Abstract

This study investigated the efficiency of CO2 curing in blast-furnace slag pastes activated with three concentrations of KOH solution (3, 4, and 5 M). The CO2 curing was applied into the alkali-activated slag paste for 3 days. The CO2-cured pastes were subjected to subsequent curing in a water bath or exposed to seawater. The mechanical properties and characteristics of the reaction products were compared. Full strength can be obtained within 3 days of the early CO2 curing. The strength remained almost constant regardless of the activator concentration. The CO2-cured samples produced more CaCO3 after exposure to the seawater. The carbonates filled the micropores of the samples, and no strength reduction was observed. The hydrates Ca(OH)2 and C–S–H(I) are carbonated, forming calcite and amorphous CaCO3 during the subsequent curing and exposure to seawater as well as the CO2 curing. A less dense matrix with a lower activator concentration facilitated the diffusion of CO2 and promoted early carbonation in the paste. The polymerization of C–S–H(I) was relatively slow with low activity, and within the period of CO2 curing, more carbonates were produced in the sample prepared at a low activator concentration.

Department(s)

Civil, Architectural and Environmental Engineering

Publication Status

Open Access

Comments

Ministry of Education, Grant NRF-2020R1I1A1A01072504

Keywords and Phrases

Alkali-activated slag; Amorphous CaCO 3; Calcite; CCUS; CO curing 2

International Standard Serial Number (ISSN)

2234-1315; 1976-0485

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2025 The Authors, All rights reserved.

Creative Commons Licensing

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

Publication Date

01 Dec 2023

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