Development and characterization of sustainable lightweight geopolymer composites

Khater, H. M.

doi:10.1590/0366-69132019653732551

Cited by 12 publications

(8 citation statements)

References 20 publications

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“…In this case, the advantages of using these materials are their low density, high fatigue strength, and resistance to dynamic loads [ 18 , 19 ]. Material density can be reduced by using lightweight and porous aggregates [ 19 , 20 ]. Concrete, including the geopolymer one, is considered light when its dry density is within the range of 800–2000 kg/m 3 [ 20 , 21 ].…”

Section: Introductionmentioning

confidence: 99%

“…Material density can be reduced by using lightweight and porous aggregates [ 19 , 20 ]. Concrete, including the geopolymer one, is considered light when its dry density is within the range of 800–2000 kg/m 3 [ 20 , 21 ]. Examples of aggregates that can be used to obtain geopolymeric materials with relatively high strength and low density are microspheres [ 22 , 23 , 24 , 25 , 26 , 27 ], vermiculite [ 28 , 29 ], granulated foam glass [ 30 , 31 , 32 ], expanded polystyrene (Styrofoam) [ 29 , 33 ], pumice [ 34 , 35 ], perlite [ 36 , 37 , 38 ], and other expanded materials, e.g., clay or glass [ 39 , 40 , 41 ].…”

Section: Introductionmentioning

confidence: 99%

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Development and Characterization of Lightweight Geopolymer Composite Reinforced with Hybrid Carbon and Steel Fibers

et al. 2021

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The aim of this paper is to analyze the influence of hybrid fiber reinforcement on the properties of a lightweight fly ash-based geopolymer. The matrix includes the ratio of fly ash and microspheres at 1:1. Carbon and steel fibers have been chosen due to their high mechanical properties as reinforcement. Short steel fibers (SFs) and/or carbon fibers (CFs) were used as reinforcement in the following proportions: 2.0% wt. CFs, 1.5% wt. CFs and 0.5% wt. SFs, 1.0% wt. CFs and 1.0% wt. SFs, 0.5% wt. CFs and 1.5% wt. SFs and 2.0% wt. SFs. Hybrid reinforcement of geopolymer composites was used to obtain optimal strength properties, i.e., compressive strength due to steel fiber and bending strength due to carbon fibers. Additionally, reference samples consisting of the geopolymer matrix material itself. After the production of geopolymer composites, their density was examined, and the structure (using scanning electron microscopy) and mechanical properties (i.e., bending and compressive strength) in relation to the type and amount of reinforcement. In addition, to determine the thermal insulation properties of the geopolymer matrix, its thermal conductivity coefficient was determined. The results show that the addition of fiber improved compressive and bending strength. The best compressive strength is obtained for a steel fiber-reinforced composite (2.0% wt.). The best bending strength is obtained for the hybrid reinforced composite: 1.5% wt. CFs and 0.5% wt. SFs. The geopolymer composite is characterized by low thermal conductivity (0.18–0.22 W/m ∙ K) at low density (0.89–0.93 g/cm3).

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Development and Characterization of Lightweight Geopolymer Composite Reinforced with Hybrid Carbon and Steel Fibers

et al. 2021

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“…9 shows that the 4 polished samples exhibited dense morphology with homogeneous particle/resin dispersion, which can be explained by the higher presence of kaolinite in the D SA powder. This constituent reproduced a nucleation effect, similar to aluminum seeding [46], clearly illustrating the cohesion of the formed matrix. However, significant microstructural differences can be detected between Figs.…”

Section: Resultsmentioning

confidence: 53%

Artificial stone production using iron ore tailing (IOT)

Silva

Paiva

2020

Cerâmica

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Artificial stone materials (ASM) were produced with an iron ore tailing (IOT) from the disruption of Fundão’s tailing dam, located in Mariana, Minas Gerais State, Brazil. The IOT was separated in 3 powders with different particle sizes: DAG (<600 μm), DAR (600 to 75 μm), and DSA (<75 μm); then, each powder was characterized and mixed with a polymer resin (polyester or epoxy). ASM samples were prepared using the transfer molding technique; vacuum vibration technology was also applied to half of the samples. After curing, the ASM samples were characterized for mechanical properties and physical parameters. The microstructure of polished ASM samples was also analyzed by scanning electron microscopy. All results indicated that ASM samples produced with epoxy resin were superior to the samples made with polyester resin. The features found for the different compositions and shaping conditions for the produced ASM samples can allow various applications for these alternative materials in the construction industry, such as floor and wall tiles, providing a means of reducing the amount of IOT deposited in the tailing dams and adding economic value to this waste.

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“…There is a wide formation of secondary phases that can be set up depending on the chemical composition of the studied precursors, as highlighted by Figure 8. That is because several factors, such as alkalinity, water/binder ratio, curing environment (duration, humidity, and temperature), besides the relationship among the components, the main ones being Ca, Mg, Si, Al, and Na, they affect the phases and compounds formed in the alkali-activated relationship [68], [69]. It is worth noting that the secondary phases formed are rich in Al since, as highlighted in the previous paragraph, the excess of Al causes the precipitation of other phases out of the principal C-A-S-H gels [2], [8], [57].…”

Section: Alkali Activation Reaction Of Of Calcium-rich Precursorsmentioning

confidence: 99%

Reaction mechanisms of alkali-activated materials

Marvila

Azevedo

Vieira

2021

Rev. IBRACON Estrut. Mater.

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The Alkali-Activated Materials (AAM) are defined as materials obtained through the reaction between precursors and activators, and are separated into two classes depending on the products formed in the reaction, those rich in calcium, as the blast furnace slag, whose Ca/(Si+Al) ratio is higher than 1; and poor in calcium, which is the geopolymers subclass. In this review article, some bibliographical aspects were discussed regarding the discovery of these materials, through research conducted by Victor Glukhovsky and through the characterization of historical monuments by Davidovits, which began in the 50s and 60s and persist to the present day. The main products obtained in the alkaline activation reaction were also addressed, using the definition of polysialates and zeolites, in the case of geopolymers, and the tobermorite structure, in the case of materials rich in calcium. The main steps of the alkali-activated reaction, such as dissolution, condensation, polycondensation, crystallization, and hardening, were discussed. Some techniques for characterizing the AA reaction products were also examined, such as X-ray diffraction (XRD), nuclear magnetic resonance spectrometry (NMR), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Finally, the main factors that interfere in the kinetics of AA reactions were explored, in which the type of cure and the activating solution used in the alkali-activated materials production stands out.

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Development and characterization of sustainable lightweight geopolymer composites

Cited by 12 publications

References 20 publications

Development and Characterization of Lightweight Geopolymer Composite Reinforced with Hybrid Carbon and Steel Fibers

Development and Characterization of Lightweight Geopolymer Composite Reinforced with Hybrid Carbon and Steel Fibers

Artificial stone production using iron ore tailing (IOT)

Reaction mechanisms of alkali-activated materials

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