Influences of micropowder gradation on rheological properties of cement-based composite pastes

The rheological parameters of cement pastes were investigated by varying the type and content of micropowders and the ratio of water to binder. Compressible packing model was used to calculate the packing density and to evaluate the influence of micropowders gradation on the rheological properties of fresh cement pastes. Results indicate that the higher the packing density is, the lower the yielding shear stress and plastic viscosity will be. When the ratio of water to binder is less than 0.20, the cement paste with 15% UFA and 15% SF has highest packing density and lowest yielding shear stress and plastic viscosity, which is beneficial to the workability of ultra-high performance concrete.