$CO_2$ uptake and physicochemical properties of carbonation-cured ternary blend Portland cement-metakaolin-limestone pastes

Abstract

The feasibility of carbonation curing of ternary blend Portland cement-metakaolin-limestone was investigated. The ternary blend Portland-metakaolin-limestone pastes present a high replacement of Portland cement exhibiting good mechanical and durability performance. Carbonation curing was coupled with this blend to achieve ecofriendly binder. Portland cement was substituted with combinations of metakaolin and limestone at 15%, 30%, and 45% by mass, and exposed to four different combinations of ambient curing and carbonation curing. Carbonation durations were varied as 6 hours, 13 days and 27 days. The mechanical strength, $CO_2$ uptake and mineralogical variations were investigated by means of compressive strength test, thermogravimetric analysis, and X-ray diffractometry. Volume of permeable voids and sorptivity were presented to provide a fundamental idea of this blends. Results showed that the ternary blend Portland cement-metakaolin-limestone systems enhanced the $CO_2$ uptake by increasing the porosity of the system. The blends of up to 15 wt.% replacement with metakaolin and limestone showed comparable mechanical strength to OPC, proving that this system can be a viable option toward the development of ecofriendly binders.