Title:
Control of Physical Deterioration of Foamed Geopolymers Exposed to High Temperature
Author(s):
Zhuguo Li
Publication:
Symposium Paper
Volume:
362
Issue:
Appears on pages(s):
179-188
Keywords:
crack, expanded perlite particle, fire resistance, foamed geopolymer, stone powder, shrinkage
DOI:
10.14359/51740882
Date:
6/5/2024
Abstract:
Foamed geopolymers possess excellent fire resistance similar to ordinary geopolymers and can also provide good thermal insulation when using lightweight aggregates, making them ideal for fire-resistant coatings. However, foamed geopolymers are susceptible to significant and uneven shrinkage, which can result in cracks and breakage when heated due to the dehydration of the weakly bound water in the C-A-S-H or N-ASH gels. To address this issue, this study incorporated the expanded perlite particles (EPP) and replaced a portion of fly ash with crushed stone powder (CSP) in a ground granulated blast furnace slag/fly ash-based geopolymer that was foamed using fine metallic silicon powder. The EPP and CSP acted as inactive precursors to form a stable particle skeleton with a continuous gradation in the foamed geopolymers. Experimental results indicate that the suitable inclusion of CSP and EPP effectively mitigated geometrical deterioration and cracking under elevated temperatures. The foamed geopolymers with these additives showed no warping or cracking, even as they decreased in dimension and bulk density when heated on a one-side surface. It is considered that continuous gradation of CSP and EPP particles formed a stable particle skeleton within the foamed geopolymer to effectively diminish the shrinkage caused by the thermal decomposition of gels.
Related References:
1. Davidovits, J., 2015, “Geopolymer chemistry & Application (4th edition)”, Institute Geopolymer, France, 357-409.
2. Li, Z., and Ikeda, K., 2023, “Influencing factors of sulfuric acid resistance of Ca-rich alkali-activated materials”, Materials, 16(6), 2473, doi: 10.3390/ma16062473
3. Rickard, W. D.A., Temuujin, J., and Riessen, A.V, 2012, “Thermal analysis of geopolymer pastes synthesised from five fly ashes of variable composition”, Journal of Non-Crystalline Solids, 358, 1830-1839, doi: 10.1016/j.jnoncrysol.2012.05.032
4. Zhao, R., and Sanjayan, J.G., 2011, “Geopolymer and portland cement concretes in simulated fire”, Magazine of Concrete Research, 63, 163-173, doi: 10.1680/macr.9.00110
5. Sakkas, K., Nomikos, P., Sofianos, A., and Panias, D., 2014, “Sodiumbased fire resistant geopolymer for passive fire protection”, Fire and Materials, 39(3), 259 – 270, doi: 10.1002/fam.2244
6. Hlav´aˇcek, P., ˇSmilauer, V., ˇSkvara, F., Kopeck´y, and L., ˇSulc, R., 2015, “Inorganic foams made from alkali-activated fly ash: Mechanical, chemical and physical properties”, Journal of the European Ceramic Society, 35(2), 703-709, doi: 10.1016/j.jeurceramsoc.2014.08.024
7. Watolla, M.B., Gluth, G.J.G., Sturm, P., Rickard,W.D.A., Kruger, S., and Schartel, B., 2017, “Intumescent geopolymer-bound coatings for fire protection of steel”, Journal of Ceramic Science and Technology, 8 (3), 351–364, DOI: 10.4416/JCST2017-00035
8. Li, Z., and Ikeda, K., 2018, “Porous geopolymer materials”, Japan patent JP6430268.
9. Tian, Q., and Li, Z., 2016, “Fundamental study on fire-proofing material using porous geopolymer”, Summaries of Technical Papers of Annual Meeting, Architectural Institute of Japan, 1499-1500.
10. Sasaki,W., Li, Z., Sugihara, D., and Ryuda, Y., 2017, “Development of fire-proof covering material of porous geopolymer”, Proceedings of Annual Research Meeting Chugoku Chapter, Architectural Institute of Japan, 40, 45-48.
11. Yashiro, D., Shin, D., Shudo. S., and Miyashiro, R., 2020, “Physical and chemical changes of hardened geopolymer under high temperature”, Proceedings of the Japan Concrete Institute, 42, 1792-1797.
12. Iwama, Y. and Li, Z., 2022, “Study on geopolymer using perlite stone powder”, Proceedings of the Japan Concrete Institute, 44, 1102-1107, 2022.