Abstract

This study investigated characteristics of alkali-activated slags incorporating magnesium oxide (MgO) subjected to CO2 curing. The samples were prepared by adding 2%, 5%, and 10% MgO to the total binder mass. The mixture was activated with potassium hydroxide (KOH) and cured in a CO2 incubator for 3 days. The compressive strength of the MgO-incorporated CO2-cured alkali-activated slag was higher than that of the conventional alkali-activated slag at all ages up to 28 days. No reduction in the strength was observed over time. The enhanced strength was independent of MgO content. Combined X-ray diffraction with thermogravimetric analysis showed MgO accelerated the alkali activation by dissolving more Ca and Al ions from the slag. CO2 curing supplied carbonate ions and produced calcium carbonate and hydrotalcite. The former aided in achieving a higher level of early age strength and gel pore refinement. Larger amount of the carbonates was formed under high MgO contents, which further enhanced the strength.

Department(s)

Civil, Architectural and Environmental Engineering

Publication Status

Full Text Access

Comments

National Research Foundation of Korea, Grant NRF-2020R1I1A1A01072504

Keywords and Phrases

Calcite; Carbonate ion; CO curing 2; Hydrotalcite; MgO

International Standard Serial Number (ISSN)

0950-0618

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2025 Elsevier, All rights reserved.

Publication Date

24 May 2024

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