Strength characteristics of the stabilized boggy shale (79-09-2)

Abstract

In cooperation with the Oklahoma Department of Transportation and the Federal Highway Administration, U.S. Department of Transportation, a research project entitled "Field Application of the Stabilization of Oklahoma Shales" (ODOT Study 79-09-2, ORA 158-867) was undertaken on June 1, 1979 by the University of Oklahoma. Initially, the Boggy shale in Atoka County was selected to be field stabilized. Later on, however, and because of seasonal limitations imposed on construction this site was abandoned for another site west of Enid. The laboratory work envisioned in Phase I had progressed to the point that it was considered prudent to continue and complete this effort. This Progress Report No. 1 presents the findings of this laboratory work. The stabilizing agents used were 12% portland cement, 5% hydrated lime, and 25% fly ash. The curing conditions were 28 days moist curing at 70 F and 100 F, and two compaction conditions were employed: no delay and 2 hours delay. The effectiveness of stabilization was evaluated in terms of the shear strength parameters of cohesion and internal angle of friction determined through triaxial compressive and direct shear strength tests as well as plasticity. Cement stabilization imparted maximum strength gain into shale with lime and fly ash giving lower but adequate strengths. Higher temperatures, namely 110 F, increased the effectiveness of stabilization but delayed compaction tended to slightly decrease it.