ASPHALT BINDER HARDENING IN THE MICHIGAN TEST ROAD AFTER 18 YEARS OF SERVICE

Analysis of six binders used in a Michigan test road has given an indication of the mechanism of compositional change and resultant hardening occurring during service. All the binders show the same directional changes in composition, namely a decrease in naphthene aromatics, which convert to polar aromatics and in turn to asphaltenes. This conversion is more pronounced in the top 1/8-in. (3.2-mm) layer than in the underlying 1/4-in. (6.4-mm) layer. The mechanism proposed here clearly explains the increase in softening point, increase in hardness, and loss of ductility. Change in composition and physical properties also accounts for the slight but observable differences in the wear, weathering, and raveling qualities of the different sections. The Michigan test road and its overlays are still in service, although they show considerable reflection and joint cracking. Superficial judgment indicates that two of the test sections show more wear and weathering than the others. Although this is of technical interest, these differences are not large enough to permit quality judgment or selectivity between sources.

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 27-34
  • Monograph Title: Asphalt properties and performance
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00128539
  • Record Type: Publication
  • ISBN: 0309023998
  • Files: TRIS, TRB
  • Created Date: May 14 1976 12:00AM