Use of class C fly ash for stabilization of fine-grained soil

Fine-grained soils may have undesired characteristics such as high swelling potential and low strength, thus requiring improvement. One of the stabilization methods involves the use of fly ash. Fly ash is a waste material obtained from burning coal in thermal power plants. The use of fly ash is encouraged as an alternative material for soil stabilization, due to its features such as pozzolanic properties and economic availability. This paper describes the results of an experimental study on stabilization of a clayey soil with fly ash. Unconfined compressive strength (UCS) and triaxial tests were carried out on samples of kaolinite mixed with class C fly ash at different percentages and cured for 1, 7, and 28 days, in order to study the effects of class C fly ash on the mechanical behaviour of the stabilized soil. The results showed that inclusion of fly ash significantly improves the strength characteristics of the soil. Curing time was also found to have a significant effect on improving the properties of the soil.