Effect of some grinding aids on the grindability of Portland cement

Laboratory grinding tests were conducted in a small steel ball mill to investigate the effect of various grinding aids on the grindability of portland cement. The specific surface area of the ground products was used as a measure of the grindability. Burned clay with water, water calcium lignosulphonate, pitch, coal and black liquor ``sodium lignosulphonate{''} from paper industry were used as grinding aids. Coal and black liquor were found to be the most effective grinding aids. The increase of specific surface is about 14\% at addition of 0.4\% and the compressive strength increase was 6\% for those grinding aids.