Influence of clinker grinding-aids on the intrinsic characteristics of cements and on the behaviour of mortars

Abstract

In the production of portland cement, grinding aids are used to improve the grinding stage and reduce the energy required to achieve the required fineness. These additives remain in the final product and they might influence the characteristics and properties of the cement, and thus, mortar and concrets. This paper presents an evaluation of two grinding-aid additives used in the production of portland cement ground in a ball mill at a laboratory stage, with suitable proportions of portland cement clinker and gypsum. A control cement mix was also produced without using any admixture and the results are shown on a comparative basis. Conclusions indicate that grinding-aids additives have some influence on the characteristics of portland cement produced, increasing their specific surface and modifying microstructure and its packing ability. Mortars and concretes made with cements ground with the addition of gringing-aids exhibit higher strength at any age and a reduced water demand. Special attention should be taken to consider any interaction with water-reducing admixture in concretes and mortars.