RECYCLING OF ASPHALTIC CONCRETE

An asphalt mixing plant, called a Thermo-matic plant, has been developed to recycle old asphalt concrete, and, through the use of an additive, produce an asphalt concrete that is virtually indistinguishable from that made with newly refined asphalt. The system is now recycling up to 80 tons of old pavement per hour. The recycled pavement has a mix design that should prove better than that of pavement constructed using newly refined asphalt. In addition, oxidation of the recycled asphalt may prove less, as the catalytic activity of the aggregate will have been destroyed by age. Stripping problems can be reduced by selecting as raw material those pavements which have proved to be resistant to stripping after years of continued use. The Thermo-matic is designed so that the burner's gaseous combustion products are prevented from coming into direct contact with the hot mix prior to being vented to the atmosphere. Also, any vapor or "blue smoke" from mixing is routed back through the combustion chamber, insuring that even gaseous hydrocarbons will not escape unburned, and thus preventing air pollution. The Thermo-matic is fully automated with exclusive sensing devices at the downstream of the drum to automatically determine and control the correct feed proportions of recycle materials, new aggregate, and liquid asphalt to meet hot mix specifications. A cost comparison shows that an 800 TPD Thermo-matic can be operated from about 27 cents per ton less than a comparable pugmill (a 12% savings), while the 1600 TPD Thermo-matic can be operated for about 22 cents per ton less than a comparable pugmill (a 15% savings). The cost savings realized by recycling old pavement is even greater and, in addition, recycling leads to fuel savings. Additional energy savings occur with the requirement of less electricity than a conventional plant, and with fuel being saved by not trucking asphalt that would otherwise have to be used, and not crushing and hauling aggregate which would otherwise be needed.

  • Corporate Authors:

    RMI Systems

    1770 Industrial Road
    Las Vegas, NV  USA  89102
  • Publication Date: 0

Media Info

  • Features: Figures; Tables;
  • Pagination: 15 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00127572
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Dec 29 1975 12:00AM