A description is provided of the use of an additive including polycarboxylate ether and/or lignosulfonate as grinding aid in cement grinding for producing a cement, especially when fly ash and rock flour are used in the cement. The additive is preferably an aqueous additive. The use of the grinding aid in the production of the cement leads to improved processability of concrete or mortar produced from the cement. In particular, improved stiffening behavior, a reduced water requirement, or a reduced superplasticizer requirement for the mortar or concrete is obtained.