Evaluation of sulfate-resistant and ordinary Portland cements for effective stabilization of natural sulfate-rich subgrades

Sulfate rich subgrade soils are present in southern, western and southwestern states in the U.S. Performance of highway and runway pavements are affected by the sulfate induced heave distress caused by the subgrades treated with calcium-based stabilizers. In the present research, the effectiveness of sulfate resistant and ordinary portland cement stabilizers were evaluated in order to determine their effectiveness in treating control soils containing various amounts of sulfates. Experiments were designed and conducted to identify moisture content and unit weight relationships, Atterberg limits, linear shrinkage, free swell strain behaviors, and unconfined compressive strength and resilient modulus variations with respect to cement treatment methods. Two curing periods, fourteen days and ninety days were investigated in this research. This thesis will present a comprehensive summary of these test results. Test results were used to evaluate the potential of sulfate resistant and ordinary portland cement stabilization methods to enhance strength and stiffness properties as well as to reduce swell and shrinkage potentials of natural sulfate rich soils.