Ionic Stabilization Performance in Expansive Clay and Selection of an Effective Test for Assessing Stabilizer Efficiency

This study investigated how a sulfuric acid–based ionic stabilizer interacted with expansive clay soils from Texas, and identified practical methods for evaluating treatment effectiveness. A combination of physical, mineralogical, and chemical tests was conducted to understand the stabilizer’s mechanisms and performance. These analyses were used to determine the most reliable test methods for assessing treatment efficiency and selecting the optimal stabilizer-to-water ratio. This study evaluated three stabilizer concentrations (1:300, 1:150, and 1:50) to determine the optimal dosage for reducing soil swelling and to identify the most practical laboratory method for assessing ionic stabilizer performance. The results demonstrated that stabilizer effectiveness varies by soil type and concentration, underscoring the need for dosage optimization. Among all tests examined, the free swell test consistently reflected the stabilizer’s impact, and aligned more with trends observed in other physical, chemical, and microstructural analyses. Accordingly, this study identified free swell as the most reliable and practical test for selecting optimal ionic stabilizer dosage and for guiding field application.