Abstract

In this study, experimental characterization and reactive molecular dynamics simulations were integrated to reveal the effects of NaCl on the early hydration of tricalcium silicate (C3S). The results demonstrate that NaCl significantly accelerates the early hydration of C3S by promoting Ca dissolution and silicate tetrahedra polymerization. Specifically, Clions coordinate with surface Ca, weakening the Ca–O bonds in C3S and reducing the energy barrier for Ca dissolution. Meanwhile, Na+ions compete with Ca2+for the O atoms, creating localized charge imbalance and attracting protons, which destabilize Si–O bonds and facilitate the polymerization of silicate tetrahedra. These effects are further amplified at elevated temperatures, which accelerate Ca dissolution and silicate chain formation. For the first time, an atomistic dual-pathway mechanism is proposed in this study, where Clfacilitates Ca dissolution while Na+drives silicate polymerization during early C3S hydration, advancing the molecular-level understanding of ionic effects in cement hydration.

Department(s)

Civil, Architectural and Environmental Engineering

Comments

National Key Research and Development Program of China, Grant 2022YFE0133800

Keywords and Phrases

hydration; NaCl; reactive molecular dynamics; temperature; tricalcium silicate

International Standard Serial Number (ISSN)

2168-0485

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2025 American Chemical Society, All rights reserved.

Publication Date

20 Oct 2025

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