Kinetic Study of the Thermal Dehydration of Fly Ash Filled Geopolymers.

Metakaolin‐based geopolymers at different percentage of fly ash (namely 25, 50, and 70% wt) are prepared by using recycled fly ash, aiming at reducing the amount of waste to be treated or disposed in landfills. The synthesized samples are subjected to the thermogravimetric analysis (TGA) to investigate the kinetics of dehydration process. To this purpose, TGA data are treated by the Kissinger method to calculate the apparent activation energy (Ea) of dehydration. The obtained kinetics parameters are discussed and compared with each other and with those obtained for the control geopolymer. A decrease in Ea values of the filled geopolymers is found, showing the effect of the fly ash in reducing the dehydration rate. A classification among the samples at different percentage of fly ash is also drawn up, showing the reaching of a plateau at percentage above the 50 wt%. [ABSTRACT FROM AUTHOR]