A molecular dynamics study of N-A-S-H gel with various Si/Al ratios

Y. Chen, Jorge S. Dolado, Suhong Yin, Qijun Yu, A. Kostiuchenko, Z. Li, G. Ye

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

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Abstract

The understanding of sodium aluminosilicate hydrate (N-A-S-H) gel is still limited due to its complex and amorphous structure. Recently, molecular dynamics simulation has provided a unique opportunity to better understand the structure of N-A-S-H gel from nanoscale. In this work, the N-A-S-H gel structure was obtained by simulating the polymerization of Si and Al monomers by molecular dynamics. The simulated polymerization process is in good agreement with the experimental results especially in terms of the reaction rate of Si and Al species. The atomic structural features of the N-A-S-H gel were analyzed in terms of bond length and bond angle information, simulated X-ray diffraction (XRD) and Qn distribution. A significant finding is the existence of pentacoordinate Al in all simulated N-A-S-H structures, indicating that pentacoordinate Al in geopolymer does not only come from raw material. Besides, the results show that a smaller Si/Al ratio led to a more crosslinked and compacted structure of N-A-S-H gel.
Original languageEnglish
Title of host publication4th International Rilem Conference on Microstructure Related Durability of Cementitious Composites
Subtitle of host publicationMicrodurability 2020
EditorsGuang Ye, Hua Dong, Jiaping Liu, Erik Schlangen, Changwen Miao
PublisherDelft University of Technology
Pages893-900
Number of pages8
ISBN (Electronic)978-94-6366-422-6
Publication statusPublished - 2021
Event4th International Rilem Conference on Microstructure Related Durability of Cementitious Composites - Online, Delft, Netherlands
Duration: 29 Apr 202127 May 2021
Conference number: 4
https://www.microdurability2020.com/99721

Conference

Conference4th International Rilem Conference on Microstructure Related Durability of Cementitious Composites
Abbreviated titleMicrodurability
CountryNetherlands
CityDelft
Period29/04/2127/05/21
Internet address

Keywords

  • molecular dynamics
  • N-A-S-H gel
  • atomic structures
  • Si/Al ratio

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