engleski

Preparation of unconventional environmentally friendly inorganic binders

Fly ash is an industrial waste material generally used in the cement industry as a partial replacement for cement (in CEM III types) an as an additive in the concrete/mortar preparation. The reactivity of the amorphous phase (pozzolanic reaction) arising from fly ash improves properties of the cement composite, such as the resistance against aggressive environment influences (sulphate or chloride). Disadvantages of using fly ash in the cement industy are very low early strength and the limited amount and type of fly ash that can be added to the mixture. Recently, another form of cementitous materials called geopolymers has been developed. Geopolymers are generally synthesized by activation of raw materials based on alumosilicate composition such as fly ash, metakaoline and/or blast furnace slag with alkaline solution (alkaline hydroxide and silicate solution). Dissolving silica and alumina species from raw materials require a high pH and certain amount of soluble silica that must be added to the raw material in the form of alkaline solution. A combination of sodium (potassium) silicate and sodium (potassium) hydroxide is usually used as the alkaline activator. In this paper will be presented application time resolved SAXS measuring in the purpose of following the process of geopolymerization.

fly ash; geopolymer; alkali activation; SAXS; XRD

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