This study consisted of an evaluation of self-hardening fly ash (Class C) used as an additive in the treatment of shoulders surfaced with sand clay gravel and/or shell (oyster). This was accomplished through construction of fly ash treated aggregate should test sections at four sites in two phases. In the first phase test sections were constructed with fly ash from two sources. In the second phase fly ash from two new sources, as well as portland cement, was used to treat existing shoulders. Periodic visual condition surveys were conducted over a four-year period for test sections constructed in the first phase and over two years for those constructed in the second phase. Deflection measurements were also taken at selected time intervals. Based on visual condition surveys, the physical condition and performance of the sand clay gravel treated test sections were equally good for all levels and types of additives, as well as sources of fly ash. Defelction measurements indicated approximately the same level of stiffness in the fly ash treated sections as was measured in the 6 percent portland cement treated sections at one year, with the latter measurements experiencing no additional increase after one year. The deflection measurements of fly ash sections at site 3 did not indicate any appreciable increase in stiffness level after one year. The physical condition of all shoulder sections containing shell stabilized fly ash or portland cement was judged only fair after two years. The deflection measurement for these sections indicated a decrease in SNs from that of preconstruction. The cause for poor results in all test sections at site 4 was not determined.

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 58 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00453747
  • Record Type: Publication
  • Report/Paper Numbers: FHWA-LA-85-177
  • Contract Numbers: 81-1S
  • Created Date: Jul 31 1988 12:00AM