In the summer of 1979, a hot mix recycling project was completed in the towns of Houlton and Littleton in the State of Maine. The project consisted of overlaying an existing old macadam pavement with 1 3/4 inches of Gradation "B", utilizing recycled material. This was covered with 1 1/4 inches off a new (Gradation "C") wearing course. In addition to the overlay work, several test sections were also constructed. These test sections contained various thicknesses and types of recycled thicknesses and types of recycled base pavement. A similar section using virgin mix was also constructed to provide a direct comparison. Recycled pavement was also used in few specified areas as a wearing course. The hot recycled mixture was produced using the Minnesota Heat Transfer Method. A Stan-Steel plant was modified to the extent that an additional cold feed bin and belt were used to place the recycled material directly onto the plant scales when desired. Laboratory design and field experimentation indicated that a 50-50 mixture could be attained. In this case, the 50 percent virgin material consisted of 335 percent 3/4 inch stone, 5 percent 1/2 inch stone, and 10 percent sand. The other 50 percent contained recycled material screened into one stockpile. AC-5 asphalt cement was used, of which aproximately 2.5 percent was added to the total batch. Statistical analysis indicated that a comparatively uniform recycled product was produced. The product had a Hveem stability of 39. The strength of the various sections was obtained by using a Benkelman Beam to measure deflections. A radius of curvature meter was also used. These data indicated that the pavement produced was structurally sufficient except for the section containing the 2 inches of base. This 2 inch section was known to be structurally deficient. A cost analysis of the comparative test sections indicated that the recycled section compared favorably to the conventional mixture section with a savings of $4.23 per square yard. If only recycled material was used as the base course with a new surface course, the savings were only $1.06 in favor of recycled material. Thus, greater savings were obtained when both courses were recycled materials. By specifying that a recycled mixture be used on this project, approximately 7,400 tons of new aggregate and nearly 390 tons of asphalt was "saved." The savings in asphalt cement alone based upon the August 1979 price of $113 per ton represented a savings of $44,070. (Author)

  • Corporate Authors:

    Maine Department of Transportation

    Materials and Research Division, Box 1208, Hogan Road
    Bangor, ME  United States  04402
  • Authors:
    • Rand, D W
  • Publication Date: 1980-3

Media Info

  • Features: Appendices; Figures; Tables;
  • Pagination: 54 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00316478
  • Record Type: Publication
  • Report/Paper Numbers: Proj No. 5-(20) Tech Paper
  • Created Date: Jan 19 1981 12:00AM