The Effect of Synthesis Parameters on the Structure and Properties of Metakaolin Based Geopolymers
In the present work the geopolymerisation of metakaolin under varying conditions is investigated.The experimental part comprises the following parts: i) the synthesis of metakaolin based geopolymers and the investigation of the effect of the Si/Al ratio and the kind of alkali ion on the development of the compressive strength and ii) the characterization of the geopolymers by means of XRD, FTIR and SEM. As it is found the development of the compressive strength is strongly affected by the Si/Al ratio in the starting material and the kind of alkali metal, with the maximum being 70.1 MPa for a Si/Al ratio equal to 2.00. The Na- geopolymers show higher compressive strength compared to the NaK-geopolymers. Finally, low Si/Al ratios favour the formation of crystalline compounds (mainly zeolites), while Si/Al ratios higher than 1.5 lead to the formation of amorphous materials.
Luís Guerra ROSA and Fernanda MARGARIDO
A. Tsitouras et al., "The Effect of Synthesis Parameters on the Structure and Properties of Metakaolin Based Geopolymers", Materials Science Forum, Vols. 636-637, pp. 149-154, 2010