The present study aims to determine and evaluate the applicability of an industrial bottom ash (CBA), supplied from Tuncbilek Power Station-Turkey, in concrete industry. In the laboratory experiments, the bottom ash was used up to 25% as a partial substitute for the Portland cement. In order to be able to reduce the unburned carbon content, CBA was treated by three different processes (particle size classification, heavy medium separation and electrostatic separation). Based on the obtained results, it was concluded that the addition of CBA up to 10% as a replacement material for Portland cement could improve the mechanical properties of concrete, and thus, could be used in the concrete industry. The effect of operating parameters on treatment processes has also been discussed in the paper. (C) 2007 Elsevier Ltd. All rights reserved.