Abstract
Chemical properties of geopolymers were evaluated from the reduction of fly ash particle size by grinding. X-ray diffraction determined that at early curing ages new crystalline phases appear in the matrix of the geopolymer and they remain for 28 days, with increases in intensities up to 60%. In Fourier transform infrared spectroscopy, displacements were identified in the main band of the geopolymers at higher wavenumbers, attributed to the greater rigidity in the structures of the aluminosilicate gel due to the increase of the reaction products in the geopolymers obtained through fly ashsubjected to previous grinding, which is observable in the geopolymers matrix. Results indicate that the reduction of fly ash particle size by grinding has an influence on the chemical properties of geopolymers.
Highlights
Current research by the scientific-technical community looks for alternative solutions to problems related to energy consumption and CO2 emissions.Global infrastructure demands require massive concrete and cement production, causing a significant negative environmental impact since its production is responsible for 5–7% of global anthropogenic CO2 emissions [1,2,3]
Through FT-IR it is demonstrated that Fly ash (FA) with finer particles produce high reactivity indexes in the geopolymers and, an increase in the reaction product of the alkaline aluminosilicate amorphous gel
The largest ones are concentrated in G3-14 and G3-28, and are up to 50% more intense than those in group G1, which can be attributed to a greater development of crystallinity in its phases [41], mainly due to a greater reactivity of the FA, because of the increase of the specific surface area induced by the reduction of particle size by grinding, which causes the weakening of Si-O and Al-O bonds and promotes the incorporation of soluble Si and Al in the crystalline chain
Summary
Current research by the scientific-technical community looks for alternative solutions to problems related to energy consumption and CO2 emissions. The chemical composition in mass is largely related to the kinetics of the geopolymer matrix; FA reactivity and the geopolymers chemical behavior depend on the particle sizes and surface area [26,27] The activation of these materials is promoted by mechanical means, such as grinding, where results that favor geopolymerization are obtained at low curing temperatures. Through FT-IR it is demonstrated that FA with finer particles produce high reactivity indexes in the geopolymers and, an increase in the reaction product of the alkaline aluminosilicate amorphous gel. This produces an increase in compressive strength [28,29]. The influence of three different particle sizes of Mexican FA were comparatively studied in the physicochemical behavior of the geopolymers, using XRD, FT-IR, and SEM
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