Paper Number
GG2 

Session
Arrested Systems: Gels and Glasses

Title
State behavior and kinetics of alkali-activated aluminosilicate gels

Presentation Date and Time
October 11, 2021 (Monday) 10:15

Track / Room
Track 6 / Ballroom 1

Authors (Click on name to view author profile)

1. Mills, Jennifer N. (University of Delaware, Chemical and Biomolecular Engineering)
2. Wagner, Norman J. (University of Delaware, Chemical & Biomolecular Engineering)

Author and Affiliation Lines (in printed abstract book)
Jennifer N. Mills¹ and Norman J. Wagner^2
1Chemical and Biomolecular Engineering, University of Delaware, NEWARK, DE 19716; ²Chemical & Biomolecular Engineering, University of Delaware, Newark, DE 19716

Speaker / Presenter 
Mills, Jennifer N.

Keywords
experimental methods; applied rheology; gels; rheology methods

Text of Abstract
Cement production and use is one of the leading contributors to anthropogenic CO₂ emissions. Alkali-activated binders (AABs) present opportunities for significant reduction in CO₂ emissions, as well as in-situ resource utilization for lunar and Martian construction in support of human space exploration [1]. The chemical composition of these binders impacts macroscopic properties such as workability and strength, but further work is required to connect to the ‘geopolymer’ formation reaction and microstructure development. The rheological development with time and concentration is crucial for applications including traditional construction processes (pumping, pouring, setting) as well as additive manufacturing. A mechanistic and quantitative understanding of the chemical kinetics and dynamics of microstructure formation and associated rheology development in model AABs will facilitate the universal engineering of construction materials from a variety of aluminosilicate materials.
The structure-property relationships of these gels have been characterized based on the equilibrium storage modulus, which scales as a function of chemical composition consistent across multiple formulations. Complementary scattering and NMR measurements give further insight to microstructural differences in these states [2]. Additionally, the evolution of the storage modulus over time is fit to kinetic models which give insight to the reaction mechanism and quantify the kinetics with respect to the chemical composition. These experimental findings are summarized via a new pseudo-ternary state diagram, which provides a composition roadmap for rheological properties of aluminosilicate gels and AABs in the literature [3].
1. M. Katzarova, J.N. Mills, N.J. Wagner. Adv. Sp. Res. 2021. In Review.
2. J.N. Mills, N.J. Wagner, P. Mondal, J. Am. Ceram. Soc. 104 (2021) 572–583. https://doi.org/10.1111/jace.17459.
3. J.N. Mills, P. Mondal, N.J. Wagner. Cem. Conc. Res. 2021. Submitted.