Synthesis, solubility and thermodynamic properties of N-A-S-H gels with various target Si/Al ratios

Journal article (2024)

Authors

Y. Chen Materials and Environment - CEG , South China University of Technology
Zhenming Li Harbin Institute of Technology
Bin Ma Paul Scherrer Institut
Barbara Lothenbach Swiss Federal Laboratories for Materials Science and Technology (Empa)
Suhong Yin South China University of Technology
Qijun Yu South China University of Technology
G. Ye Materials and Environment - CEG
Research Group
Materials and Environment (CEG) (TU Delft)
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Published Date

2024

Language

English

Faculty

Civil Engineering & Geosciences

Department

Materials- Mechanics- Management & Design

Research Group

Materials and Environment

Abstract

The synthesis of N-A-S-H gel with high Si/Al ratios (>2) has been rarely reported in the literature, leaving the establishment of a reliable synthesis route as an open challenge. This paper aims to synthesize N-A-S-H gels with Si/Al ratios ranging from 1 to 3 and establish their thermodynamic database. The effects of reaction temperature, reaction time, initial Si/Al, concentration of reactants and pH of the matrix on the Si/Al ratios of the synthesized N-A-S-H gel were investigated. Results showed that N-A-S-H gels with target Si/Al ratios can be synthesized by controlling the concentration of reactants, pH and initial Si/Al ratios. The solubility products of the obtained N-A-S-H gels were determined via dissolution tests at different temperatures, to determine thermodynamic data. The development of this experimentally derived thermodynamic database of N-A-S-H gels constitutes a crucial step in the advancement of thermodynamic modeling of geopolymer, providing valuable insight into geopolymer reactions and phase assemblages.