Abstract

Blast-furnace slag, which contains high levels of CaO (and MgO), holds potential as a feedstock for CO2 capture and storage. This study investigates the phase transitions occurring during the wet carbonation of ground granulated blast-furnace slag (GGBFS), characterizes the physical and chemical properties of carbonated GGBFS (CS), evaluates its pozzolanic reactivity, and examines the microstructure and performance of cement pastes blended with GGBFS or CS. The findings reveal that aragonite and calcite, the primary carbonation products, precipitate on the surface of GGBFS, hindering its dissolution and thereby reducing both the pozzolanic reactivity and the early strength of cement pastes. Nevertheless, the 28-day strength of CS blended pastes is comparable to that of GGBFS blends, due to the improved pore structure and the interfacial transition zone between CS and hydration products, which is attributed to the stabilization of ettringite and the formation of monocarboaluminate and hemicarboaluminate phases induced by the calcium carbonate introduced through CS. This characteristic implies extra benefits of using CS against GGBFS apart from CO2 sequestration, that is, the potential of CS to be used in projects requiring low early-age heat.

Department(s)

Civil, Architectural and Environmental Engineering

Publication Status

Open Access

Keywords and Phrases

Carboaluminate; Carbonation; GGBFS; Performance of cement pastes; Pozzolanic reactivity

International Standard Serial Number (ISSN)

1873-4197; 0264-1275

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2026 Elsevier, All rights reserved.

Creative Commons Licensing

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Publication Date

01 Jan 2026

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