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 $G_{\max }$ and material damping $D_{\min }$ 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 ${\gamma }_{\mathrm{th}}$ for each treatment method, and to study the effects of torsional shearing on the rate of degradation of normalized modulus $G/G_{\max }$ 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 ${\gamma }_{d-\max }$ on the wet side of Proctor optimum.