Molecular Dynamics Study of the Interaction of C-S-H and Chloride Ions

Abstract:

Molecular Dynamics was employed to investigate the interaction of calcium silicate hydrate (C-S-H), the primary hydration product of cement based materials, and chloride, causing severe durable problems of concrete. The 11Å tobermorite structure was chosen to describe the C-S-H structure and the CLAYFF force field was used. It is observed in the simulation that there are no bound chlorides at 303K, while a fraction of chlorides appear in the adsorption district of tobermorite/solution interface at 323K indicating the temperature increase can improve chloride sorption capacity of C-S-H. The formation of Ca-Cl cluster is found on the surface of tobermorite, which is assumed to promote the chloride sorption. The experimental results of sorption isotherms of C-S-H in CaCl₂ and NaCl aqueous solutions with the same chloride concentration have proved this point. Other researchers have made the same conclusion by means of molecular dynamics modeling, NMR tests or zeta potential experiments.

• Periodical: Key Engineering Materials (Volume 711)
• Pages: 1061-1068
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.711.1061
• Online since: September 2016
• Authors: Yang Zhou*, Guo Dong Xu
• Keywords: Chloride, C-S-H, Molecular Dynamics, Sorption

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