Performance of Metakaolin-Fly Ash Geopolymer at Hydrothermal Condition

This paper investigated the effects of metakaolin-fly ash ratio on the performances of geopolymer through compressive strength testing,MIP,XRD and SEM. The increase of fly ash content led to the increment of mechanical strength of the geopolymer. The compressive strength of alkali activated fly ash specimens were 64. 7% and 116. 0% higher than the metakaolin geopolymer cured for 3 d and 7 d at 50℃,respectively. The results of MIP and SEM showed that the addition of fly ash made the structure more compact. The amorphous phase formed in the alkali-activated fly ash geopolymer, related to the featureless hump at 25° ~ 35° in XRD patterns,was beneficial for the performance of metakaolin-fly ash geopolymer.