OPTIMUM STABILIZATION REQUIREMENT OF IMO CLAYSHALE

Abstract

Clayshale is one of the problematic soils often encountered in civil engineering construction and is notable for its low shear strength when wet and rapid deterioration on exposure to weather.

The geo-technical and engineering properties of samples of Imo clayshale collected from Nsugbe Omo (along Onitsha - Nsukka road in the eastern part of Nigeria) were investigated. When the existing standards in civil engineering practice such as Road Note 29, Western Nigeria Road specification, Nigeria Board of Road Research Institute, (NBRRI), the soil proves highly inadequate for road construction from strength criteria. Also index properties suggest that the sample is a potentially high swelling clay.

In order to reduce the expansiveness of this sample and also increase the strength, stabilization by additives was employed. Cement, Lime and flyash were utilized at various percentages. Stabilized samples were tested in accordance with BS 1924 (1975).

It was observed that flyash stabilization Imo clayshale is inadequate for civil engineering construction both from strength criteria and index properties. It was also observed from the results that 8% lime, 15% lime, mixture of 6% lime and 8% flyash, and 15% cement are suitable for road construction on the basis of strength criterion.