engleski

Application SAXS method in characterisation of geopolymer

This study investigated the influence of different concentrations of NaOH (8, 10 and 12 mol/dm3) in the solution of alkali activator (AA) as well as the impact of varying the ratio of AA and fly ash (FA) (AA/FA=0.3, 0.35 and 0.40) on the geopolymerisation processes in the geopolymer paste system. Activation of geopolymerisation was carried out in sealed polyethylene moulds for 24 hours at 85 oC. Geopolymerisation efficiency was monitored by determining compressive strength after 1, 7, 14 and 28 days at room temperature fostering carried out after activation. The results indicate that it is an extremely important factor, which largely determines the mechanical properties of the fraction reactive phase, the ratio of AA/FA, the proportion of water and especially the concentration of NaOH and dissolved silicate. The highest values of developed compressive strength were in systems with c(NaOH) = 8 and 10 mol/dm3 and the ratio of AA/FA = 0, 3 – 0, 4. The lowest compressive strength values were observed in samples with c(NaOH) = 12 mol/dm3 for all three AA/FA ratios. The paper also presents the results of research on thermal stability, structural reorganisation, crystallinity, developed microstructure, particle size obtained by using TG/DTG-DTA, XRD, FTIR, SEM and SAXS.

fly ash; geopolymer; alkali activation; SAXS; XRD

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