A portland cement clinker, a natural pozzolan, and a granulated blast furnace slag (GBFS) were used to obtain blended cements that contain 25% mineral additives. The natural pozzolan, which was softer, was more grindable and granulated blast furnace slag, which was harder, was less grindable than the clinker. Two of the cements produced were obtained by intergrinding and the other two were obtained by separate grinding and then blending. All of the blended cements and the control cement without any additive had the same fineness as 3500 +/- 100 cm(2)/g Blaine fineness. During grinding, energy consumption of the mill was recorded and a sample corresponding to each energy level as taken from the mill at regular intervals and particle size distribution was determined. Cements produced were compared for change in particle size distribution during grinding and 1-,2-, 7-, 28-, and 90-day compressive strengths points of view. Also, interactions between clinker and mineral additive portions of blended cements during intergrinding is highlighted. (C) 1999 Elsevier Science Ltd. All rights reserved.