Compressive strength, water and chloride transport properties of early CO2-cured Portland cement-fly ash-slag ternary mortars

Abstract

Early CO2 curing is a promising technology for improving the strength and long-term durability of mortar and concrete as well as CO2 sequestration. However, the effects of supplementary cementitious materials (SCMs) such as fly ash and slag on the chloride transport properties of cement-based materials subjected to early CO2 curing are not clear. In this study, compressive strength, water and chloride transport behaviors of Portland cement-fly ash-slag ternary mortars subjected to early CO2 curing and subsequent lime water curing were determined. The obtained results indicated that the addition of fly ash and slag lowered the compressive strength, water and chloride ions penetration resistance of cement mortars at the late age. Regarding the mechanical and transport properties, the replacement level of fly ash and slag in early CO2-cured cement mortars should not exceed 25% when it exposure to chloride ions. Slag had less influence on the mechanical and transport properties of early CO2-cured cement mortars than fly ash due to finer particle size of the former.