Electric Conductivity Changes in Geopolymer Samples with Added Carbon Nanotubes

Kusák, Ivo; Lunak, Miroslav; Rovnanı́k, Pavel

doi:10.1016/j.proeng.2016.07.361

Cited by 26 publications

(7 citation statements)

References 6 publications

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“…Then calcite was added and mixed for 5 min. Finally, Na2SiO3 was added and mixed for 15 min and then the fresh cement was rapidly poured into a cubic steel mold of 40x40x40 mm 3 . In order to investigate the effect of the activator on the properties of the geopolymer material, a series of NaOH solution with concentrations of 5, 10, 15 and 20 M and Na2SiO3/NaOH weight ratio of 0.5, 1, 1.5 and 2 were used.…”

Section: Methodsmentioning

confidence: 99%

“…For geopolymerization process, raw materials do not need to be burned at high temperatures as in the case of Portland clinker while alkali active binders are being prepared. For that reason, geopolymers are environmentally friendly materials that do not release CO2 [3]. In addition, geopolymers are of great interested by researchers due to their superior mechanical strength, low shrinkage, acid resistance, fire resistance and low thermal conductivity [4].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Kaolinite Mass Ratio on Compressive Strength of Kaolinite-Calcite Based Geopolymer

Kütük¹,

Çetinkaya²

2017

International Journal of Computational and Experimental Science and Engineering

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This study focuses on the preparation of geopolymers using various proportions of kaolinite and calcite mixture, and the effects of kaolinite mass ratio to calcite on compressive strength of kaolinite/calcite-based geopolymer. Several geopolymer samples were formed using pure kaolinite, pure calcite, and various mass ratio of kaolinite to calcite to examine properties of the geopolymers. The impact of NaOH concentration on the compressive strength of the geopolymers was also examined. The results of the laboratory analyses indicate that the compressive strength of geopolymers did not increase steadily with increasing concentration of NaOH. The optimum workability of geopolymers was obtained at 10 M NaOH and 30 % kaolinite content in the mixture. Several sensitivity experiments were carried out using the parameters at cure temperatures of 22, 45, 65 and 85 o C. The best compressive strength of 12.68 MPa was obtained on the 28th day of curing process at 85 o C. The structural evolution of the geopolymers prepared was investigated using FTIR spectroscopy. They were also characterized by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM).

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Kaolinite Mass Ratio on Compressive Strength of Kaolinite-Calcite Based Geopolymer

Kütük¹,

Çetinkaya²

2017

International Journal of Computational and Experimental Science and Engineering

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“…Presently, the influence of CNT on geopolymers has been studied less because of mainly focusing on improving the mechanical and electrical properties of geopolymers. Kusak et al (2016) incorporated CNTs into a fine-abrasive blast furnace slag-based geopolymer and found that the absolute value of impedance decreased with an increase in the amount of CNTs. Moreover, the relative dielectric constant increased overall.…”

Section: Introductionmentioning

confidence: 99%

Hybrid Effect of PVA Fibre and Carbon Nanotube on the Mechanical Properties and Microstructure of Geopolymers

Meng

Yang

et al. 2021

Front. Mater.

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The concept of geopolymers has been widely studied since it was proposed. However, the wide range of applications of geopolymers is affected by brittleness and poor crack resistance. In this study, the mechanical properties of geopolymers with single-doped PVA fibres, single-doped carbon nanotubes, and mixed PVA fibers and carbon nanotubes were studied respectively first. It was found that PVA fibres and carbon nanotubes had a positive effect on improving the mechanical properties of geopolymers, especially bending strength and flexural strength. Moreover, the incorporation of PVA fibre could improve the damage morphology of geopolymers. Additionally, the phase analysis, structural group analysis, and strengthening mechanism were studied via scanning electron microscopy, mercury intrusion porosimetry analysis, X-ray diffraction pattern characterisation, Fourier transform infrared spectroscopy analysis, and magic angle spinning nuclear magnetic resonance analysis. It was found that the strengthening effect of PVA fiber to the geopolymer was primarily a physical strengthening effect, whereas the strengthening effect of carbon nanotubes to the geopolymers was both chemical and physical. Finally, based on the previous study, a multi-scale dual-fibre strengthening mechanism was proposed. Micro-nano fibre composites were used to improve microstructure via physical and chemical effects. This is helpful to improve the performance and application of geopolymers. Furthermore, it lays a preliminary theoretical foundation for engineering applications and technical improvement of geopolymers in the future.

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“…e geopolymers show attractive potentials and superior properties such as fire and chemical resistances, with no CO 2 emissions during their elaboration, thermal stability, electrical resistance, high strength, lower creep and shrinkage, elimination, decomposition, immobilization, and encapsulation of organic and inorganic pollutants [15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Influence of the Nature and Rate of Alkaline Activator on the Physicochemical Properties of Fly Ash-Based Geopolymers

Alouani

Alehyen

Achouri

et al. 2020

Advances in Civil Engineering

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The influence of alkali cations on mix design of geopolymers is essential for their mechanical, thermal, and electrical performance. This research investigated the influence of alkali cation type on microscale characteristics and mechanical, dielectric, and thermal properties of fly ash-based geopolymer matrices. The geopolymers were elaborated via class F fly ash from the thermal plant Jorf Lasfar, El Jadida (Morocco), and several alkaline solutions. Morphological, structural, mechanical, dielectric, and thermal characteristics of materials synthesized via fly ash with different proportions of KOH and NaOH aged 28 days were evaluated. The physicochemical properties of class F fly ash-based geopolymers were assessed using X-ray diffraction (XRD), Fourier-transform infrared spectrometry (FTIR), and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDX) analyses. Based on readings of the results obtained, XRD and FTIR analysis detected the creation of semicrystalline potassium/sodium aluminate-silicate hydrate (KASH/NASH) gel in the elaborated matrices after the geopolymerization reaction. The SEM analysis proved the formation of alkali alumina-silicate hydrate gel in the raw material particles after the polycondensation stage. Experimental compressive strength data indicated that the highest compressive strength (39 MPa) was produced by the alkaline activator (75% KOH/25% NaOH). The dielectric parameters values of the elaborated materials changed depending of the mass ratios KOH/NaOH. Dielectric findings demonstrated that geopolymers containing 100% NaOH have better dielectric performances. The fire resistance study revealed that the geopolymer binders induced by KOH are stable up to 600°C. Based on these results, it can be deduced that the formulated geopolymer concrete possesses good mechanical, dielectric, and fire resistance properties.

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Electric Conductivity Changes in Geopolymer Samples with Added Carbon Nanotubes

Cited by 26 publications

References 6 publications

Effect of Kaolinite Mass Ratio on Compressive Strength of Kaolinite-Calcite Based Geopolymer

Effect of Kaolinite Mass Ratio on Compressive Strength of Kaolinite-Calcite Based Geopolymer

Hybrid Effect of PVA Fibre and Carbon Nanotube on the Mechanical Properties and Microstructure of Geopolymers

Influence of the Nature and Rate of Alkaline Activator on the Physicochemical Properties of Fly Ash-Based Geopolymers

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