COMPARISON OF WOOD ASH AND BAGASSE ASH SOIL STABILIZATION METHODS

With the increasing of population and the reduction of available land, more and more construction of buildings and other civil engineering structures have to be carried out on weak or soft soil. Owing to such soil of poor shear strength and high swelling & shrinkage, a great diversity of ground improvement techniques such as soil stabilization and reinforcement are employed to improve mechanical behavior of soil, thereby enhancing the reliability of construction. Expansive soil is one of the major soil deposits of Ethiopia. They exhibit high swelling and shrinking when exposed to changes in moisture content and hence have been found to be most troublesome from engineering considerations. Stabilization occurs when lime is added to expansive soil and a pozzolanic reaction takes place. The hydrated lime reacts with the clay particles and permanently transforms them into a strong cementations matrix. Expansive soil showing low to medium swelling potential from Addis Ababa was used for determining the basic properties of the soil. Changes in various soil properties such as Liquid limit, Plastic Limit, Maximum Dry Density, Optimum Moisture Content, and California Bearing Ratio were studied. Expansive Soil is a kind of high plastic clay. Because it has Strong hydrophilic mineral composition, its engineering prosperities embodies that its shape contracts under dehydrating, Inflation and softening under the influence of water and the strength attenuates. This is very difficult to construct in the region of expansive soil. In the region of seasonal frozen, as capillary water rising height is larger; it is prone to phenomenon of frost boil or thawing settlement. It has important meaning to improve hydrophilic and physical and mechanical properties of expansive soil for Slope stability of embankment and cutting of highway engineering and reducing the cost of investment. The paper discusses the engineering properties of expansive soil in Detail; expound some main methods of improving expansive soil with wood ash and bagasse ash, compare and analysis the mechanism and characteristics of the methods. The paper introduces preliminary testing methods of Expansive soil performance and prospects improved in the future