Predicting CaO-(MgO)-Al2O3-SiO2 glass reactivity in alkaline environments from force field molecular dynamics simulations

TL;DR

This study uses force field molecular dynamics simulations to generate structural models of CMAS and CAS glasses, developing descriptors that better predict their reactivity in alkaline environments than traditional parameters.

Contribution

The paper introduces two novel structural descriptors derived from MD simulations that improve prediction of glass reactivity compared to existing methods.

Findings

MD simulations accurately capture key glass structures.

AMODE and ASDC descriptors outperform degree of depolymerization.

Descriptors effectively predict reactivity across diverse compositions.

Abstract

In this investigation, force field-based molecular dynamics (MD) simulations have been employed to generate detailed structural representations for a range of amorphous quaternary CaO-MgO-Al2O3-SiO2 (CMAS) and ternary CaO-Al2O3-SiO2 (CAS) glasses. Comparison of the simulation results with select experimental X-ray and neutron total scattering and literature data reveals that the MD-generated structures have captured the key structural features of these CMAS and CAS glasses. Based on the MD-generated structural representations, we have developed two structural descriptors, specifically (i) average metal oxide dissociation energy (AMODE) and (ii) average self-diffusion coefficient (ASDC) of all the atoms at melting. Both structural descriptors are seen to more accurately predict the relative glass reactivity than the commonly used degree of depolymerization parameter, especially for the eight synthetic CAS glasses that span a wide compositional range. Hence these descriptors hold great promise for predicting CMAS and CAS glass reactivity in alkaline environments from compositional information.