Volume 25, Issue 1 (March 2002)
Evaluation of a Modified Soluble Sulfate Determination Method for Fine-Grained Cohesive Soils
Soluble sulfate measurement in subgrade soils is an integral part of geotechnical investigations due primarily to sulfate-induced heave distress problems experienced by certain chemically treated sulfate soils. Sulfate measurements will assist engineers in the selection of appropriate soil stabilization methods in construction projects. There are no ASTM test methods that provide sulfate measurements in soils. Current methods including the University of Texas at Arlington (UTA) method, which are based on gravimetric procedures, often provide test results with high standard deviations. A modified UTA method, which was developed by addressing the limitations of the earlier methods, is presented in this paper. This procedure is evaluated for reproducible and reliable sulfate measurements in three artificial soils and one natural soil. The modified procedure provided reproducible sulfate measurements for all soils with coefficients of variations (COV) less than 10%. These results matched with ion chromatography measurements, which indicate that the modified method provided reliable measurements.