Topological Controls on the Dissolution Kinetics of Glassy Aluminosilicates
Tandre Oey, Isabella Pignatelli, Yingtian Yu, Narayanan Neithalath, Jeffrey W. Bullard, Mathieu Bauchy, Gaurav Sant
Fly ash which encompasses a mixture of glassy and crystalline aluminosilicates is an abundant supplementary cementitious material (SCM), valuable for replacing ordinary portland cement (OPC) as the binder fraction in concrete. As a result of the demand for higher OPC replacement levels with fly ashes, it is essential to better understand and quantify fly ash reactivity. Through the combination of molecular dynamics (MD) simulations and vertical scanning interferometry (VSI), this study establishes the reactivity (i.e., the aqueous dissolution rate) of the glassy fractions in a suite of fly ashes (i.e., two ranges in the class of fly ash C1to C3 and F1 to F4) with water, which is controlled by the number of constraints placed on atoms within the disordered aluminosilicate network. More precisely, an exponential dependence of dissolution rates on the atomic network topology is observed. Such topological controls on fly ash reactivity are highlighted for a range of U.S. commercial fly ashes spanning the Ca- enriched and Si-enriched compositions. The structure-property relationships reported herein establish an improved framework to control and estimate fly ash-cement interactions in concrete.
, Pignatelli, I.
, Yu, Y.
, Neithalath, N.
, Bullard, J.
, Bauchy, M.
and Sant, G.
Topological Controls on the Dissolution Kinetics of Glassy Aluminosilicates, Journal of the American Ceramic Society, [online], https://doi.org/10.1111/jace.15122
(Accessed March 4, 2024)