Rheological characterization of fly ash-based suspensions

• The yield stress is mainly influenced by temperature.
• The type of dispersant used have only a moderate influence on the rheology.
• Solid content is the most influential parameter on apparent viscosity.
• The apparent viscosity was found to decrease with temperature.
• Design of experiment is a valid support in the study of the geopolymer rheology.

The importance of flow properties in most handling techniques requires specific characterizations of geopolymer rheology in the fresh state. In this work, a Design of Experiment (DOE) approach was used to evaluate the influence of solid load, temperature and dispersant on apparent viscosity and yield stress of fly ash-based geopolymers. The solid load was found to be the most influential variable on viscosity. An increase in solid load led to an increase in apparent viscosity but also of yield stress. Apparent viscosity was found to have an Arrhenius type relationship with temperature. The influence of dispersant on yield stress and viscosity appeared to be minor.

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