Modifying Properties of Black-cotton Soil by Wood-ash

Abstract

Soil is a base of structure, which actually supports the structure from beneath and distributes the load effectively. If the stability of the soil is not adequate then failure of structure occurs in form of settlement, cracks etc. Expansive soil also known as black cotton soil is more responsible for such situations and this is due to presence of montmorillonite mineral in it, which has ability to undergo large swelling and shrinkage. To overcome this, properties of soil must be improved by artificial means known as ‘Soil Stabilization’. It is a technique which improvises one or more soil properties by mechanical, cementing and chemical use. Many research has been conducted for stabilization of soil by using cementing, chemical materials e.g. fly ash, cement, Calcium chloride, Sodium chloride etc. Most of Ethiopian population uses fire wood. Combustion of wood produces ash after burnt, the resultant ash is known as ‘Wood Ash’. It is a material that can be used to improve the existing properties of black cotton soil. In this study laboratory experiments were conducted on black cotton soil with partial replacement by Wood Ash (5%, 10%, and 15%). This paper highlights significant increase in properties of black cotton soil obtained at 10% replacement of Wood Ash without any chemical or cementing material.