Rheological behavior of plasticized cement dispersed systems under vibration

Introduction. Obtaining self-compacting structural lightweight concretes (LWSCC) is an urgent scientific and practical task in the development of multifunctional building materials, where the main problem is to maintain un-iformity with high fluidity. Russian studies and studies from other countries have been devoted to this problem. The main focus was on prescription factors that affect the rheological and technological proper-ties of LWSCC. The content of components with different densities is the main difficulty of this develop-ment. Oscillation is one of the methods for estimating changes in the rheology of cement-mineral systems over time. Early studies of LWSCC on hollow microspheres showed changes in rheological properties with changes in the concentration of plasticizer, W/C ratio and the dispersion of the mineral aggregate. The next stage of research on the rheology and uniformity of LWSCC by the oscillation method is to es-tablish the influence of each component in a separate group of cement–mineral systems included in LWSCC. Methods and Materials. The object of research is cement-mineral systems from different combinations of components in a con-stant ratio of their mass parts, which make up LWSCC on hollow microspheres with an average density of 1400 kg/m3. The subject of the study is the rheological properties of such systems during oscillation. Plasticized and non-plasticized systems were compared. The following parameters were used to analyze the structure of the studied systems: the thickness of the water shell, the volume of cement dough, the thickness of the cement dough, and the grain spreading coefficient. Results and Discussion. The kinetics of the shear stress variation during oscillation is described by varying intensity, showing the transforma tion of the cement system structure over time. There is a noticeable difference between the changes in the rheological properties of cement pastes with and without plasticizer. The importance of the addition of micro-silica in the stabilization of the concrete mixture is emphasized. Conclusion. The water thickness (hw ) is a structural parameter that does not take into account the surface properties of dispersed phases and liquids in plasticized systems. The determination of the water consumption of LWSCC compo nents and the role of plasticizer in this is a promising direction for the development of the topic.