  The reactivity of amorphous aluminosilicates in alkaline environments is
important to many applications, including blended Portland cements and
alkali-activated materials (AAMs). Here, two physics-based compositional
parameters are derived to describe the relative reactivity of CaO-Al2O3-SiO2
and CaO-MgO-Al2O3-SiO2 glasses in alkaline environments: (i) a modified average
metal oxide dissociation energy (AMODE) parameter developed from molecular
dynamics simulations; and (ii) a topology constraint parameter derived from
topological constraint theory. Both parameters are seen to generally outperform
existing compositional parameters from the literature for a wide range of
aluminosilicate glasses. Given that both the modified AMODE and topology
constraint parameters can be calculated directly from chemical compositions,
this study represents a major step forward in connecting aluminosilicate glass
compositions with their reactivity in alkaline environments. The limitations of
these compositional parameters, including their inability to capture the impact
of Ca versus Mg on glass reactivity, have also been discussed.
