New insights on geopolymerisatton using molybdate, Raman, and infrared spectroscopy

authored by: C. H. Rüscher, E. Mielcarek, J. Wongpa, F. Jirasit, W. Lutz
Abstract: Geopolymerisation of an optimally alkali activated metakaolin cement was investigated in dependence on time by strength measurements, by infrared and Raman spectroscopy, and by the molybdate tracer method. The increase in flexural strength at the beginning of aging is explained by the development of two main structural units on different time scales: a fast formation of polymeric silicate chain type (polysiloxo) units and a slow formation of a three dimensional network crosslinking the chains and including sialate bondings. However during further aging a significant weakening occured due to the fragmentation and incorporation of the chain units into the aluminosilicate body. Variations in the waterglass to metakaolin ratio decreasing the nominative K/Al and Si/Al ratio produced about the same binder phase but led to a significant portion of unreacted metakaolin. Further silicate and aluminosilicate cements were synthesized based on rice husk-bark ash, slag, and combinations with slag and metakaolin. It is concluded that the formation and crosslinking of long silicate chains becomes crucial for gaining high mechanical strength and that the protection of the silicate chains becomes crucial for holding long time high strength. This protection is given in the presence of unresolved metakaolin and becomes more pronounced with the addition of significant amounts of CaO together with highly reactive SiO₂ source material (Slag).
Organisation(s): Institute of Mineralogy
Center for Solid State Chemistry and New Materials (ZFM)
External Organisation(s): King Mongkut's University of Technology Thonburi
Brandenburg University of Technology
Type: Conference contribution
Pages: 17-34
No. of pages: 18
Publication date: 27.09.2010
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Ceramics and Composites, Materials Chemistry
Electronic version(s): https://doi.org/10.1002/9780470944103.ch3 (Access: Closed)

BibTeX

@inproceedings{57bc9e0417874662a57355129cb4d120,
title = "New insights on geopolymerisatton using molybdate, Raman, and infrared spectroscopy",
abstract = "Geopolymerisation of an optimally alkali activated metakaolin cement was investigated in dependence on time by strength measurements, by infrared and Raman spectroscopy, and by the molybdate tracer method. The increase in flexural strength at the beginning of aging is explained by the development of two main structural units on different time scales: a fast formation of polymeric silicate chain type (polysiloxo) units and a slow formation of a three dimensional network crosslinking the chains and including sialate bondings. However during further aging a significant weakening occured due to the fragmentation and incorporation of the chain units into the aluminosilicate body. Variations in the waterglass to metakaolin ratio decreasing the nominative K/Al and Si/Al ratio produced about the same binder phase but led to a significant portion of unreacted metakaolin. Further silicate and aluminosilicate cements were synthesized based on rice husk-bark ash, slag, and combinations with slag and metakaolin. It is concluded that the formation and crosslinking of long silicate chains becomes crucial for gaining high mechanical strength and that the protection of the silicate chains becomes crucial for holding long time high strength. This protection is given in the presence of unresolved metakaolin and becomes more pronounced with the addition of significant amounts of CaO together with highly reactive SiO2 source material (Slag).",
author = "R{\"u}scher, {C. H.} and E. Mielcarek and J. Wongpa and F. Jirasit and W. Lutz",
year = "2010",
month = sep,
day = "27",
doi = "10.1002/9780470944103.ch3",
language = "English",
isbn = "9780470921913",
series = "Ceramic Engineering and Science Proceedings",
number = "10",
pages = "17--34",
booktitle = "Strategic Materials and Computational Design - A Collection of Papers Presented at the 34th International Conference on Advanced Ceramics and Composites",
edition = "10",
note = "Strategic Materials and Computational Design - 34th International Conference on Advanced Ceramics and Composites, ICACC ; Conference date: 24-01-2010 Through 29-01-2010",
}