Effects of Activators on Compressive Strength of Fly Ash-Based Geopolymers


Article Preview

The effects of different activators on compressive strength of fly ash-based geopolymers have been studied. It is discovered that, alkali solution doesn’t have obvious effect, while Na2SiO3 solution has visible effect, the strength of samples rise with the increase of Na2SiO3 solution concentration. The effect of K2SiO3 solution is more obvious than Na2SiO3 solution, the strength of samples tend to first increase and then decrease with the increase of K2SiO3 solution concentration. The K2SiO3 solution with concentration of 2 M is the best activator to prepare geopolymers, which has compressive strength of 28.8 MPa at 28 d. When water glass are used as activators, the best modulus and solid content for Na-water glass (Na2O•nSiO2) are 1.2 and 32%, respectively. On this condition the sample’s compressive strength at 28 d is 38.9 MPa. However crystal calcium oxide is harmful for the compressive strength development, which is different with the conclusion accepted abroad.



Advanced Materials Research (Volumes 197-198)

Edited by:

Huaiying Zhou, Tianlong Gu, Daoguo Yang, Zhengyi Jiang, Jianmin Zeng




D. M. Wang et al., "Effects of Activators on Compressive Strength of Fly Ash-Based Geopolymers", Advanced Materials Research, Vols. 197-198, pp. 830-836, 2011

Online since:

February 2011




[1] DAVIDOVITS J. Ancient egyptian pyramids-concrete or rock[J]. Concrete Intentional, 1987 , 9 (12): 28-39.

[2] Van JAARSVELD J S G, Van DEVENTER J S J, LORENZEN L. The potential use of geopolymeric materials to immobilize toxic metals  Part I  Theory and applications[J]. Miner Eng , 1997, 10 (7): 659-669.

DOI: https://doi.org/10.1016/s0892-6875(97)00046-0

[3] DAVIDOVITS J. Geopolymers cement to minimize carbon dioxide greenhouse warming[J]. Ceramic Transactions, 1993, 37: 165–182.

[4] XU H, Van DEVENTER J S J, LU KEY G C. Effect of alkali metals on t he preferential geopolymerization of stilbite/kao-linite mixtures[J]. Ind Eng Chem Res, 2001, 40 (17): 3749-3756.

DOI: https://doi.org/10.1021/ie010042b

[5] CIOFFI R , MAFFUCCI L, SANTORO L. Optimization of geopolymers synt hesis by calcinations and polycondensation of a kaolintic residue [J]. Resources, Conservation and Recycling, 2003, 40: 27-38.

DOI: https://doi.org/10.1016/s0921-3449(03)00023-5

[6] XU H, Van DEVENTER J S J. The geopolymerization of alumino2silicate minerals [J]. International Journal of Minerals and Processing, 2000, 59(3): 247-266.

[7] Hua Xu, Van Deventer J.S.J. The geopolymerisation of alumino-silicate mineral. International Journal of Mineral Processing, 2000, (59): 297.

DOI: https://doi.org/10.1016/s0301-7516(99)00074-5