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Solution‐Controlled Dissolution of Supplementary Cementitious Material Glasses at pH 13: The Effect of Solution Composition on Glass Dissolution Rates
Author(s) -
Snellings Ruben
Publication year - 2013
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.12480
Subject(s) - dissolution , cementitious , aqueous solution , silica fume , fly ash , ground granulated blast furnace slag , materials science , aluminosilicate , mineralogy , chemical engineering , portland cement , cement , solubility , chemistry , metallurgy , composite material , organic chemistry , engineering , catalysis
Supplementary cementitious materials ( SCM s) are widely used to partially replace portland clinker in blended cements. Reducing clinker contents further without compromising the development of early strength necessitates a better assessment and enhancement of the reactivity of the available SCM s. To this purpose, the reactivity of synthesized calcium aluminosilicate glasses covering a compositional range from blast‐furnace slags (BFS) over fly ashes to silica fume was analyzed by dissolution experiments. Initial glass dissolution rates were measured at 20°C and pH 13, and with varying initial concentrations of aqueous Al , Ca , and Si . At pH 13, glass dissolution rates were observed to scale linearly with the glass Ca /( Al + Si ) molar ratio. Ca ‐rich blast‐furnace type glass dissolution was shown to be up to one order of magnitude faster than tectosilicate fly ash and silica fume type glass dissolution, supporting different pathways to dissolution. In solutions that are strongly undersaturated with respect to hydrous glass and hydration products, glass dissolution rates are independent of changes in solution undersaturation and aqueous Si activity. In contrast, dissolution rates decrease with aqueous Ca concentration for all glasses and with aqueous Al concentration for tectosilicate‐type glasses. The insights gained are instrumental in finding ways to enhance SCM reactivity.