Combined impact of silicate-amorphicity and MgO-reactivity on the performance of Mg-silicate cement

This work investigated the synergistic impact of silicate- and MgO-reactivity on the performance of Mg-silicate-based cement. Ceramic waste (CW) and glass waste (GW) as two silicate sources were used. Different decarbonation temperatures (800 and 1200 degrees C) were applied on magnesium carbonate to yield MgOs with different reactivities (MgO800 and MgO1200). Highest strength and shortest setting times associated with an enhancement in silicate dissolution rate and the formation of large magnesium silicate hydrate (MSH) were recorded in case of GW-MgO800-H2O system. The use of MgO1200 resulted in the retardation of MSH-formation rate in both of GW-MgO-H2O and CW-MgO-H2O systems. Comparing with GW-MgOs set, the CW-MgOs one showed the lowest performance at all curing ages. Due to high alumina content in CW, secondary hydrotalcite-like phases were detected in CW-MgOs alongside MSH-phase. (C) 2018 Elsevier Ltd. All rights reserved.