Alternative Approach to Clay Stabilization Using Granite and Dolerite Dusts

This paper describes the results of an investigation on the effect of two readily-available materials, namely granite and dolerite dusts on the properties of a tropical expansive soil from southeast Nigeria. The aim was to evaluate their use as potential stabilizing agents. Standard compaction, California bearing ratio (CBR), and Atterberg limit tests were performed on the natural expansive soil and on samples treated with varying percentages of granite or dolerite dust. Noticeable reduction in shrinkage and plasticity as well as an increase in CBR were observed in the treated soil samples. The improved clayey soil measured up to the Nigerian standards for materials used in general filling, embankment and sub-base materials, but they fall below the standards set for use as base materials. Based on the strength development, it seems that the cheap rock-dusts can be used as partial replacement for the other more expensive materials been used in treatment of expansive soils. Therefore their use may not only become an efficient method for the utilization of materials that are abundant in the terrain, but may also contribute to the development of the nation’s solid minerals sector.