SOLID WASTE IN HIGHWAY CONSTRUCTION

The use has been demonstrated of mixtures of three power plant wastes (flyash, bottom ash and calcium sulphate) in paving parking areas. The parking area of Dulles International Airport, Washington, D.C. was paved with 5 inches of a compacted mixture of sulfate, lime, fly ash and aggregate on a compacted subgrade. About 75,000 tons of this mixture was placed at the rate of 1,000 tons per acre. The areas to be used for passenger car parking were given a bituminous seal primarily to retain poisture for curing, but which also served as the final surface. Two inches of conventional bituminous concrete was used to surface traffic lanes and bus parking areas. Details are given of the materials used as well as the construction procedures. The processing is also discussed of incinerator residue through grinding, further ignition and fusion to form a slag-type aggretate. A research and development process is described which involves a stepwise approach to effecting the fusion of incinerator residue and together with the minimal use of supplemental thermal energy. The 4 sequential steps are: reduce the residue particle size to minus 1/4 inch by hammer milling; burn out remaining combustibles in a rotary kiln while simutaneously permitting all noncombustible particles to heat up to 1600 deg F; fuse the noncombustible particles by permitting them to fall from the kilm into a pile that is heated to a relatively mild temperature of 2000 deg F where low melting gasses and oxides envelop unmelted high melting metals and oxides; cool the fused matrix at a controlled rate as it flows from the fusion furnace and is picked up on a moving grate conveyor leading to a crusher. Another approach to using incinerator residue is also outlined. Laboratory work indicates that satisfactory bituminous mixtures can be made with reside as the major portion of the aggregate, and field application of such mixtures used in black base construction has been made. Economic considerations however, pose a serious deterrant to the use of waste products in highway construction.

Media Info

  • Pagination: p. 12-14
  • Serial:
    • APWA Reporter
    • Volume: 42
    • Issue Number: 6
    • Publisher: American Public Works Association
    • ISSN: 0092-4873

Subject/Index Terms

Filing Info

  • Accession Number: 00098477
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 30 1975 12:00AM