Estudo da reologia e da microestrutura de pastas de cimento Portland com adição de nanosílica estabilizada

Abstract

This work concernsthe study of rheology and microstructure of Portland cement pastes with stabilized nanosilica. The goal was toinvestigate the influence of stabilizednanosilica on microstructure of hard Portland cement pastes, as well as interferencesinfresh cement paste. For the rheology study, rheological parameters were evaluated by rheometry. In turn, the solid state nuclear magnetic resonance (29Si NMR CP MAS), scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques were used to evaluate the microstructure of hard paste. The study revealed that the addition of stabilized nanosilica contributes to the reduction of rheological parameters and consequent increase inflowability. Regarding the microstructure, the effects were more significant when stabilized nanosilica was used togheterwith silica fume. In this case, a synergistic effect was observed between thepozzolans, resulting in greater organization of the microstructure, as well as in longer calcium silicatehydrated chains