A LABORATORY INVESTIGATION ON THE EFFICIENCY OF EXPANSIVE SOIL TREATED WITH SAWDUST ASH AND SODIUM HYDROXIDE AS FOUNDATION BED

Abstract

India has large tracts of expansive soils commonly known as black cotton soils which covers approximately 20% of the total land area of our country. These soils experience large volume changes on exposure to climates with alternate wetting and drying. Several innovative foundation techniques have been suggested to overcome the problem of expansive soils. Those techniques include sand cushion technique, cohesive non-swelling (CNS) layer technique and under reamed piles. Stabilization of expansive soil with various types of additives is the most commonly used technique. Stabilization is process of fundamentally changing the chemical properties of soft soils by adding stabilizers or binders, either in wet or dry conditions to increase the strength and stiffness of the naturally weak soils. In present investigation, the aim is to reduce swelling and shrinkage behaviour of expansive soil by improving strength and engineering properties of soil. Also, the industrial solid waste Sawdust ash is utilised for stabilisation so as to solve the problem of indiscriminate disposal. The other additive used in this study is Sodiumhydroxide. Various tests are conducted with varying proportions and results are reported.