Hydration kinetics and products of MgO-activated blast furnace slag

Abstract

Hydration kinetics and products of MgO-activated slag are investigated by employing multiple analytical characterization techniques and thermodynamic modelling. The main hydration products of this cement are a calcium-aluminosilicate hydrate type gel, ettringite, monosulfate, hydrotalcite, brucite, and a third aluminate hydrate, while the extent of reaction and formation of reaction products significantly varied by MgO dosages. Higher dosage of MgO increased the degree of reaction of slag, and led to a higher population of Al in the octahedral region, which can be attributed to greater competition for Al required for the formation of hydrotalcite. The experimental and simulated volume of the solid binder increased as the MgO dosage increased, showing a good correlation with the strength increase of the samples with higher MgO dosage. (C) 2020 Elsevier Ltd. All rights reserved.