Microstructure development and binder formation kinetics in alkali-activated aluminosilicates measured via stopped-flow USAXS

The early-age structure of amorphous alkali aluminosilicate gels, the binding phase in low-CO2 alternative cements, will be characterized for the first time using a stopped-flow apparatus paired with SAXS and USAXS to support a kinetic model describing the mechanism of gel formation. The analysis of a wide range of gel chemistries will provide critical insight into changes in structure and kinetics due to gel chemical composition. The USAXS beamline at ESRF is uniquely poised to investigate this system due to the required q-range of 0.001 nm-1 to 1 nm-1 along with a time resolution of several milliseconds. Understanding the time-resolved structure is critical for chemical formulation strategies to control rheological properties of low-CO2 geopolymer cement binders. Measurements of the time-resolved geopolymer structure will also aid ongoing international collaboration between the CEA in France and the University of Delaware in the United States.