Rheological properties of belite cement pastes

Results of rheological examination of belite cement pastes prepared from clinkers containing various crystalline modifications of the C₃A phase are presented. Pastes obtained from be lite cements of comparable C₃A contents, prepared from clinkers containing potassium only and both potassium and sodium but no sulphates, have higher plastic viscosity and yield values at the initial stage of hydration than those prepared from alkali-free clinkers. The highest plastic viscosity and yield values are shown by pastes in which the C₃A phase has a prismatic morphology. Although C₃A type has a marked effect on the rheological properties of cement pastes, it is much less important than the specific surface area of the ground clinker and the waterlcement ratio of the paste.