Insights into the stirring rate and limestone powder content on the rheological behavior of cement paste: Particle packing, ionic strength and hydration

This study delves into how varying levels of stirring rate and limestone powder content influence the rheological behavior of cement paste, focusing on both dynamic yield stress (DYS) and static yield stress (SYS). To uncover the underlying mechanisms, the study examines particle water film thickness (WFT), ionic strength within the interstitial solution, and hydration characteristics. The results indicate that increasing the stirring rate and the limestone powder content reduces the DYS and the initial static yield stress (ISYS) of the slurry due to the increase in the WFT and the decrease in the ionic strength. However, the enhanced stirring rate facilitates the hydration products to precipitate, thereby speeding up the hydration process and, as a result, increasing the growth rate of the SYS in the acceleration stage progressive. Increasing the limestone powder content reduces the growth rate of SYS due to its reduction in hydration rate. Overall, this study offers deeply insights into how stirring rate and limestone powder content affects the cement pastes’ rheological behavior.