Influence of the alkaline solution and temperature on the rheology and reactivity of alkali-activated fly ash pastes. (January 2019)

• Record Type: Journal Article
• Authors: Palacios, M.; Alonso, M.M.; Varga, C.; Puertas, F.
• Is Part Of: Cement & concrete composites. Volume 95(2019)
• Page Start: 277
• Page End: 284
• Publication Date: 2019-01
• Subjects: Alkali-activated fly ash -- Rheology -- Activation energy -- Temperature -- Alkaline activator; Composite-reinforced concrete -- Periodicals; Concrete -- Periodicals; Composite materials -- Periodicals; Composites de ciment -- Périodiques; Béton -- Périodiques; Composites -- Périodiques; Béton léger -- Périodiques; Cement composites; Composite materials; Composite-reinforced concrete; Concrete; Lightweight concrete; Periodicals; Electronic journals; 620.135
• DOI: 10.1016/j.cemconcomp.2018.08.010
• Languages: English
• ISSNs: 0958-9465

Abstract

Abstract: The aim of the present research is to ascertain the effect of the nature and concentration of the alkaline activator and temperature on the rheological behaviour of alkali-activated fly ash (AAFA) pastes. Furthermore, the reaction process of fly ash has been investigated from rheological measurements. Results have shown that the increase of the activator concentration and the temperature leads to an increase of yield stress and apparent viscosity, mainly at temperatures above 65 °C when dissolution of fly ash and precipitation of hydration products is raised. In general, similar activation energies were determined for alkali-activated fly ash pastes, regardless of the concentration and silica modulus of the activator, concluding that the underlying reaction mechanism is the same independently on the nature of the activating solution.