Influence of gypsum fineness in the first hours of cement paste: Hydration kinetics and rheological behaviour

During the cement production process, gypsum and other additives are input in the clinker grinding and each component present different breakage characteristics. The final particles size depends of the difference of the grindability of their constituent. Thus, it is difficult to know precisely the effect of gypsum fineness in the hydration kinetics or rheological behaviour of the cement paste. Therefore, three gypsum particle size were analysed, classified as fine, medium, and coarse, as well as one clinker collected before grinding. The primary tests included heat flow by calorimetry, X-ray diffraction, and rotational rheometer. It was possible to evaluate how gypsum fineness altered the hydration kinetics in the first few hours and promoted different rheological behaviours from the clinker analysed.