Structural Design of Sulfur-Modified Warm-Mix Asphalt

It has been well documented that flexible pavement material stiffness significantly influences fatigue cracking and rutting performance. Therefore, choosing high-modulus asphalt concrete has the potential to increase the overall life of the pavement. One such material, sulfur-modified asphalt concrete, stems from 1970s sulfur-extended asphalt (SEA) technology in which hot liquid sulfur replaced a fraction of the asphalt binder. Recently, the SEA technology has been improved; sulfur pellets and warm-mix asphalt (WMA) additives are introduced into the mixing drum to produce sulfur-modified WMA, thereby eliminating the use of hot liquid sulfur, reducing production temperatures and fume emissions. Benefits also include the improvement of the pavement performance, structurally. Based on the laboratory experiment, dynamic modulus testing of four sulfur-modified WMA mixtures resulted in an overall increase in the stiffness relative to three control hot-mix asphalt mixtures, with significant improvements observed at high temperatures. Beam fatigue testing of these laboratory mixtures generated fatigue performance curves, indicating slightly shorter fatigue lives for high strain levels relative to a control mixture. The Mechanistic-Empirical Pavement Design Guide was used to evaluate eight hypothetical cross-sections comprised of sulfur-modified WMA relative to a control section planned for further full-scale testing at the National Center for Asphalt Technology’s (NCAT) Test Track. This analysis predicted improvements in fatigue cracking and rutting in all eight sulfur-modified cross-sections over the control section. Additionally, it was found that among the sulfur modified mixes, increases in the amount of sulfur and the design air voids further improved predicted performance relative to the control cross-section.

Language

  • English

Media Info

  • Media Type: DVD
  • Features: Figures; References; Tables;
  • Pagination: 16p
  • Monograph Title: TRB 89th Annual Meeting Compendium of Papers DVD

Subject/Index Terms

Filing Info

  • Accession Number: 01155677
  • Record Type: Publication
  • Report/Paper Numbers: 10-3697
  • Files: TRIS, TRB
  • Created Date: Jan 25 2010 11:53AM