match the field density was determined. The effect of initial cure time and RAP physical properties, such as gradation, percent flat and elongated particles, aggregate gradation and angularity on Ndesign, was evaluated. RAP shape, as measured by percent flaky pieces, was found to influence compacted field density. The Ndesign compactive effort for CIR mix design also was established.


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 82p

Subject/Index Terms

Filing Info

  • Accession Number: 01531727
  • Record Type: Publication
  • Files: TRIS, ATRI, USDOT
  • Created Date: Jul 18 2014 3:21PM