Study of rheological parameters of cement pastes from Portland cement CEM I

The rheological properties of the pastes from rapid hardening cements CEM I, of all strength classes and in the case of different cement to water ratios. The experimental results have shown that with the w/c ratio increase, in the case of all cement pastes, the decrease of plastic viscosity, in the range of share rates. The Herschel-Bulkley's parameters underwent the following changes. The yield stress value tau(0) in the case of all pastes is decreasing with the decrease of w/c ratio. The stiffness coefficient k is decreasing for the paste of cement 52.5R, but the paste from 42.5R practically has no change and the paste of 32.5R shows weak correlation and is undergoing different changes. The structural number n is decreasing for the paste of cement 32.5R with w/c ratio increase, and for remaining pastes show different changes with weak correlation. The flow curves of cement pastes are showing the high dependence on strength class, which is probably caused by cement fineness increasing with cement class development.