Subgrade characterization for better ground improvement design

A current research conducted at the University of Texas at Arlington is focusing on quantification of clay minerals in the fine fraction of the soil. The main intent of this research is to identify the dominating clay minerals in the soils to design more durable chemical stabilization method for subgrade soils supporting pavements. Such design will either replace or complement the current plasticity index (PI) based design. This paper summarizes available clay mineral identification methodologies including a select group of gravimetric methods to determine potassium, cationic exchange capacity and specific surface area properties. These properties are then used to quantify and identify clay minerals in the soils. Two clayey soils were used in the experimental studies to illustrate the methods for determining the amounts of various clay minerals. Test results from these studies are presented in this paper. Copyright ASCE 2008.