Evaluation of strength, swell and shrinkage characteristics of chemically treated soils from north Texas

Subgrade soils of north Texas are recognized as problematic soils since they exhibit low strength, high swell and shrinkage characteristics. These properties weaken the subgrades and cause severe damage to the pavements. Hence, in the present thesis, the strength, swell and shrinkage characteristics of an Arlington soil treated with four novel stabilization methods were evaluated. The four stabilizers studied in this research were Class F Fly Ash with Sulfate Resistant Cement, Ground Granulated Blast Furnace Slag, Sulfate Resistant cement and Combined Lime-Fibers. Experiments were designed to measure compaction moisture content and dry unit weight relationships, Atterberg Limits, linear shrinkage, free swell strain behaviors, and unconfined compressive strength properties. For treated soils, a curing period of 7 days was used.; Sulfate resistant cement (Type V) provided most effective treatment by improving shear strength and reducing the swell and shrinkage potentials of southeast Arlington soil. The class F fly ash with type V cement treatment provided the next best effective treatment of present soil. The GGBFS provided third best performance among the present stabilizers. Lime and fibers provided moderate improvements. Also, correlations for resilient moduli properties were developed for control and all four treated soils. These correlations use unconfined compression strength property, confining pressure and deviatoric stress conditions of subgrades.