Thirteen asphalt concrete pavements built in Pennsylvania were studied from September 1961 to March 1973. As a result of an extensive sampling and analysis program, considerable information has been gained on the durability of asphaltic pavement. Based on physical test data (penetration, viscosity, and ductility) and percentage of asphaltenes, all of the asphalts used in the various pavements hardened with time. The time of year when a pavement is sampled was shown to influence test results among and within test pavements. In experimental pavement studies all test pavements should be sampled at the same time of the year on an annual basis. Inasmuch as conditions appear to be more detrimental in summer than in winter, an additional 5 to 6 months of pavement life may be realized if the pavements are built in the fall rather than in the spring. This allows some pavement compaction to occur before the agents of asphalt hardening become active. The air void volume of an asphalt pavement has been shown to be a major factor in pavement durability and, with deterioration, the safety of those using the pavement. Based on construction results on experimental pavements, air void contents of Pennsylvania highway pavements are on the average to high. Multiple air void specifications should be replaced by a single number-10 percent of maximum theoretical. Field control must become somewhat continous and totally enforceable. Lower viscosity asphalts, greater field compaction and control, and greater selectivity in design are offered as means of fulfilling lower air void content specifications. The hardening of asphalts in the pug mill should be studied closely. Lower mixing temperatures and shorter mixing times in conjunction with lower viscosity asphalts should provide a paving viscosity similar to that now used but with lower initial hardness.

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 14-26
  • Monograph Title: Asphalt properties and performance
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00128538
  • Record Type: Publication
  • ISBN: 0309023998
  • Files: TRIS, TRB
  • Created Date: May 14 1976 12:00AM