Influence of Clutch Disc Waste (Grinding Dust) on Portland Cement Hydration

This paper evaluates the effect of grinding dust (GD), a waste generated in the clutch disc finishing process, on Portland cement hydration. For this, pastes with additions of 5%, 10% and 15% GD, relative to cement weight, were molded and compared with a reference sample. Tests of setting time determination by Vicat needle, calorimetry, monitoring the ultrasonic pulse propagation velocity and mineralogical analysis (X-ray diffraction) in pastes with 1 day of hydration were carried out. It was observed that GD, due to the presence of copper, zinc and phenolic resin in its composition, is responsible for retarding cement hydration and thus increases the setting time and delays the evolution of heat release and pulse propagation velocity. However, the formation of new crystalline phases was not observed.