Abstract

The effect of CO2 curing on alkali-activated slag paste activated by a mixture of sodium hydroxide and sodium silicate solutions is reported in this paper. The paste samples after demolding were cured in three different curing environments as follows: (1) environmental chamber maintained at 85% relative humidity (RH) and 25 °C; (2) 3-bar CO2 pressure vessel; and (3) CO2 chamber maintained at 20% CO2 concentration, 70% RH and 25 °C. The hardened samples were then subjected to compressive strength measurement, X-ray diffraction analysis, and thermogravimetry. All curing conditions used in this study were beneficial for the strength development of the alkali-activated slag paste samples. Among the curing environments, the 20% CO2 chamber was the most effective on compressive strength development; this is attributed to the simultaneous supply of moisture and CO2 within the chamber. The results of X-ray diffraction and thermogravimetry show that the alkali-activated slag cured in the 20% CO2 chamber received a higher amount of calcium silicate hydrate (C-S-H), while calcite formed at an early age was consumed with time. C-S-H was formed by associating the calcite generated by CO2 curing with the silica gel dissolved from alkali-activated slag.

Department(s)

Civil, Architectural and Environmental Engineering

Publication Status

Open Access

Comments

Ministry of Trade, Industry and Energy, Grant 20188550000580

Keywords and Phrases

Alkali-activated slag; C-S-H; Calcite; Carbonation curing; CO curing 2; Vaterite

International Standard Serial Number (ISSN)

1996-1944

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 Nov 2019

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