Evaluation of Stabilization of Sulfate Soils in Texas

This implementation project was developed to provide technical support to the Texas Department of Transportation (TxDOT) in developing subgrade soil mixture designs in high sulfate soils and to monitor the performance of projects constructed following the guidelines established in Project 4240. Secondly, the researchers were to assess equipment needs of the TxDOT districts, train laboratory personnel in mix design procedures in high sulfate soils, and provide educational materials for TxDOT to train additional personnel. Mix designs of high sulfate soils for two projects, in the Austin and Laredo Districts, are reported as technical support to districts. The construction and subsequent reevaluation of the project in Eagle Pass is reported to give TxDOT a record of the construction process used in the high sulfate soil on the Second Street project and shows how the project has performed since construction. Evaluation of the 3-D swell procedure shows the test to be repeatable if the density and water source are tightly controlled. A review of the equipment needed for adequate testing of the high sulfate subgrade soils showed that all required equipment can be obtained at minimal cost to TxDOT.