Resumen de Portland cement pastes: analysis and study of their rheological behaviour and other concomitant physics-chemical parameters
Viviana Fátima Rahhal, Carlos Aramburo, César Pedrajas Nieto-Márquez, Antonio Blázquez Morales, Rafael Talero Morales
A careful selection of the parameters used to evaluate the rheological behaviour of plain fresh pastes of Portland cements is very important. The initial analysis explored the variations in rheometer response depending on angular velocity and phase duration. Ramp direction, number of angular velocities, the size of the inter-velocity steps and the importance of allowing the cement paste sample were also studied. These trials were conducted on two types of Portland cements with completely different mineralogical compositions. They were repeated every 20 minutes up to the first nadir on their heat of hydration release curves, determined in earlier conduction calorimetry studies.
The results showed that parameter selection in designing a scheme had a substantial effect on the response obtained. That response was also highly dependent upon the degree and type of hydroxy-induced alkalinity in the liquid phase of the pastes, in turn a result of the mineralogical and chemical composition of the PCs, in particular their N2O and K2O (%) contents, which therefore proved to play a prominent role in rheological behaviour.
