Strength properties of fly ash stabilized clay soil

Abstract

Soil stabilization refers to the process of changing soil properties to improve strength and durability. Stabilization is the process of blending and mixing materials with a soil to improve certain properties of the soil. The process may include the blending of soils to achieve a desired gradation or the mixing of commercially available additives that may alter the gradation, texture or plasticity, or act as a binder for cementation of the soil. Additive stabilization is achieved by the addition of proper percentages of fly ash, cement, lime, or combinations of these materials to the soil. For this thesis soil mixed with fly ash and the quantities of fly ash added with clay soil which is 5%, 10% and 15%. Fly ash is classified according to the type of coal from which the ash was derived. Class C fly ash is derived from the burning of lignite or sub bituminous coal and is often referred to as “high lime” ash because it contains a high percentage of lime. Class C fly ash is self-reactive or cementitious in the presence of water. The selection of type and determination of the percentage of additive to be used is dependent upon the soil classification and the degree of improvement in soil quality desired. Generally, soil strength is a complicated geotechnical concept to simplify due to the inherent complexities of different soil types. Frictional strength, cohesive strength, and pore water pressure relationships are all integral to the effective strength determination of a soil but are only easily identified in the most select granular materials. The result of experimental show the strength of soil is increasing when increased percentage of fly ash. The best value of percentage is 15% after carrying out the experiment such as Atteberg Limit, Compaction, Unconfined Compressive and CBR Test. As a conclusion, soil stabilization is used to increase the bearing capacity of soils, for example when building embankments because fly ash is one such material with the potential to work well as a binding agent