Rheological properties of cement-based slurry and evaluation of rheological model: Influence of particle size and shape

With the continuous development of mineral admixtures and additives, the influence of various factors on the rheological properties of cement-based slurry remains unclear. In this study, the effects of particle size, particle shape, shear rate, and time on the rheological properties were analyzed. The rheological curves were determined using an RST-SST rheometer and fitted with the Bingham model, Modified Bingham model and Herschel-Bulkley model, respectively. The rheological parameters were evaluated. The results showed that the effect of particle size on the rheological properties is much greater than that of the particle shape. The small particle size is evidently affected by the shear rate, and the rheological parameters increase with time. The three rheological models can well describe the samples containing microfine cement (MC), fly ash (FA) and calcium carbonate whisker (CaCO3 whisker). The sample containing nano-silica (nano-SiO2) requires special analysis. The yield stress predicted by the Bingham model is the highest, whereas that predicted by the Herschel–Bulkley model is the lowest. The plastic viscosity predicted by the Bingham model is lower than that predicted by the modified Bingham model. The rheological index (n) of the Herschel–Bulkley model can effectively characterize the degree of shear thinning. The three rheological models demonstrate their characteristics and advantages, and an appropriate rheological model should be selected to evaluate the rheological parameters according to the requirements. The research aims to provide theoretical support for the analysis of rheological properties and the selection of rheological models.