Dynamic Properties of Chemically Stabilized Sulfate Rich Clay

A series of resonant column tests was conducted on chemically stabilized specimens of sulfate-rich expansive clay from southeast Arlington, Tex. Specimens were tested for different stabilizer types, stabilizer dosages, compaction moisture contents, and confining pressures. Three chemical stabilization methods were used: sulfate resistant type V cement, low calcium class F fly ash, and lime mixed with polypropylene fibers. Results in the small-shear strain amplitude range (<0.0001%) were analyzed to assess the influence of compaction moisture content and confining pressure on the linear shear modulus Gmax and material damping Dmin of stabilized soil. Tests were also conducted at small- to mid-shear strain amplitude levels (0.0001–0.01%) to assess the threshold strain limit γth for each treatment method, and to study the effects of torsional shearing on the rate of degradation of normalized modulus G/Gmax of treated soil. A 10%-by-weight dosage of sulfate resistant type V cement was found to give the highest modulus and lowest damping when compacted at 95% of maximum dry unit weight γd-max on the wet side of Proctor optimum.