The addition of a small amount of paving grade asphalt cement to stabilize open-graded free draining aggregate was initially proposed in 1962 as a construction expedient. It was based on the results of laboratory permeability tests which revealed that it would not significantly reduce permeability and would provide a stable working platform for completion of the pavement structural section. Asphalt treated permeable material (ATPM) use since that time has proliferated as a result of the growing acceptance of positive rapid internal drainage as a means of extending pavement life. As of 1985, 10 states had used ATPM with 7 reporting "routine" application. By 1990, the number of user states had increased to 21 with another nine indicating plans to do so. ATPM is being placed in 3 to 6 in. lifts under both rigid and flexible pavements. Six states have or will place ATPM directly on the subgrade. All but 2 user states install pipe collector and outlet systems with ATPM. Five states assign a structural coefficient for ATPM corresponding to a stabilized base course. Eleven states give it no structural value while 10 assign a value equivalent to aggregate base. Results of recent research involving resilient modulus testing of ATPM indicate that assigning a structural coefficient for ATPM equivalent to a stabilized base is a valid assumption. A comparison of the cost of a conventional (undrained) pavement with those including an ATPM layer in lieu of aggregate base, revealed the possibility of significant life cycle cost savings by the substitution of an ATPM base for an aggregate base. Based upon the assumption of a 33% increase in pavement life due to its internal drainage feature, a life cycle cost analysis indicated a 12 to 22% savings for the drained pavement. The most commonly cited construction problem with respect to ATPM is its initial instability at elevated temperatures. User states have addressed this problem by requiring the use of crushed aggregate, stiffer (AC-20+) grades of asphalt cement and the control of rolling temperatures. A quarter of user states test ATPM for moisture susceptibility and use anti-strip additives.

  • Supplemental Notes:
    • Reprint issued again: 9/94.
  • Corporate Authors:

    National Asphalt Pavement Association (NAPA)

    5100 Forbes Boulevard
    Lanham, Maryland  United States  20706
  • Authors:
    • Forsyth, R A
  • Publication Date: 1991-4

Media Info

  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 32 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00611891
  • Record Type: Publication
  • Report/Paper Numbers: QIP 117
  • Files: TRIS
  • Created Date: Aug 31 1991 12:00AM