Soft clay is a problematic soil due to its low bearing capacity and high settlement. To treat such soil, many techniques were developed, such as a replacement method with sand bed, stone columns, sand columns, vertical sand drains…. etc. The main objective of this study is to investigate the effect of the introduction of slag-cement dust columns to soft clay on the consolidation parameters such as coefficient of consolidation, compression index, and compressibility index. Three consolidation tests were carried out on three soft clay samples. The first sample was soft clay without treatment. The second sample was soft clay treated with one slag-cement dust column, and the third sample was treated with three slag-cement dust columns. All Samples were tested in a Modified Consolidation Apparatus. A relationship between void ratio and stress was deduced. The tests showed that the columns increased the clay consolidation rate and decreased the compression index, where the columns absorbed the clay water content. The consolidation coefficient values for the treated clay soil proved that Han's model applies to clay treated with slag-cement dust columns (SCCs).