Five hot-mix asphalt projects have demonstrated the feasibility of lower temperatures in both mixing and laydown without any sacrifice in pavement quality. On each of the projects, regular- temperature mixes were put down alongside the low-temperature mixes so that comparisons could be made between the two types. Job sizes were in the 2,000-4,000-ton-range and conventional equipment was used. The study found that when aggregates and sands are dried at 230-240 deg. F. and tested in the hot (storage) bins, the moisture content is quite low even if the original stockpile materials are as high as 7.0 percent. Storage temperature of the asphalt varies from 250 deg. F to 325 deg. F. Very often asphalt is received at the plant at even higher temperatures. The asphalt heat contributes usually 5 to 7 percent of the heat to the final mix, so the temperature of the asphalt in the storage tank does not significantly change the aggregate or mix temperature. Incomplete coating was found to be a minor problem. A fuel saving of about 0.5 gallon per ton of aggregate dried was noted. It was also found that the pavement must be rolled immediately after laydown, and that there was less hardening of the asphalt. Studies have been started on Marshall values obtained at 225 deg. and 275 deg. F mix and compaction temperatures.

  • Corporate Authors:

    National Asphalt Pavement Association (NAPA)

    5100 Forbes Boulevard
    Lanham, Maryland  United States  20706
  • Publication Date: 1976-6

Media Info

  • Features: Photos; Tables;
  • Pagination: p. 9-10
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00141252
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Oct 26 1976 12:00AM