Mechanism of Silica Fume in Suppressing Alkali-Silica Reaction of Concrete：Interfacial Transition Zone Concerns

Abstract:

The composition and structure of the interfacial transition zone (ITZ) in concrete were investigated to analyze the mechanism of silica fume in suppressing alkali-silica reaction (ASR). Alkali active concrete specimens with varying addition of silica fume were prepared for the experiment. Changes of compositions and pore structures at ITZ and the elements distribution across ITZ were analyzed by SEM and SEM-BSE. The expansion of the corresponding mortar bar was also measured. The results show that the accumulation of element of alkali metal occurred at ITZ in alkali active concrete without silica fume, while the characteristics of the ITZ are basically similar to those in conventional concrete. By addition of silica fume, the ITZ in alkali active concrete are changed and have the following features: disappearance of the accumulation, occurrence of the C-S-H gel with a lower CaO/SiO2 ratio, decrease in crystal phases of Ca(OH)2 and ettringite, and in porosity. These changes account for the mechanism of Silica fume in suppressing ASR.

• Periodical: Advanced Materials Research (Volumes 450-451)
• Pages: 676-682
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.450-451.676
• Online since: January 2012
• Authors: Bing Gen Zhan, Quan Wang, Wan Liang Zhou, Hong Yu Sheng
• Keywords: Alkali-Silica Reaction, Concrete, Interfacial Transition Zone, Mechanism, Silica Fume (SF)

References

[1] Hooton, R: ACI Materials Journal, 1993. 90: 143-151

[2] Malvar, L.J., et al: ACI Materials Journal, 2002. 99(5): 480-489.

[3] Chengzhi, Z. and W. Aiqin:Journal of Wuhan University of Technology-Mater, 2008. 23(1): pp.16-19.

[4] Zhongyi Y. : Design of Hydropower Station, 2000. 16(2): 105-112.(In Chinese)

[5] Ollivier, J.P., Maso J.C., and Bourdette B:Advanced Cement Based Materials, 1995. 2(1): 30-38.

DOI: 10.1016/1065-7355(95)90037-3

[6] Detwiler, R.J., et al:Concrete International, 2001. 23(11): 50-58.

[7] Kjellsen, K.O., Detwiler R.J., and Gjorv O.E:Cement and Concrete Research, 1990. 20(2): 308-311.

[8] Scrivener, K.L. and P.L. Pratt. Proceedings of the 8th International Congress of the Chemistry of Cement. Rio de Janeiro. 1986: 466-471

[9] Xiaohai Wang, Compositions and Structures of Hardened Concrete in Alkali Circumstances. 2009, Dissertation of Hefei University of Technology. (In Chinese)

[10] Bensted J., Barnes P., Structure and Performance of Cements, 2nd edition, 2002, Spon Press.

[11] Hong, S.Y. and Glasser F.P: Cement and Concrete Research, 1999. 29(12): 1893-1903.