Novel Stabilization Methods For Sulfate And Non-sulfate Soils

Expansive soils are commonly found in arid and semi-arid climate zone. These soils typically exhibit moderate to high plasticity, low to moderate strength, and high swell and shrinkage characteristic which in turn result in more swelling problems when the soil absorbs water. Both low strength characteristic and volumetric movements weaken the subgrade soils that they may lead to structural distress on road pavements. This research project was conducted at the City of Arlington, Texas. Soils in Arlington are known to be highly expansive. The expansive soils consist of both sulfate-rich soils and non-sulfate soils. This research project was conducted to assess the performance of novel stabilization methods in the field conditions in order to select an ideal stabilization method or methods for stabilizing expansive soils to minimize sulfate induced heave distress in Arlington, Texas. Laboratory testing programs were designed to assess the properties relating to volume change behavior of expansive soil samples taken from the City of Arlington, Texas. The experimental programs included basic soil property tests, chemical and mineralogy tests, and strength improvement assessments on the soils.Field monitoring was also conducted through instrumentation studies, elevation surveys, Dynamic Cone Penetrometer tests (DCP) and visual field inspection, to monitor the performance of pavements built over the stabilized expansive subgrade soils. Site investigation with an array of sensors and appropriate data acquisition in pavement instrumentation provides valuable data that are utilized to assess the performance of pavement layers in real field conditions. Life cycle cost analyses (LCCA) were also performed on both stabilized sulfate and non-sulfate soils. The field studies, laboratory studies, LCCA and Finite Element Modeling are used to develop design guidelines on the selection and construction of stabilizer treated subgrades for supporting pavements in sulfate rich and non-sulfate soil environments.