Alkali-Activation Reactivity and Al Environment of Chemosynthetic Al2O3–2SiO2 Powders


Article Preview

In this study, pure Al2O3-2SiO2 powders for a geopolymer were prepared by a sol-gel method, alkali-activation tests and alkali-dissolvability of the powders were carried out, and structure of the powders and alkali-activated products was investigated by 29Si and 27Al MAS NMR and SEM. Results showed that higher alkali-activation reactivity (higher compressive strengths of alkali-activated products) appeared in the powders heat-treated between 600-800 °C and alkali-dissolvability trend was different from that of alkali-activation tests. There were clear correlations between microstructure of alkali-activated products and alkali-activation reactivity and Al environment of the powders. It was found that high strength was related to a dense, fine grained microstructure. Such a structure was found in the alkali-activated products synthesized with the powders with high 5-coordinated Al contents. In addition, the peaks attributed to 5-coordinated Al were strengthened with the rise of heat-treated temperature of the powders.



Advanced Materials Research (Volumes 79-82)

Edited by:

Yansheng Yin and Xin Wang




G. J. Zheng et al., "Alkali-Activation Reactivity and Al Environment of Chemosynthetic Al2O3–2SiO2 Powders", Advanced Materials Research, Vols. 79-82, pp. 2079-2082, 2009

Online since:

August 2009




[1] J. Davidovits: J. Thermal. Anal. Vol. 37(1991), p.1633.

[2] J. Rocha, J. Klinowski: Angew. Chem. Int. End. Eng. Vol. 29(1990), p.553.

[3] J. Rocha, J. Klinowski: Phys . Chem. Minerals. Vol. 17(1990), p.179.

[4] H. He, C. Hu, J. Guo and H. Zhang: Chinese J. geochem. Vol. 14 (1995), p.78.

[5] C. Wei , D. Yang , Y. Li, A. Mikuni: ACTA MINERALOGICA SINICA Vol. 25 (2005), p.197(in Chinese).