Topological controls on aluminosilicate glass dissolution: Complexities induced in hyperalkaline aqueous environments
- Laboratory for the Chemistry of Construction Materials (LC2) Department of Civil and Environmental Engineering University of California, Los Angeles Los Angeles CA USA, VTT Technical Research Centre of Finland Ltd. Espoo Finland
- Laboratory for the Chemistry of Construction Materials (LC2) Department of Civil and Environmental Engineering University of California, Los Angeles Los Angeles CA USA, Department of Materials Science and Engineering University of Texas at Arlington Arlington TX USA
- Laboratory for the Chemistry of Construction Materials (LC2) Department of Civil and Environmental Engineering University of California, Los Angeles Los Angeles CA USA, CO2Concrete LLC Santa Fe NM USA
- Laboratory for the Physics of Amorphous and Inorganic Solids (PARISlab) Department of Civil and Environmental Engineering University of California, Los Angeles Los Angeles CA USA
- Laboratory for the Chemistry of Construction Materials (LC2) Department of Civil and Environmental Engineering University of California, Los Angeles Los Angeles CA USA
- Zachry Department of Civil and Environmental Engineering Texas A&,M University College Station TX USA, Department of Materials Science and Engineering Texas A&,M University College Station TX USA
- Laboratory for the Chemistry of Construction Materials (LC2) Department of Civil and Environmental Engineering University of California, Los Angeles Los Angeles CA USA, Department of Materials Science and Engineering University of California, Los Angeles Los Angeles CA USA, California Nanosystems Institute (CNSI) University of California, Los Angeles Los Angeles CA USA, Institute for Carbon Management (ICM) University of California, Los Angeles Los Angeles CA USA
Fly ash, an aluminosilicate composite consisting of disordered (major) and crystalline (minor) compounds, is a low‐carbon alternative that can partially replace ordinary portland cement (OPC) in the binder fraction of concrete. Therefore, understanding the reactivity of fly ash in the hyperalkaline conditions prevalent in concrete is critical to predicting concrete's performance; including setting and strength gain. Herein, temporal measurements of the solution composition (using inductively coupled plasma‐optical emission spectrometry: ICP‐OES) are used to assess the aqueous dissolution rate of monophasic synthetic aluminosilicate glasses analogous to those present in technical fly ashes, under hyperalkaline conditions (10 ≤ pH ≤ 13) across a range of temperatures (25°C ≤ T≤45°C). The dissolution rate is shown to depend on the average number of topological constraints per atom within the glass network (n c , unitless), but this dependence weakens with increasing pH (>10). This is postulated to be on account of: (a) time‐dependent changes in the glass’ surface structure, that is, the number of topological constraints; and/or (b) a change in the dissolution mechanism (eg from network hydrolysis to transport control). The results indicate that the topological description of glass dissolution is most rigorously valid only at very short reaction times (ie at high undersaturations), especially under conditions of hyperalkalinity. These findings provide an improved basis to understand the underlying factors that affect the initial and ongoing reactivity of aluminosilicate glasses such as fly ash in changing chemical environments, for example, when such materials are utilized in cementitious composites.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1644126
- Journal Information:
- Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 11 Vol. 103; ISSN 0002-7820
- Publisher:
- Wiley-BlackwellCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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