Stabilization Of Expansive Soils By Steel Slag, Case Of Expansive Clay Soil In Addis Ababa

Abstract

Investigation of industrial waste by products as geo material over the ordinary and market oriented stabilizers has both economic and environmental significance. Steel slag is one of the waste products which is investigated in this as geo material for stabilization in this study. This research is aimed at evaluating the suitability of steel slag for stabilization of expansive soils. The laboratory investigations involved Atterberg limit tests and grain size distributions for classifying the fine grained soils. Accordingly, the investigation of the untreated soil belongs to A -7-6 class of soil in the AASHTO classification system and CH in the USCS with very poor strength. Atterberg limits, compaction, free swell, specific gravity, CBR and UCS tests were used to evaluate properties of the stabilized soil. The soil was stabilized with varied proportions of steel slag like 3%, 5%, 7% and 9% by dry weight of the soil. The treated soil samples for UCS, Atterberg limits and CBR were also cured for 3 and 7 days both in desiccator and none permeable hard plastic at room temperature respectively. The optimum steel slag required for stabilizing the expansive soil was determined based on strength values of moisture density relation, UCS and soaked CBR which is obtained as 7%. Analysis of the test result indicates an improvement in engineering properties of steel slag stabilized soils and liquid limit, plastic limit, plasticity index, OMC and free swell slightly reduced. As the amount of steel slag increases, all the engineering properties of the treated soil (UCS, MDD and CBR) also increase until the optimum amount of the stabilizer.