Transverse cracking of full-depth asphalt concrete on expansive clay subgrade generally leads to a severe transverse ridging condition. Studies have shown that use of so-called "soft" asphalt in such pavements will delay the onset and lessen the extent of transverse cracking. However, these asphalts may be more susceptible to permanent deformation under traffic, especially so in warm weather. There is still uncertainty regarding this aspect of in-service performance of thick lifts of asphalt concrete made with soft asphalt. To compare performance of a full-depth asphalt concrete made with SC-6 "soft" asphalt with that of one made with standard AC-6 asphalt, a 2.21 km test section was constructed in 1973 on Highway 15 east of Milden. Periodic measurements of transverse cracking, rut formation, peak deflection and radius of deflection basin, longitudinal and transverse profiles, and dynamic modulus were taken. Premature failure of both structues negated direct comparison of performance. Traffic was much heavier than design estimates and early shear failure resulted. The research aspect of the test section was thus abandoned at the end of 1977 after 48 months in service. At that time, the SC-6 section showed no transverse cracking whereas the AC-6 section had cracked frequently. This was the only significant difference in performance between the two asphalt concretes. /Author/

  • Corporate Authors:

    Saskatchewan Department of Highways and Transportation, Canada

    Government Administration Building
    Regina, Saskatchewan S4S OB1,   Canada 
  • Authors:
    • CULLEY, R W
  • Publication Date: 1978-7

Media Info

  • Features: Figures; Tables;
  • Pagination: n.p.

Subject/Index Terms

Filing Info

  • Accession Number: 00195411
  • Record Type: Publication
  • Report/Paper Numbers: Technical Report 27
  • Files: TRIS, ATRI
  • Created Date: Aug 15 1979 12:00AM