Produção de geopolímeros à base de cinza volante usando soluções ativadoras com diferentes composições de Na2O e Na2SiO3

Azevedo, A. G. de S.; Strecker, Kurt; Jr., A. G. de Araújo; Silva, C. A. da

doi:10.1590/0366-69132017633662078

Cited by 10 publications

(6 citation statements)

References 14 publications

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“…The concentration of the alkaline solution, temperature and curing time and the particle size and composition of the fly-ash are parameters that must be controlled in order to produce high strength inorganic binders 1,2,[19][20][21] . The composition of the fly-ash depends on the initial composition of the coal used to produce energy in the thermal power plant as well as the type of the incinerator and collection filter used in each thermoelectric power plant 22 .…”

Section: Introductionmentioning

confidence: 99%

Effect of Curing Temperature, Activator Solution Composition and Particle Size in Brazilian Fly-Ash Based Geopolymer Production

et al. 2019

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The geopolymer binder is a relatively new class of inorganic binding material of elevated mechanical strength and good chemical properties. This can be produced using clay minerals or byproducts of the industrial processes, such as metakaolin, fly-ash and blast furnace slag. In this work, geopolymers were produced by alkaline activation of a Brazilian fly-ash with simple and compound solutions (NaOH and NaOH + Na 2 SiO 3). The hardened specimens presented values of the mechanical strength close to 48 MPa when the activator used presented SiO 2 /Na 2 O ration close to 1.0 after 24 h of curing at 65 °C. The increase of the temperature to 90 °C favored the reactions of the N-AS -H gel (geopolymer) formation and compression strength increased to values close to 90 MPa after 24 h. It has been found that physical properties, such as density and porosity, varied when different SiO 2 /Na 2 O rations was present in alkaline solutions. Time, temperature of curing and particle size of fly-ash modified the mechanical and physical proprieties of hardened inorganic binder. Was observed the diffraction phases related to zeolitic phases and carbonate new bands of absorption were related to reactions of Na2O in excess with atmospheric CO 2. The variation of SiO 2 /Na 2 O modified the microstructural of the hardened specimens.

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Section: Introductionmentioning

confidence: 99%

Effect of Curing Temperature, Activator Solution Composition and Particle Size in Brazilian Fly-Ash Based Geopolymer Production

et al. 2019

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“…(C) granulometria a laser da cinza volante e do metacaulim e (D) difratograma de raios X dos materiais revelando maior frequência de materiais cristalinos na cinza volante. no espectro de absorção próximos a 3400 cm -1 e 1650 cm -1 indicam o alongamento e flexão, respectivamente, das moléculas de água (grupo H-O) (CHINDAPRASIRT et al, 2016;LEE et al,2002;AZEVEDO et al, 2017;S. OLEJNIK et al, 1968).…”

Section: Resultsunclassified

Ligante Ativado Por Álcali À Base De Cinza Volante E Metacaulim Flint Como Material De Reparo Para Estruturas De Concreto Armado

Ribeiro¹,

Campos²,

Brito³

et al. 2020

≫Congresso Brasileiro De Patologia Das Construções

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A exposição intensa das estruturas de concreto a situações inadequadas e ausência de manutenção podem conduzir a perigos potenciais, fazendo-se necessário ações de reforços e reparos para garantir a segurança e a durabilidade. No entanto, o impacto das soluções atualmente empregadas resulta na busca por opções mais sustentáveis. Este artigo relata a caracterização de um material álcali ativado à base de cinza volante e metacaulim Flint, a fim de inferir o seu potencial uso no reparo de estruturas de concreto. O estudo das propriedades reológicas e mecânicas sugerem que o ligante álcali ativado de cinza volante e metacaulim possui tempo de pega e resitências mecânicas adequadas para a aplicação em reparos rápidos em estruturas de concreto, sendo uma opção para os atuais materiais de reparo, além de representar uma solução socioeconômica e sustentável para os efeitos da cadeia de uma energia mais limpa e de custos adicionais na exploração mineral.

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“…The FA samples were characterized using a Shimadzu Energy Dispersive X-Ray Fluorescence, model EDX 8000 to determine the chemical composition. The particle size distribution of the fly ashes was measured by laser diffraction analysis, Malvern Mastersizer 2000 (0.02 -2000 μm), and the specific mass of the fly ashes was obtained with a Helium pycnometer, Micromeritics, model AccuPyc 1340 [17]. The morphology of the FA and the geopolymer samples were analyzed using scanning electron microscopy, Hitachi, model TM 300 with coupled EDS, Bruker, model X-Flash.…”

Section: Characterization Of Precursor Materials and The Geopolymer Pastesmentioning

confidence: 99%

“…The specific mass of the two FA samples is also presented in Table 1. [17], that the authors studied the production of fly ash-based alkali-activated materials with simple and compound solutions of NaOH and Na 2 SiO 3 . Other chemical elements are also present in lower concentrations.…”

Section: Characterization Of Fly Ash Samplesmentioning

confidence: 99%

“…The molar ratio SiO 2 /Al 2 O 3 is higher for fly ash A, 3.52, compared to 3.34 of fly ash B. A high SiO 2 /Al 2 O 3 molar ratio is desirable to promote more Si released during the dissolution process of the raw material and consequently a larger amount of N-A-S-H gel formed (AAM) [17]. Figure 2 shows SEM images of particles of FA-A and FA-B used in the production of the alkali-activated materials.…”

Section: Characterization Of Fly Ash Samplesmentioning

confidence: 99%

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Evaluation of different fly ash samples on the production of alkali-activated materials

Azevedo

Domingos

Strecker

2021

Rev. IBRACON Estrut. Mater.

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In this work, different samples of fly ash (FA-A and FA-B) classified as type F as used to produce the AAM samples. The FA-A presented a higher Fe2O3 content than FA-B, 6.1 to 3.8 wt.%, and a slightly higher SiO2/Al2O3 ratio of 3.52 in comparison to 3.34 of FA-B. The average particle size (D50) of fly ash A was 19.7 µm and of fly ash B 30.8 µm, while the specific mass of the ashes A and B were 2.38 and 2.21 g/cm3, respectively. The results revealed that the mechanical strength of the AAM produced with fly ash A was higher than fly ash B, close to 80 and 44 MPa, respectively. The variation of the strength has been attributed to the different SiO2/Al2O3 ratios and different particle sizes. The mechanical strength decreased with increasing curing time, which is attributed to excess alkali in the system. Only very small differences in porosity and density have been found.

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Produção de geopolímeros à base de cinza volante usando soluções ativadoras com diferentes composições de Na2O e Na2SiO3

Cited by 10 publications

References 14 publications

Effect of Curing Temperature, Activator Solution Composition and Particle Size in Brazilian Fly-Ash Based Geopolymer Production

Effect of Curing Temperature, Activator Solution Composition and Particle Size in Brazilian Fly-Ash Based Geopolymer Production

Ligante Ativado Por Álcali À Base De Cinza Volante E Metacaulim Flint Como Material De Reparo Para Estruturas De Concreto Armado

Evaluation of different fly ash samples on the production of alkali-activated materials

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