Glass waste versus sand as aggregates: The characteristics of the evolving geopolymer binders

Hajimohammadi, Ailar; Ngo, Tuan; Kashani, Alireza

doi:10.1016/j.jclepro.2018.05.086

Cited by 119 publications

(62 citation statements)

References 49 publications

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“…Crack deflection as a reinforcement mechanism was found also for SC-WG samples ( Figure S5 ), while for the HC-NF sample the loose structure was efficiently densified only by MK addition ( Figure S6 ). Additionally, the effect of very fine WG particles is to produce a denser matrix, as reported in the literature for fly-ash based mixes [ 27 ].…”

Section: Resultsmentioning

confidence: 99%

Effect of the Introduction of Reactive Fillers and Metakaolin in Waste Clay-Based Materials for Geopolymerization Processes

Sgarlata

Formia²,

Ferrari³

et al. 2021

Molecules

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In this study, the role of two reactive fillers, specifically a sand from a clay washing process as an alternative to waste glass powder and a commercial metakaolin (MK), into the geopolymerization process of waste clay-based materials was assessed. Three kinds of clayey wastes from mining operations—halloysitic, kaolinitic and smectitic clays—were tested as potential precursor of geopolymeric materials in view of a potential valorisation of these by-products. A mix-design based on the addition of low percentages (20%) of these fillers or MK to improve the mechanical and chemico-physical properties of geopolymeric formulations was evaluated. All the clays were thermally treated at a temperature of 650 °C, while the geopolymeric pastes were cured at room temperature. In particular, the chemical stability in water (pH and ionic conductivity of leachate water, weight loss), the variations in the microstructure (XRD, SEM), and in the mechanical performance (compressive strength) were analysed. The most reactive additive was MK, followed by sand and waste glass at very similar levels—1:1 or 2:1—depending upon the type of the clay but not strictly related to the clay type. The increase of geopolymeric gel densification due to the presence of MK and sand was replaced by a crack deflection mechanism in the case of the WG grains. The worst performance (chemical stability and mechanical properties) was found for the halloysitic clay, while kaolinitic and smectitic clays developed strengths slightly below 30 MPa.

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Section: Resultsmentioning

confidence: 99%

Effect of the Introduction of Reactive Fillers and Metakaolin in Waste Clay-Based Materials for Geopolymerization Processes

Sgarlata

Formia²,

Ferrari³

et al. 2021

Molecules

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“…In an alkali-activated fly ash/slag (AAFS) blended system, the main reaction product is a coexistence of N-A-S-H gel and C-A-S-H [4]. AAMs can not only provide comparable performance to OPC [5] but also reduce CO 2 emissions [6] and solid wastes [7,8]. Moreover, AAMs have advantages of rapid setting and hardening [9], high compressive strength [10][11][12], high durability [13,14], low thermal conductivity, high fire resistance [15], resistance to alkali aggregate reaction [16], and high freeze-thaw resistance [17].…”

Section: Introductionmentioning

confidence: 99%

Effect of the Sodium Silicate Modulus and Slag Content on Fresh and Hardened Properties of Alkali-Activated Fly Ash/Slag

Ouyang

Liu

et al. 2019

Minerals

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This paper presents the results of an experimental study performed to investigate the effect of activator modulus (SiO2/Na2O) and slag addition on the fresh and hardened properties of alkali-activated fly ash/slag (AAFS) pastes. Four activator moduli (SiO2/Na2O), i.e., 0.0, 1.0, 1.5, and 2.0, and five slag-to-binder ratios, i.e., 0, 0.3, 0.5, 0.7, 1.0, were used to prepare AAFS mixtures. The setting time, flowability, heat evolution, compressive strength, microstructure, and reaction products of AAFS pastes were studied. The results showed that the activator modulus and slag content had a combined effect on the setting behavior and workability of AAFS mixtures. Both the activator modulus and slag content affected the types of reaction products formed in AAFS. The coexistence of N–A–S–H gel and C–A–S–H gel was identified in AAFS activated with high pH but low SiO2 content (low modulus). C–A–S–H gel had a higher space-filling ability than N–A–S–H gel. Thus, AAFS with higher slag content had a finer pore structure and higher heat release (degree of reaction), corresponding to a higher compressive strength. The dissolution of slag was more pronounced when NaOH (modulus of 0.0) was applied as the activator. The use of Na2SiO3 as activator significantly refined the pores in AAFS by incorporating soluble Si in the activator, while further increasing the modulus from 1.5 to 2.0 prohibited the reaction process of AAFS, resulting in a lower heat release, coarser pore structure, and reduced compressive strength. Therefore, in view of the strength and microstructure, the optimum modulus is 1.5.

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“…Diferentes estudos já avaliaram a aplicação desses resíduos como substituintes, tanto dos agregados miúdos e graúdos quanto de parcela do cimento. Como exemplo, podem-se citar resíduos de areia de fundição [4][5][6][7][8], resíduos de vidro e pó de vidro [9][10][11][12], resíduos da própria construção civil [13][14][15][16], resíduos cerâmicos [1, [17][18][19] e, também, resíduos agroindustriais [3, [20][21][22][23][24], dentre inúmeros outros.…”

Section: Introductionunclassified

Aplicação de resíduos na fabricação de concreto: como técnicas analíticas de caracterização podem auxiliar na escolha preliminar do material mais adequado?

Bragagnolo

Korf

2020

Matéria (Rio J.)

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RESUMO A preocupação frente aos impactos negativos resultantes da obtenção e produção de agregados naturais e do cimento na produção do concreto, bem como a possibilidade de escassez desses, acabaram alavancando a busca por materiais alternativos. Dentre esses materiais, diversos estudos já avaliaram a aplicação de subprodutos de diferentes setores industriais para a fabricação do concreto. Contudo, considerando a gama de resíduos existentes, sem ainda possuir algum valor agregado, torna-se interessante avaliá-los para essa finalidade. Para tanto, a avaliação do potencial desses materiais exige a aplicação de diferentes técnicas para análise de diversas propriedades que são desejáveis ou requeridas. Nesse sentido, essa revisão bibliográfica buscou reunir as principais técnicas e metodologias que são aplicadas para a identificação das principais características que possibilitem sua aplicação como substitutos parciais de agregados ou cimento, em misturas para a fabricação do concreto.

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Glass waste versus sand as aggregates: The characteristics of the evolving geopolymer binders

Cited by 119 publications

References 49 publications

Effect of the Introduction of Reactive Fillers and Metakaolin in Waste Clay-Based Materials for Geopolymerization Processes

Effect of the Introduction of Reactive Fillers and Metakaolin in Waste Clay-Based Materials for Geopolymerization Processes

Effect of the Sodium Silicate Modulus and Slag Content on Fresh and Hardened Properties of Alkali-Activated Fly Ash/Slag

Aplicação de resíduos na fabricação de concreto: como técnicas analíticas de caracterização podem auxiliar na escolha preliminar do material mais adequado?

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