engleski

Thermal analysis of sol-gel derived precursors for alkali activated materials

Alkali activated materials (AAM) are inorganic materials, but in comparison to traditional mineral binders, they do not set through the hydration reaction, instead they rather require activation solutions such as mixtures of sodium/potassium silicate solution and sodium/potassium hydroxide. The main property of AAM solid precursor is the availability of the main constituing units that build up the new material after activation. In this work the thermal analysis of different solid precursors obtained by the sol-gel method was investigated. For the synthesis different alkoxides (tetraethoxy silane and aluminium-tri-sec- butoxide), chelators (ethyl acetoacetate) and salts (aluminium nitrate nonahydrate) were used. Sol-gel synthesis enabled the preparation of amorphous solid precursors of high chemical homogeneity, which resulted in AAMs with good properties. Through simultaneous differential thermal and thermogravimetric analysis and powder X-ray diffraction characterisation it was possible to determine which thermal treatment conditions are necessary to sufficiently remove the organic residuals without compromising the amorphous state of the precursors. The analysis of the subsequently formed crystalline phase corroborate well with the predictions and suggest favourable setting of AAM.

alkali activated materials ; thermal analysis ; sol-gel method

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