E. Irassar-Viviana Rahhal, C. Pedrajas, R. Talero
Universidad Nacional del Centro de la Provincia de Bs. As., AR
calcined clays, cement, pozzolanic, rheology
In this paper, the rheological behavior of pastes of Portland cement and different calcined clays additions were analyzed. For this purpose, two Portland cements with different mineralogical composition (low C3A and high C3S content and low C3S and high C3A content) combined with different replacement percentages of three minerals additions of aluminic nature (quartz as control, and two metakaolins) are used. Mineral admixtures have different crystallinity and morphology: the quartz is fully crystalline; metakaolins are vitreous with a small fraction crystalline. The vitreous phase gives to the calcined clays, pozzolanic properties. All determinations were performed on Haake Roto Visco at 25° C, just on the latency period of hydration. The results show that Portland cement with low C3A content and high C3S content present great shear resistance and the replacement by calcined clays addition affect the rheological behavior of paste depending on the pozzolanic nature and the reactivity.