The Effect of Dolomite Additive on Cement Hydration

The effect of dolomite on alite hydration was investigated in order to elucidate the effect of dolomite addition in cement hydration. The rate of heat evolution both in cement – dolomite and alite – dolomite system was taken as a starting point. Subsequently the chemical shrinkage, conductivity of liquid phase and rheological parameters of pastes were characterized. The observations of microstructure were carried out under SEM and the hydration degree of alite was determined by XRD. The accelerating effect of additive was proved. At low percentage dolomite plays a role of cement replacement; at higher dosage – the „dilution” effect can be observed. However, increasing dolomite content is accompanied by higher amount of hydration products, as a results of crystallization on the fine dolomite grains and better absorption of water. The hydration degree of alite increases as well.