Role of the morphology and the dehydroxylation of metakaolins on geopolymerization

0357802 - ÚFCH JH 2011 RIV NL eng J - Journal Article
Medri, V. - Fabbri, S. - Dědeček, Jiří - Sobalík, Zdeněk - Tvarůžková, Zdenka - Vaccari, A.
Role of the morphology and the dehydroxylation of metakaolins on geopolymerization.
Applied Clay Science. Roč. 50, č. 4 (2010), s. 538-545. ISSN 0169-1317. E-ISSN 1872-9053
Institutional research plan: CEZ:AV0Z40400503
Keywords : metakaolin * geopolymerization * microstructure
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 2.303, year: 2010

Two commercial metakaolins were tested during partial geopolymerization with potassium silicate in order to emphasize the different surface reactivities. Both manual and short-term mechanical stirring were used for slurry preparation while radiation. Infrared and microwave heating were used for curing. The metakaolins had similar compositions and specific surface areas but different morphologies and dehydroxylation degrees due to different calcination kiln technologies. The degree of geopolymerization was checked by SEM and N-2 adsorption (BET) FTIR and Al-27 MAS NMR spectroscopy. While the dehydroxylation degrees were different the metakaolins had similar reactivity. The metakaolin powder with rounded agglomerates and lower water demand was more sensitive to the various geopolymerization conditions than the fine dispersed lamellar one thus giving rise to very different micro- and macrostructures of the partially geopolymerized samples.
Permanent Link: http://hdl.handle.net/11104/0195997