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  • Foaming of alkali activated materials [Elektronski vir]
    Ducman, Vilma ...
    Alkali-activated materials (hereinafter: AAM), often also called geopolymers, are obtained by process where materials rich with glassy aluminosilicate are dissolved in alkali media. After the ... dissolution and transport of the components (Al, Si) then through poly-condensation of the Al and Si an aluminosilicate network is formed. Suitable precursors for AAM are different waste materials (fly ash, bottom ash, bio-based ashes, various slags, waste glass), but also thermally activated clay (metakaolin), and natural pozzolan (e.g. volcanic ash). Many products, which could replace traditional building products, such as concrete or ceramic, can be obtained by the alkali activation process. In recent years AAM foams have attracted much attention since they are inorganic, non-combustible material for whose production waste materials can be utilized, and the process takes place at relatively low temperature. Foams are formed by adding either preform organic foams and/or by adding of foaming agent which reacts with a slurry or it decomposes into a gas which remains trapped inside the structure. To obtain a stable, uniformly porous structure many parameters play role in the process, and have been subject of our investigations. The most important one is type of precursors and the influence of their chemical compositions, part of amorphous phase and particle size on reactivity and mechanical parameters. In our research precursors like fly ash and slags have been used and activated by sodium water glass and NaOH, as well as potassium water glass and KOH. Optimal curing regime for our systems has been defined, i.e. heating at slightly elevated temperature (between 70 and 90 °C). To obtain foamed AAM foaming agents such as Al powders, H2O2 or NaOCl have been added and properties like porosity, pore size distribution and mechanical properties of so obtained foams have been studied in order to produce tailor made foams with densities down to 0.3 g/cm3.
    Source: Book of abstracts [Elektronski vir] (Str. 131)
    Type of material - conference contribution ; adult, serious
    Publish date - 2019
    Language - english
    COBISS.SI-ID - 2488679

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