DEMONSTRATION PROJECT NUMBER 59, THE USE OF FLY ASH IN HIGHWAY CONSTRUCTION, SCOTT COUNTY, TENNESSEE

This report describes the laboratory and construction procedures together with preliminary roadway tests for a limestone aggregate base, stabilized with hydrated lime and fly ash. A flexible pavement of 6.25 inches in depth was placed on the lime--fly ash aggregate (LFA) material. Laboratory tests were conducted on the fly ash and hydrated lime to insure material quality and to determine the suitability and compatability of the combined materials. The mix design for the LFA material consisted of 3.5% lime, 11.0% fly ash and 85.5% "crusher run" limestone aggregate with approximately 8% water in order to bring the mixture to optimum moisture. Twenty-eight (28) day laboratory specimens cured at 100 deg F had compressive strenghts up to 2,032 psi. The materials were mixed in an asphalt batch plant and hauled twenty-five (25) miles to the jobsite. Production rates averaged 1200 tons/day with approximately 13,000 tons of LFA material being placed. Field densities ranged from 135.5 pcf to 143.6 pcf, exceeding laboratory densities by at least 100%. Too much moisture in the material tended to lower densities and the surface became quite "spongy"; however, in a few days an increase in density was noticed. A cost of $4.51 per square yard was calculated for the material. Compressive strengths of cores obtained at 6 months broke an average of 2,100 psi. Deflections taken with the Benkelman Beam were .0065 and .007 inch. (Author)

Media Info

  • Features: Appendices; Figures; Tables;
  • Pagination: 45 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00390271
  • Record Type: Publication
  • Report/Paper Numbers: FHWA-DP-59-1
  • Files: TRIS, USDOT, STATEDOT
  • Created Date: Dec 30 1984 12:00AM