Hydration Activity of Silica Fume and its Effect on the Structure of C-S-H Gel

Abstract:

Hydration activity of silica fume(SF) and its effect on the structure of C-S-H gel in silica fume-cement (SFC)pastes was studied by FTIR and 29Si MAS NMR combined with deconvoluton technique, respectively. The experimental results indicate that the cement of 48% and the SF of 41% can react in the paste with SF replacement for cement was 10% by weight and the average chain length (ACL) of SiO4 and/or AlO4 tetrahedra in C-S-H was 3.0 at 3d. At 120d, the cement of 65% and the SF of 96% could react, and the ACL of C-S-H was 3.7, which was higher than that in the plain cement paste (ACL was 3.1). In the highly alkaline environment of the cement paste, pozzolanic reaction of silica fume can potentially occur in two ways, the monosilicate formed after the structure of silica fume were broken can combine with Ca cations to form C-S-H directly. Moreover, these chemical species can also connect C-S-H dimers into highly polymerized C-S-H and increase the ACL of C-S-H.

• Periodical: Applied Mechanics and Materials (Volumes 275-277)
• Pages: 2084-2087
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.275-277.2084
• Online since: January 2013
• Authors: Lei Wang, Zhen He, Jianjun Yan
• Keywords: Activity, C-S-H, Hydration, NMR, Structure

References

[1] JJ Thomas, JJ Chen, HM Jennings:. Chem Mater, Vol. 15 (2003) , p.3815.

[2] Y. W Liu: Constr. Build. Mater. Vol. 21(2007) , p.974.

[3] X. D Cong, R.J. Kirkpatrick: Advn. Cem. Bas. Mat . Vol. 3 (1996) , p.149.

[4] G.K. Sun, J. F. Young., R.J. Kirkpatrick : Cem. Concr. Res. Vol. 36(2006) , p.24.

[5] I.G. Richardson: Cem. Concr. Res. Vol. 38(1999) , p.153.

[6] I.G. Richardson: Cem. Concr. Res. Vol. 29(1999) , pp.1-138.

[7] Wang K.S., Lin K.L., Z.Q. Huang : Cem. Concr. Res. Vol. 31(2001) , p.99.

[8] Lin K.L., C. Y Lin: Cem. Concr. Res. Vol. 35 (2005) , p. (2003).

[9] Andersen. Jakobsen, Anderson S.D., J.J. Hans: Cem. Concr. Res. Vol. 34 (2003) , p.862.