Geotechnics, Vol. 5, Pages 87: Long-Term Effects of Cement Kiln Dust (CKD) on the Permeability of a Treated Soil Slope
Geotechnics doi: 10.3390/geotechnics5040087
Authors:
Sandra A. A. O. Donkor
Mehrdad Razavi
Claudia Mara Dias Wilson
Benjamin Abankwa
Richard Otoo
Abraham Armah
Soil permeability is an important factor in the mining and geotechnical industry, impacting slope stability and tailings management. It directly influences the stability of structures, the control of water in tailings ponds, and the safety of workers. Various additives, such as cement kiln dust (CKD), bentonite, fly ash, polymers, lime, and asphalt, are incorporated into soil structures to improve permeability and stability. Any significant changes in soil permeability will alter the soil’s behavior. However, the long-term effect of most additives on structures remains unexplored. This study investigates the long-term impact of CKD on the permeability of a CKD-treated slope. The slope surface was treated with 0%, 5%, 10%, and 15% of CKD by the dry weight of the soil in 2008 and was evaluated in 2024. The permeability test results of the collected soil sample from the slope (2024) showed that the permeability of the soil decreases with an increase in the soil CKD content. The coefficient of permeability, k, is more than 100 times less for a CKD content of 15% by the dry weight of the soil compared to the permeability of the untreated native soil. The treated soil becomes almost impermeable when the CKD content increases to 20% (by the dry weight of the soil). However, the treated slope’s permeability increased over time, possibly due to erosion, resulting in a reduction in CKD content. The surface permeability of the slope exhibits an irregular distribution, resulting from the evolving spatial distribution of Cement Kiln Dust over time.