Influência de micro e nano reforço celulósico na hidratação e resistência mecânica de pastas de cimentação leves e de densidade normal

Abstract

The objective of this research was to evaluate the influence of microcrystalline cellulose (MCC) and nanocellulose (MFC) on the hydration of cured cement pastes at temperatures of 23 °C and 60 °C and water/cement ratios of 0.45 and 0.90. Using the isothermal calorimetry technique, the influence of different mass fractions (0.25-1.0%) of cellulosic fibers on nano, micro and millimeter scales on hydration was studied. The reduction in fiber size decreased the delay caused by the presence of fibers, comparing pastes with the same reinforcement mass fraction. By thermal analysis data, the evolution of the formation of hydration products over time for pastes containing different MCC and MFC contents was evaluated. The results show that the MCC and MFC-added pastes presented higher total combined water content than the reference paste, especially after 24 hours of hydration. However, this is strongly related to the amount of water adsorbed by the different celluloses and their concentrations in the mixture. Light and normal density pastes were characterized for stability, hydration and evolution of mechanical resistance, aiming a potential application in the oil wells cementing.