The effect of fly ash on some surface characteristics and microstructure of beta-C2S

The effect: of the addition of fly ash (0-15 wt. \%) on the surface characteristics of beta-C2S and its microstructure was investigated using nitrogen adsorption at -196 degrees C together with scanning electron microscope (SEM) techniques. The results obtained revealed that the addition of fly ash up to 5 wt. \% increased the specific surface area by 32\% followed by a decrease of 34\% when the fly ash content was increased up to 15 wt. \%. SEM investigation showed that the hydrates produced form an outer shell which coats the fly ash particles.