Produção Nacional
Revisado por pares
Assessment of mechanical and microstructural properties of geopolymers produced from metakaolin, silica fume, and red mud
2020; Wiley; Volume: 18; Issue: 1 Linguagem: Inglês
10.1111/ijac.13635
ISSN1744-7402
AutoresBeatryz Cardoso Mendes, Igor Klaus Rocha Andrade, José Maria Franco de Carvalho, Leonardo Gonçalves Pedroti, André de Oliveira Júnior,
Tópico(s)Recycling and utilization of industrial and municipal waste in materials production
ResumoAbstract Geopolymers have been studied as viable alternative to traditional Portland cement‐based products, given the use of industrial by‐products as raw materials. This work evaluated the mechanical and microstructural properties of geopolymeric mortars produced with sodium hydroxide solution, metakaolin, silica fume, and red mud. The mixtures were produced by means of dosages with different molar ratios and curing conditions. The raw materials were characterized by granulometry, chemical, mineralogical, and thermal analysis. The characterization of mortars was performed by scanning electron microscopy (SEM) and axial compressive strength tests. The precalcination at 850°C of the red mud was sufficient to make it more reactive and suitable for use in geopolymers. Noteworthy, the best mechanical strengths of metakaolin mortars for curing at 50°C, and with the lowest SiO 2 /Al 2 O 3 ratios. In the mortars with incorporated red mud, there was a decrease of strength at thermal curing conditions and with the increase of residue content, whose microstructure indicates the formation of more pores in the geopolymer matrix. The thermal curing promoted the formation of sodalite crystals, and the significant presence of Na particles on the surface suggests that part of the added NaOH did not react with the precursors.
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