Effect of calcium on the alkaline activation of aluminosilicate glass

The present study explored the alkali reactivity of aluminosilicate glass with a variable (from 0 to 40 weight per cent) CaO content. The findings showed that the presence of CaO in the raw mix conditions the formation of vitreous material and post-activation mechanical strength development. Vitreous matrices with a CaO content of up to 20% are uniform and highly reactive, generating mechanically strong systems after alkaline activation. CaO concentrations of 40% or over limit the formation of a vitreous matrix, favouring the synthesis of a very non-uniform system, primarily comprising different types of calcium silicates that are scantly reactive in the presence of alkaline activators. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.