Chloride Binding Mechanism in Seawater-Mixed UHPC

Author

Wei Zhang
Dawei Ding
Mengmeng Li
Tiao Wang
Hongyan Ma, Missouri University of Science and TechnologyFollow
Binmeng Chen
Hongxing Hu
Jizhou Chen
Xiaomin Liu
Dongshuai Hou

Abstract

The rapid development of marine concrete structures and the sharp shortage of freshwater resources contribute to the wide investigation of seawater-mixed ultra-high-performance concrete (swuhpc). However, few studies have investigated the chloride ions (cl-) binding mechanism of swuhpc. Herein, the chloride binding experiments and molecular dynamics (md) simulation were carried out to reveal the physically and chemically bound cl- mechanisms of swuhpc. The results of the experiments clearly demonstrate that the addition of silica fume (sf) led to a significant decrease in the capacity of cl- binding. Conversely, the incorporation of metakaolin (mk) resulted in a marked increase in the content of chemically bound cl-. Furthermore, it is revealed through md simulations that the amount of physically bound cl- heavily depends on the ca/si ratio of c-s-h. A higher ca/si ratio results in a stronger electrostatic effect of the c-s-h surface on cl-, which increases the physical binding of cl- via ca-cl bonds. In addition, it is found that al[6] and ca in the interlayer region of c-a-s-h formed the main structure layer (ca4al2(oh)122+) of friedel's salt, and then chemically adsorbed cl- in the pore solution. These findings provide novel nanoscale insights regarding the physically and chemically bound cl- mechanisms of swuhpc.

Recommended Citation

W. Zhang and D. Ding and M. Li and T. Wang and H. Ma and B. Chen and H. Hu and J. Chen and X. Liu and D. Hou, "Chloride Binding Mechanism in Seawater-Mixed UHPC," Construction and Building Materials, vol. 427, article no. 136191, Elsevier, May 2024.

The definitive version is available at https://doi.org/10.1016/j.conbuildmat.2024.136191

Department(s)

Civil, Architectural and Environmental Engineering

Comments

National Natural Science Foundation of China, Grant 52178221

Keywords and Phrases

Ca/Si ratio; Chloride binding mechanism; Friedel's salt; Molecular dynamics simulation; Seawater-mixed UHPC

International Standard Serial Number (ISSN)

0950-0618

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2024 Elsevier, All rights reserved.

Publication Date

10 May 2024