Influence of Silica Fume Source on Crystallization of Xonotlite in a New Process Making Medium Density Ca-Silicate Based Products


Article Preview

This paper investigates the influence of different types of silica fume on the crystallization process of medium density calcium silicate based products. The products are formed by a new technology that consists of two steps. In the first step, a mixture containing calcium silicate hydrates (C-S-H) is formed by reaction of lime with special silicas at temperatures below 100°C. This mixture is then molded into boards by a filter-pressing technique. In the second step, the boards are treated in hydrothermal conditions enabling the conversion of the C-S-H into important contents of xonotlite (Ca6Si6O17(OH)2); this is the most stable calcium silicate hydrate phase at high temperatures. In order to make C-S-H in pressure less conditions, the use of reactive forms of silica is required. In this work we used silica fume as reactive silica. To understand the influence of the silica fume on the formation of xonotlite, several properties were studied, such as particle size, purity and specific surface area (BET). It was found that the particle size distribution and degree of agglomeration for the silica fume were the most important properties. A proper dispersion technique must be applied in order to break the silica fume agglomerates, forming particles small enough to react with dissolved lime and to form C-S-H phases that are able to be converted into xonotlite under hydrothermal conditions. Finally, it was also found that the formation of xonotlite is favored by the use of high purity silica fume.



Main Theme:

Edited by:

Gundars Mežinskis, Līga Grase, Ruta Švinka, Ilona Pavlovska, Jānis Grabis, Kęstutis Baltakys and Irina Hussainova




F. Marti-Montava et al., "Influence of Silica Fume Source on Crystallization of Xonotlite in a New Process Making Medium Density Ca-Silicate Based Products", Key Engineering Materials, Vol. 788, pp. 3-12, 2018

Online since:

November 2018




* - Corresponding Author

[1] S. Haastrup, M.S. Bødker, S. R, Hansen, D. Yu and Y. Yue, Impact of amorphous silica fume on the C-S-H phase formation in porous calcium silicates, Journal of Non-Crystalline Solids, 481 (2018) 556-561.


[2] J. J. Chen, J. J. Thomas, H. F. W. Taylor and H. M. Jennings, Solubility and Structure of Calcium Silicate Hydrate, Cement and Concrete Research, 34 (2004) 1499-1519.


[3] E. D. Rodriguez, L. Soriano, J. Payá, M. V. Borrachero and J. M. Monzó, Increase of the reactivity of densified silica fume by sonication treatment, Ultrasonics Sonochemistry, 19 (2012) 1099-1107.


[4] R. K. Iler, The Chemistry of Silica, Solubility, Polymerization, Colloid and Surface Properties, and Biochemistry, John Wiley& Sons, New York, (1979).

[5] D-Y. Lei, L-P. Guo, W. Sun, J. Liu, X. Shu and X-L. Guo, A new dispersing method on silica fume and its influence on the performance of cement-based materials, Construction and Building Materials, 115 (2016) 716-726.


[6] S. Haastrup, D. Yu and Y. Yue, Impact of surface impurity on phase transitions in amorphous silica fume, Journal of Non-Crystalline Solids, 450 (2016) 42-47.


[7] K. Baltakys, R. Jauberthie, R. Siauciunas, R. Kaminskas, Influence of modification of SiO2 on the formation of calcium silicate hydrate, Materials Science-Poland, 25 (2007) 3.

[8] T. Mitsuda, J. Saito and E. Hattori, Influence of starting materials on the hydrothermal formation of xonotlite at 180˚C, Proceedings of 1st International Symposium on Hydrothermal Reactions, Japan (1982).

[9] D.J. Belton, O. Deschaume and C.C. Perry, An overview of the fundamentals of the chemistry of silica with relevance to biosilicification and technological advances, Federation of European Biochemical Societies Journal, 279 (2012) 1710-1720.


[10] M. Seipenbusch, S. Rothenbacher, M. Kirchholf, H.J. Schmid, G. Kasper and A.P. Weber, Interparticle forces in silica nanoparticle agglomerates, Journal of nanoparticle research, 12 (2010) 2037-(2044).


[11] S.P. Yeap, Permanent agglomerates in powdered nanoparticles: Formation and future prospects, Powder Technology, 323 (2018) 51-59.


[12] A. Kariman, V.V. Basava Rao, M. Farjpourlar, Fluidization characteristics of nano particles with the assist of stirrer, Journal of Applied Physics, 5 (2013) 24-27.


[13] F. Martí-Montava, A. Opsommer, D. García-Sanoguera, New method for making medium density Ca-silicate based products and influence of the used raw materials, Proceedings of 60th International Colloquium on Refractories, Germany, (2017).

[14] D. Martínez-Velandia, J. Payá, J. Monzó, M. V. Borrachero, Effect of the sonication on the reactivity of silica fume in Portland cement mortars, Advances in Cement Research, 23 (2011) 23-31.


[15] D.R.G. Mitchell, I. Hinczak, R. A. Day, Interaction of silica fume with calcium hydroxide solutions and hydrated cement pastes, Cement and Concrete Research, 28 (1998) 1571-1584.


[16] D.S. Snell, Review of synthesis and properties of tobermorite, C-S-H (I) and C-S-H gel, Journal of the American Ceramic Society, 58 (2006) 292-295.

[17] L. Black, K. Garbev, A. Stumm, Structure, bonding and morphology of hydrothermally synthesized xonotlite, Advances in Applied Ceramics, 108 (2009) 137-144.


[18] S.A.S. El-Hemaly, T. Mitsuda, H.F.W. Taylor, Synthesis of normal and anomalous tobermorites, Cement and Concrete Research, 7 (1977) 429-438.


[19] 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 Geology, 167 (2000) 129-140.


[20] C.F. Chan, T. Mitsuda, Formation of 11 Å tobermorite from mixtures of lime and colloidal silica with quartz, Cement and Concrete Research, 8 (1978) 135-138.


[21] T. Mitsuda, K. Sasaki, H. Ishida, Phase evolution during autoclaving process of aerated concrete, Journal of American Ceramic Society, 75 (1992) 1858-1863.


[22] K. Baltakys, R. Siaciunas, The influence of γ-Al2O3 and Na2O on the formation of calcium silicate hydrates in the CaO-quartz-H2O system, Materials Science Poland, 25 (2007) 1.

[23] K. Matsui, J. Kikuma, 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).