Resumo

RAHHAL, Viviana F.; PEDRAJAS, César; IRASSAR, Fabián  e  TALERO, Rafael. Efecto de puzolanas naturales sobre la reolología de pastas de cemento portland. Concr. cem. investig. desarro [online]. 2014, vol.5, n.2, pp.02-11. ISSN 2007-3011.

In this paper the influence of three spanish natural pozzolans of different chemical character were analyzed on two portland cements with very different mineralogical composition (with opposite C₃A and C₃S content) and with different replacement percentages. All determinations were made at 25°C and just at the dormant periods of their hydration. The results showed that the cement with low C₃A and high C₃S, had higher shear stress than the cement with high C₃A and low C₃S; but its recovery was lower. In the pastes with natural pozzolans, the shear stress increased when the proportion of reactive alumina was higher for a particular replacement percentage. At the time the rotor stopped, the shear stress increase was more significant in the case of cement mixtures with high C₃A. Finally as the shear stress increased, with higher percentage replacement for the pozzolans A and C; while for the pozzolan O it decreased, possibly due to its low adsorption.

Palavras-chave : reology; cement pastes; natural pozzolans.