MgO recently has been regarded as the alternative material for replacement of cement. The aim of this study is to investigate the effects of accelerated carbonation on the strength development of MgO-based binder which is binary mixtures of magnesium oxide (MgO) with portland cement (PC) or ground granulated blast furnace slag (GGBS) or fly ash (FA). The compressive strengths of all binders were higher in the 20%
CO2 condition and for longer curing time. The strength were generally higher as the following order: MgO/PC > MgO/GGBS > MgO/FA system. The binder composed of 20% MgO and 80% PC showed highest compressive strength (38.0MPa) which was higher than PC. The correlation analysis of the porosity and compressive strength showed that compressive strength was higher when porosity was lower. The hydration and carbonation products of MgO including brucite (
Ca(OH)2), magnesite (
MgCO3) and nesquehonite (
MgCO3⋅3H2O) presumably filled the pores and contributed to strength development. Thermogravimetric analyses elucidated that 0.34 kg of
CO2 could be stored the 50% MgO/50% PC binder which performed the maximum
CO2 uptake at 20%
CO2 condition.
Keywords: MgO-based binder;Accelerated carbonation;Compressive strength;Industrial by-products;Portland cement;