Expansive clay soils—those that change significantly in volume with changes in water content—are the cause of distortions to structures that cost taxpayers several billion dollars annually in the United States. Much has been learned about their behavior over the past 60 years, and relatively successful methods have been developed to modify and stabilize them. This paper reviews some of the key advances developed over the past 60 years in improving our understanding of the nature and methods of modifying and stabilizing expansive clay soils. The state of the practice in stabilization is presented, and practical and research needs to help improve the state of the practice are discussed.

Review of Stabilization of Clays and Expansive Soils in Pavements and Lightly Loaded Structures—History, Practice, and Future

Expansive clays exhibit a high potential for the volume change behavior when the soil moisture changes. The estimated annual cost of the damage to the facilities built on expansive clay in the United States exceeds 9 billion dollars. Because of the physicochemical nature of the expansive clay, the use of chemical agents to improve their engineering properties is common. This research investigated the effects of chemical agents on an expansive soil from Texas through a laboratory injection method. The agents used in this study included lime, potassium based agents, and a group of ionic agents. Swelling tests, chemical tests, and soil suction tests were used to evaluate the stabilizing effects of those chemical agents. The testing results indicated that potassium based stabilizer, is an effective stabilizing agent to control the swelling potential of the expansive clay. It can also be injected in the field to build a moisture barrier. The chemical tests on the injected Texas clay showed that the stabilizing mechanism of the ionic agents is possibly through the cations’ exchange and the increase of the cations’ concentrations in the soil pore water.

/pdf/effects-of-chemical-stabilizers-on-an-expansive-clay-3nqj8uef9q.pdf

J. R. Blacklock

Papers

Soil Treatment for Foundations on Expansive Clays