Effect of fly ash microsphere on the rheology and microstructure of alkali-activated fly ash/slag pastes

By Tao Yang, Huajun Zhu, Zuhua Zhang, Gao Xuan, Changsen Zhang, Qisheng Wu. Cement and Concrete Research, 2018

356 citations recorded by the source corpus.

Abstract The highly viscous property of alkali silicate-activated cements is one of the critical challenges that hinder their wide application. The present study focuses on ameliorating the rheological performance of sodium silicate-activated fly ash/slag pastes by using fly ash microsphere (FAM), which are highly spherical particles collected from fly ash with electrostatic adsorption classification technology. The FAM particles work as ‘ball-bearings’ in the pastes to reduce the internal friction between fly ash and slag grains, and meanwhile mitigate the agglomeration of flocs and fragmentation to release the locked water. The interrelationship between the FAM particle geometry and plastic viscosity of the paste is well described by the Krieger-Dougherty equation, which supports the proposed mechanisms of ‘ball-bearings’ effects. FAM can work as an inorganic dispersing agent to improve the workability of alkali-activated cement products for a variety of application aspects.

Subfields: Building and Construction, Civil and Structural Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/df052452ae83924f7c394c65896ee3c8f664374e