Alternative Test Methods for Measuring Permeability of Asphalt Mixes

One of the primary assumptions in structural pavement design for conventional pavements is that a flexible (hot mix asphalt) pavement be impermeable. The basis for this design approach is to minimize moisture infiltration and thus maintain adequate support from the underlying unbound materials. A non-destructive method, such as permeability testing, also has the potential to partially characterize the HMA quality more timely than destructive methods, and not leave imperfections in a newly constructed pavement. The paper identifies the nominal maximum aggregate size (NMAS), the theoretical maximum specific gravity of the mixture (Gmm), and thickness of the pavement or core as statistically important factors influencing permeability and air voids. Three methods of permeability testing were identified as viable: the Kentucky Air Permeameter, the Karol-Warner Permeameter, and the NCAT Permeameter. This paper recommends utilizing an NCAT Permeameter for field testing as part of the quality assurance/quality control process. The specific criteria for using an NCAT Permeameter as part of a percent within limit specification is 1560X10-5cm/sec for the upper specification limit and 0 cm/sec for the lower specification limit. The paper identified the viability of using a Karol-Warner Permeameter as part of the mix design as it has a strong relationship to the NCAT Permeameter, which is not capable of testing gyratory compacted samples. A corresponding Karol-Warner Permeability criteria identified in this study is an upper specification limit of 530X10-5 cm/sec and 0 cm/sec for the lower specification criteria and results in an average permeability value of 265X10-5 cm/sec.

Language

  • English

Media Info

  • Media Type: DVD
  • Features: Figures; References; Tables;
  • Pagination: 14p
  • Monograph Title: TRB 89th Annual Meeting Compendium of Papers DVD

Subject/Index Terms

Filing Info

  • Accession Number: 01158057
  • Record Type: Publication
  • Report/Paper Numbers: 10-2594
  • Files: TRIS, TRB
  • Created Date: Jan 25 2010 11:15AM