Abstract
The injection of carbon dioxide (CO2) into cementitious systems has emerged as a promising approach to enhancing sustainability in concrete production. This study explores the impact of CO2 injection on the rheological behavior, structural build-up, and particle size evolution of cement paste by systematically varying the water-to-cement ratio (w/c) (0.35, 0.4, and 0.5) and CO2 concentration (0.06, 0.28, and 0.84 mol). Rheological analysis revealed a significant increase in initial yield stress with CO2 injection. Using the Modified Bingham model, yield stress increased by 72 % and 150 % for 0.28- and 0.84-mol CO2, respectively, while the Herschel-Bulkley model indicated corresponding increases of 31 % and 76 %. Structural build-up rates also exhibited substantial enhancement, reaching 23 Pa/min for 0.28-mol CO2 and 106 Pa/min for 0.84-mol CO2, whereas negligible changes were observed in CO2-free samples. Note that lower w/c (e.g., 0.35) demonstrated superior rheological improvements, with a 310 % increase in yield stress, highlighting the role of free water in facilitating carbonation reactions. Shear-thinning behavior intensified with CO2 injection, particularly at low shear rates (10−2 to 10−1 s−1), while viscosity changes diminished at higher shear rates (101 to 103 s−1) due to particle network disruption. Slump flow tests further confirmed alterations in flow characteristics following CO2 injection. Analytical techniques, including multiple light scattering, X-ray diffraction (XRD), and thermogravimetric analysis (TG), indicated the formation of CaCO3 in the form of aragonite and calcite, contributing to particle agglomeration and enhanced stability.
Recommended Citation
S. Han et al., "CO2-induced Changes In Rheology, Structural Evolution, And Particle Characteristics Of Cement Paste," Cement and Concrete Composites, vol. 163, article no. 106180, Elsevier, Oct 2025.
The definitive version is available at https://doi.org/10.1016/j.cemconcomp.2025.106180
Department(s)
Civil, Architectural and Environmental Engineering
Publication Status
Full Text Access
Keywords and Phrases
Carbon dioxide; Particle size evolution; Rheology modification; Structural build-up
International Standard Serial Number (ISSN)
0958-9465
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2025 Elsevier, All rights reserved.
Publication Date
01 Oct 2025
Included in
Architectural Engineering Commons, Civil Engineering Commons, Engineering Education Commons, Materials Science and Engineering Commons, Structural Engineering Commons, Transportation Engineering Commons
Comments
National Research Foundation of Korea, Grant RS-2023-NR077131