Siberian Federal University

Of the industrial by-products, fly ash (FA) from coal combustion is of the greatest interest as a component of geopolymer binders. Using FA to reduce the proportion of cement or replace it completely contributes to savings in the production of building materials and improves the environmental situation. Specimens of geopolymer binders (GB) obtained on the basis of two industrial fractions of high-calcium fly ash of similar chemical composition, differing in dispersion and phase composition, were studied. The factors influencing the thickening time of the geopolymer mortar and the strength of the samples with a curing time of 28–90 days were determined. It was found that the value of the compressive strength (20–27 MPa) is 3 times higher for the fraction with a smaller particle size and a high content of Ca- silicate glass. It was determined that in the composition of the geopolymer binder, a large fraction with a high content of the CaO phase allows obtaining samples with a strength 2.7–2.9 times higher than that of cement technology due to interaction with the silicate component of the reagent