Content of Aluminium Hydroxide in Lime-Silica Composite and its Influence on Tobermorite Formation

Abstract:

Aerated concrete is lightweight building material with excellent thermos-technical properties compared to its strengths, easy workability and economic efficiency. It is material with long tradition of manufacturing since 1924 but its potential is yet possible to be extended. Since the beginning pure ingredients such as lime and silica sand has been used. Nowadays we are looking for ways to replace these expensive raw materials with cheaper alternatives. One of the most important mechanical properties of each material is its strength. In case of aerated concrete the bearer of strength is mineral tobermorite. It is created by reaction of silicon oxides and lime at hydrothermal conditions. It belongs to the group of calcium hydrosilicates with chemical formula Ca₅Si₆O₁₆(OH)₂·4H₂O. Main goal of this paper is proposal for modification of the raw materials composition and autoclave regime of aerated concrete using aluminium hydroxide in order to improve final mechanical properties and mineralogical composition.

• Periodical: Materials Science Forum (Volume 916)
• Pages: 195-199
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.916.195
• Online since: March 2018
• Authors: Jindřich Melichar*, Vit Černý, Jan Fleischhacker, Rostislav Drochytka
• Keywords: Aerated Concrete, Aluminium Hydroxide, Silica Sand, Tobermorite, X-Ray Powder Diffraction

References

[1] K. MATSUI, J. KIKUA, M. TSUNASHIMA,T. ISHIKAWA, S. MATSUNO, A. OGAWA, M. SATO: In situ time – resolved X – ray diffraction of tobermorite formation in autoclaved aerated concrete: Influence of silica source reactivity and Al addition, Cement and Concrete Research 41, 2011, p.510.

DOI: 10.1016/j.cemconres.2011.01.022

[2] D.S. KLIMESCH, A. RAY: Effects of quartz particle size on hydrogarnet formation during autoclaving at 180 °C in the CaO-Al2O3-SiO2-H2O system, Cement and Concrete Research 28, 1998, p.1309 – 1316.

DOI: 10.1016/s0008-8846(98)00112-4

[3] K. LUKE: Phase studies of puzzolanic stabilized calcium silicate hydrates at 180 °C, Cement and Concrete Research 34, 2004, p.1725 – 1732.

DOI: 10.1016/j.cemconres.2004.05.021

[4] D.S. KLIMESCH, A. RAY: Effects of quartz particle size and kaolin on hydrogarnet formation during autoclaving, Cement and Concrete Research 28, 1998, p.1317 – 1323.

DOI: 10.1016/s0008-8846(98)00111-2

[5] C.A. RÍOS, C.D. WILLIAMS, M.A. FULLEN: Hydrothermal synthesis of hydrogarnet and tobermorite at 175 °C from kaolinite and metakaolinite in the CaO – Al2O3 – SiO2 – H2O system: A comparative study, Applied Clay Science 43, 2009, p.228 – 237.

DOI: 10.1016/j.clay.2008.09.014

[6] W. NOCUŃ-WCZELIK: Effect of some inorganic admixtures on the formation and properties of calcium silicate hydrates produced in hydrothermal conditions, Cement and Concrete Research 27, 1997, p.83 – 92.

DOI: 10.1016/s0008-8846(96)00191-3

[7] S. SHAW, S.M. CLARK, C.M.B. HENDERSON: Hydrothermal formation of the calcium silicate hydrates, tobermorite (Ca5Si6O16(OH)2·4H2O) and xonotlite (Ca6Si6O17(OH)2): an in situ synchrotron study, Chemical geolgy 167, 2000, p.129 – 140.

DOI: 10.1016/s0009-2541(99)00205-3

[8] K. BALTAKYS, R. SIAUCIUNAS: The influence of γ-Al2O3 and Na2O on the formation of calcium silicate hydrates in the CaO – quartz – H2O system, Materials Science-Poland, vol. 25, No. 1, 2007, p.185 – 198.

[9] J.E. OH, S.M. CLARK, P.J.M. MONTEIRO: Does the Al substitution in C-S-H (I) change its mechanical property ?, Cement and Concrete Research 41, 2011, pp.102-106.

DOI: 10.1016/j.cemconres.2010.09.010