ROLE OF THE MORPHOLOGY AND THE DEHYDROXYLATION OF METAKAOLINS ON GEOPOLYMERISATION

Two commercial metakaolins were tested during partial geopolymerisation with potassium silicate to emphasise 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...

Full description

Saved in:
Bibliographic Details
Published in:Applied clay science 2010-01, Vol.50 (4), p.538-545
Main Authors: Medri, V, Fabbri, S, Dedecek, J, Sobalik, Z, Tvaruzkova, Z, Vaccari, A
Format: Article
Language:English
Subjects:
Curing
Demand
Dispersion
Heating
Infrared radiation
Macrostructure
Morphology
Specific surface
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Two commercial metakaolins were tested during partial geopolymerisation with potassium silicate to emphasise 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 geopolymerisation was verified by SEM and N2 adsorption (BET), FTIR and 27Al 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 geopolymerisation conditions than the fine dispersed lamellar one, thus giving rise to very different micro- and macrostructures of the partially geopolymerised samples. IR heating seemed to increase the geopolymerisation degree slightly, while MW heating induced the fast evaporation of the water, forming porous samples.
ISSN:0169-1317