In this paper, an experimental study on the thermo-mechanical properties of fly ash-metakaolin blend geopolymers is presented. Visual observations, density and mass loss and compression test were conducted on geopolymers heated in a furnace at 200 °C, 400 °C, 600 °C, 800 °C and 1000 °C with a heating rate of 10 °C/min and soaking time of 1 hours. Fly ash-metakaolin blend geopolymers possessed excellent strength of 54.7MPa at ambient temperature and degraded 23.4% to 41.9MPa when exposed 200?C. The tested result show that the geopolymer can perform good residual strength (up to 23.2MPa) after 600?C. The strength of geopolymers decreased to 5.8MPa with increasing temperature up to 800?C. Even so, the geopolymers could withstand high temperature and remained intact. The higher mass loss due to the liberation of water from the surface, led to significant strength degradation in fly ash-metakaolin blend geopolymers. However, geopolymer gels exhibited structural stability at 1000°C, since at this temperature it promotes the reaction of the residue fly ash and metakaolin in the geopolymer samples, leading to a strength increase to 9.1MPa Employing blend fly ash and metakaolin as a precursor in the geopolymers helped to minimize the disruption effect caused by high temperature exposures.
