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http://dx.doi.org/10.4334/JKCI.2006.18.4.449

Strength Development and Hardening Mechanism of Alkali Activated Fly Ash Mortar  

Jo, Byung-Wan (Dept. of Civil Engineering, Hanyang University)
Park, Min-Seok (Dept. of Civil Engineering, Hanyang University / Structures Research Group of Highway Transportation Technology Institute, Korea Highway Corporation)
Park, Seung-Kook (Dept. of Civil Engineering, Hanyang University)
Publication Information
Journal of the Korea Concrete Institute / v.18, no.4, 2006 , pp. 449-458 More about this Journal
Abstract
The discharge of fly ash that is produced by coal-fired electric power plants is rapidly increasing in Korea. The utilization of fly ash in the raw materials would contribute to the elimination of an environmental problem and to the development of new high-performance materials. So it is needed to study the binder obtained by chemically activation of pozzolanic materials by means of a substitute for the cement. Fly ash consists of a glass phase. As it is produced from high temperature, it is a chemically stable material. Fly ash mostly consists of $SiO_2\;and\;Al_2O_3$, and it assumes the form of an oxide in the inside of fly ash. Because this reaction has not broken out by itself, it is need to supply it with additional $OH^-$ through alkali activators. Alkali activators were used for supplying it with additional $OH^-$. This paper concentrated on the strength development according to the kind of chemical activators, the curing temperature, the heat curing time. Also, according to scanning electron microscopy and X-Ray diffraction, the main reaction product in the alkali activated fly ash mortar is Zeolite of $Na_6-(AlO_2)_6-(SiO_2)_{10}-12H_2O$ type.
Keywords
fly ash; alkali activator; strength development; reaction products; hardening mechanism;
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