Several asphalt technology advances were initiated by Metro Transportation in 1994: high stability (HS) hot mix incorporating RAP; large stone binder course (LSBC) in a deep strength pavement; stone mastic asphalt (SMA) on a major route; and performance graded asphalt binders. While incorporating RAP in Ontario heavy duty binder course is not conventional practice, the metro practical experience with a replacement limit of 10 percent has been satisfactory. The use of LSBC (dense-graded, minus 37.5 mm, crushed aggregates) has proven favourable in terms of stability and durability for arterial roads, along with ease of placement. The use of SMA extends Ontario experience and clearly demonstrated the durability, frictional, stability and fatigue advantages of SMA over conventional surface course mixes. Performance graded binders (PG 64-28, with specification and testing to AASHTO interim standards) were assessed during cool, late season 1994 paving, and PG 70-28 is being used selectively during 1995 based on SHRP and applied Metro experience. The resilient moduli, fatigue endurance, and resistance to rutting of HL 8 (HS, 10% RAP), LSBC, SMA and HL 1 (PG 64-28) have been determined in the Nottingham Asphalt Tester (NAT), and these mixes shown to have significantly enhanced potential performance. For the covering abstract of this conference, see IRRD number 872672. (A)


  • English

Media Info

  • Pagination: p. 18-37

Subject/Index Terms

Filing Info

  • Accession Number: 00726394
  • Record Type: Publication
  • Source Agency: Transportation Association of Canada (TAC)
  • ISBN: 0-921317-56-5
  • Files: ITRD
  • Created Date: Oct 28 1996 12:00AM