Rheological characterization of cement pastes with functional filler particles

Cement pastes were studied using conventional rheological methods. The effect of different types of functional fillers on the rheological properties and hydration rate of the pastes was analysed. The fillers were found to have varying chemistry and therefore surface properties. Porous titania particles raised the cohesive energy of the paste significantly already at low additions. Limestone particles raised the cohesive energy somewhat, but clearly less than titania. The zeta potential of the particles was found to somewhat affect the rheology. Reaction rates of the pastes were measured using oscillatory rheological measurement with constant amplitude and frequency. Titania particles were found to accelerate the hydration rate more than limestone particles. Of the limestone particles pure calcite increased the reaction rate more than dolomitic limestone. When the limestone particles were modified to provide C-S-H nucleation sites the cohesive energy was raised and the reaction rate was further increased.