Influence of micro-silica and superplasticizers on the hydration and rheological behavior of calcium aluminate cement

Abstract

The study investigates the early hydration and rheological properties of calcium aluminate cement (CAC) modified with micro-silica (MS) and different superplasticizers. The influence of MS content (5%, 10%, and 15%) and superplasticizers (FS and NT) on hydration kinetics and dynamic viscosity were analyzed. Isothermal calorimetry results indicate that MS significantly accelerates hydration, reducing the time to peak heat release. However, increasing MS content from 5% to 15% leads to a decrease in cumulative heat release. The effect of superplasticizers varies depending on the MS concentration: FS enhances early hydration but loses effectiveness over time, while NT maintains workability for up to 60 minutes. Rheological tests reveal that higher MS content increases viscosity, likely due to reduced free water. The combined use of FS and NT results in intermediate viscosity and workability. These findings provide insights into optimizing CAC mixtures for improved performance in construction applications.