EVALUATION OF ENGINEERING PROPERTIES OF A FAT CLAY SOIL MIXED WITH AGGREGATE DUST (A CASE OF GUBRE FAT CLAY SOIL)

Abstract

Fat clay soils are soils of more percentage of clay especially more than 50% in a given soil sample such soils are one of the problematic soils which are easily compressible and are not used as a construction material. Compressibility is one of the properties of a fat clay soil and it is the degree to which a soil mass decreases in volume when supporting a load. This research aimed at evaluating the compressibility nature of fat clay soil after stabilizing with aggregate dust and intern this stabilized soil material is used as a sub grade material or as a fill material in building construction. The lab work involves sieve analysis along the consistence test to classify the soil samples. The preliminary investigation of the soil shows that it belongs to A-7-6 class of soil in AASHTO & CH in USCS. Soils under this class were poor for sub grade construction. Atterberg limit, compaction and CBR test were used to evaluate the properties of stabilized soil. The soil stabilized with the aggregate dust is mixed in stepped that 0, 5, 10, 20 & 30% by dry mass of soil. The analysis of the result shows the addition of aggregate dust improve the geotechnical properties of soil. The addition of aggregate dust reduces PI, Swelling and the optimum moisture content with an increase in MDD and CBR with an increase of aggregate dust. The mixture of this fat clay soil and aggregate dust are used as raw material after mechanical stabilization, in many earthworks applications. Such as a fill material in the construction of road way shoulder and at the parking lot etc The clay content, the amount and size of aggregate dust, are known to affect the compressibility potential, and thus, the stiffness of the soil when subjected to vertical loads.