Microstructural densification and CO2 uptake promoted by the carbonation curing of belite-rich Portland cement

Abstract

The present study investigates the effects of the belite content and carbonation curing on the physicochemical properties of cement mortar. The results provide new insight, demonstrating that a higher belite content in cement increases CO2 uptake during the carbonation curing process and thus promotes microstructural densification. Carbonation-cured cement with a high alite content showed increased pore connectivity, while the cement with a high belite content experienced reduced pore connectivity and more instances of pore closure, resulting in a complex microstructure. The belite phase was mostly consumed by the carbonation reaction during the curing process, resulting in the production of calcite. As a result, the mechanical strength of the carbonation cured belite-rich Portland cement mortar was significantly improved in comparison with that after normal curing for an identical period. In particular, the reaction of the belite phase influenced by hydration/carbonation interaction at an early age is discussed along with the experimental results. (C) 2016 Elsevier Ltd. All rights reserved.