POTENTIALS OF CEMENT KILN DUST IN SUB-GRADE IMPROVEMENT

Abstract

The ever increasing cost of construction materials in Nigeria and other developing countries has created the need for research into locally and readily available materials and also on how to convert materials considered to be waste by-product such as cement kiln  dust (CKD)  for use in construction and soil improvement. To achieve this, soil samples collected from Sankwalla – Busiri road, Obanliku Cross River State classified as an A-2-7 soil on AASHTO classification were stabilized with 2-24 % cement kiln dust (CKD) by weight of the dry soil. The investigation includes evaluation of properties such as compaction, consistency limits and strength of the soil. The results obtained show that the increase in CKD content increases the Optimum moisture content (OMC) and a reduction in plasticity. There was also improvement in the California Bearing Ratio (CBR) and Unconfined Compressive strength (UCS) with increase in the CKD content. A predictive model was developed and found to reasonably predict the relationship between properties of soil and the proportion of CKD used. The coefficients of correlation were high showing a strong relationship between the measured and predicted values.  The study concluded that CKD can be used to improve the properties of soil for construction purposes and 24% was observed to yield maximum improvement for CBR and UCS.