Strength Characterstics of Stabilized Embankment Using Fly Ash

Abstract

Infrastructure projects such as highways, railways, water reservoirs, reclamation etc. requires earth material in very large quantity. In urban areas, borrow earth is not easily available which has to be hauled from a long distance. Quite often, large areas are covered with highly plastic and expansive soil, which is not suitable for such purpose. Extensive laboratory / field trials have been carried out by various researchers and have shown promising results for application of such expansive soil after stabilization with additives such as sand, silt, lime, fly ash, etc. As fly ash is freely available, for projects in the vicinity of a Thermal Power Plants, it can be used for stabilization of expansive soils for various uses. The present paper describes a study carried out to check the improvements in the properties of expansive soil with fly ash in varying percentages. Laboratory tests like 1) grain size analysis 2) atterberg limits 3) standard compaction 4) permeability test have been carried out on soil and CBR (California bearing ratio) test is conducted on soil sample mixed with fly ash in various proportions and results are reported in this paper. One of the major difficulties in field application is thorough mixing of the two materials (expansive soil and fly ash) in required proportion to form a homogeneous mass. The fly ash is mixed with soil in required proportion until the CBR value for the embankment is achieved.