At the present time, 34 power plants produce approximately 4000000 t of fly ash per year. Fly ash can be combined with lime to form a binder which sets in the presence of water. The composition of a subbase would be: 91% fly ash, 4% quick lime, 5% industrial gypsum (phosphogypsum). This mixture has a compressive strength of 30 bars at 7 days and 140 bars after one year. When manufactured in a plant, it is compacted with pneumatic-tyred rollers. The composition of a roadbase would be: 0/20 gravel (85%), 12% fly ash, 3% hydrated lime. The grading curve of gravel-ash mixtures is a bolomey curve. The composition of the binder (lime/fly ash = 1/4) is that giving optimum performance, the optimum proportioning being 15%. After one year, gravel-ash mixtures containing some limestone, have the highest strength, approximately 300 bars; with quartzite or siliceous limestone, the strength reaches 250 bars. These values decrease by approximately 16% when the density decreases from 100 to 95% of the optimum density. These gravel-ash mixtures are produced exclusively in mixing plants. Compaction is carried out by means of a heavy vibrating roller followed by a pneumatic-tyred roller. /TRRL/

  • Supplemental Notes:
    • This report was presented at the International Symposium on Slags, Cinders, and By-Products, Mons (Belgium), September 101-12, 1975.
  • Corporate Authors:

    Laboratoire Central des Ponts et Chausees (LCPC)

    Boulevard Lefebvre 58
    Paris Cedex 15,   France  F-75732
  • Authors:
    • Andrieux, P
    • Colombel, J H
  • Publication Date: 1976-5-6


  • French

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00152820
  • Record Type: Publication
  • Source Agency: Central Laboratory of Bridges & Highways, France
  • Report/Paper Numbers: Analytic
  • Files: ITRD, TRIS
  • Created Date: Jul 2 1977 12:00AM