Investigating the Seeding Effects of Nano-ettringite on the Hydration and 3D Microstructure of Calcium Sulfoaluminate Cement Paste
Abstract
Ettringite is the primary hydration product responsible for early strength development in calcium sulfoaluminate (CSA) cement systems. While fine ettringite particles are known to enhance hydration, their impact on mechanical performance remains inconsistent, and the mechanisms behind nano-ettringite seeding—particularly its influence on time-dependent rheology, phase assemblage, 3D microstructure, and strength development—are not fully understood. This study investigates the effects of nano-ettringite on the hydration behavior and properties of CSA cement pastes. Rheology, isothermal calorimetry, X-ray diffraction (XRD), X-ray micro-computed tomography (μCT), and compressive strength tests were employed to evaluate workability, hydration kinetics, phase development, pore structure, and strength development. Nano-ettringite accelerated the nucleation and growth of hydration products, modifying phase assemblage and enhancing hydration kinetics. At a 1 % dosage, nano-ettringite reduced the induction time and placement limit metrics by 17 % each, increased the rate of flowability loss by 98 %, and accelerated the hardening rate by 42 %. The intensity of ettringite peaks in XRD increased by over 120 % after 3 h with 5 % seeding. 3D microstructure analysis showed a 72 % and 50 % reduction in resolvable pore volume at 1 and 28 days, respectively, for the 1 % dosage, although pore connectivity increased by 52 % and 252 % at the same ages. Compressive strength improved modestly by 1 %, 7 %, and 4 % at 1, 7, and 28 days, respectively, for the 1 % dosage. Overall, nano-ettringite seeding was found to enhance hydration kinetics, rheological behavior, microstructural refinement, and early-age strength development in CSA cement pastes.
Recommended Citation
R. R. Halder et al., "Investigating the Seeding Effects of Nano-ettringite on the Hydration and 3D Microstructure of Calcium Sulfoaluminate Cement Paste," Journal of Building Engineering, vol. 113, article no. 114079, Elsevier, Nov 2025.
The definitive version is available at https://doi.org/10.1016/j.jobe.2025.114079
Department(s)
Chemical and Biochemical Engineering
Keywords and Phrases
3D microstructure; Hydration; Nano-ettringite; Sulfoaluminate cement; Time-dependent rheology
International Standard Serial Number (ISSN)
2352-7102
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2025 Elsevier, All rights reserved.
Publication Date
01 Nov 2025
Comments
Missouri University of Science and Technology, Grant 1932690