Combined Functionalization of Carbon Nanotubes (CNT) Fibers with H2SO4/HNO3 and Ca(OH)2 for Addition in Cementitious Matrix

Batiston, Eduardo Roberto; Matos, Paulo Ricardo de; Gleize, Philippe Jean Paul; Fediuk, Roman; Klyuev, Sergey; Vatin, Nikolai; Karelina, M. Yu.

doi:10.3390/fib9030014

Cited by 11 publications

(6 citation statements)

References 44 publications

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“…The I D /I G ratio of the carboxyl-functionalized CNT used in this study is higher than the I D /I G ratio of the non-functionalized CNT reported in previous studies. Batiston et al [18] used non-functionalized CNT with an I D /I G ratio of 0.89. The non-functionalized CNT evaluated by Bogas et al [19] showed an I D /I G ratio of 0.85.…”

Section: Methodsmentioning

confidence: 99%

Influence of Ultrasonication of Functionalized Carbon Nanotubes on the Rheology, Hydration, and Compressive Strength of Portland Cement Pastes

et al. 2021

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The functionalization process usually increases the localized defects of carbon nanotubes (CNT). Thus, the ultrasonication parameters used for dispersing non-functionalized CNT should be carefully evaluated to verify if they are adequate in dispersing functionalized CNT. Although ultrasonication is widely used for non-functionalized CNT, the effect of this dispersing process of functionalized CNT has not been thoroughly investigated. Thus, this work investigated the effect of ultrasonication on functionalized CNT + superplasticizer (SP) aqueous dispersions by ultraviolet-visible (UV-Vis) spectroscopy, dynamic light scattering (DLS), and Fourier transform infrared spectroscopy (FTIR). Furthermore, Portland cement pastes with additions of 0.05% and 0.1% CNT by cement weight and ultrasonication amplitudes of 0%, 50% and 80% were evaluated through rheometry, isothermal calorimetry, compressive strength at 1, 7 and 28 days, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). FTIR results from CNT + SP dispersions indicated that ultrasonication may negatively affect SP molecules and CNT graphene structure. The increase in CNT content and amplitude of ultrasonication gradually increased the static and dynamic yield stress of paste but did not significantly affect its hydration kinetics. Compressive strength results indicated that the optimum CNT content was 0.05% by cement weight, which increased the strength of composite by up to 15.8% compared with the plain paste. CNT ultrasonication neither increases the degree of hydration of cement nor the mechanical performance of composite when compared with mixes containing unsonicated CNT. Overall, ultrasonication of functionalized CNT is not efficient in improving the fresh and hardened performance of cementitious composites.

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Section: Methodsmentioning

confidence: 99%

Influence of Ultrasonication of Functionalized Carbon Nanotubes on the Rheology, Hydration, and Compressive Strength of Portland Cement Pastes

et al. 2021

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“…The increasing complexity of the vehicle design contributes to an increase in costs, both for spare parts and for maintenance and repair complexes, as well as for operating materials. However, these changes are also made possible to consider when building a multi-criteria model based on the data given, for example, in [19][20][21][22] on the specifics of innovative building and machine-building materials.…”

Section: Methodsmentioning

confidence: 99%

Methods of systemic management of the service life of vehicles

et al. 2021

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The article discusses the methods of multi-criteria assessment of the efficiency of vehicle operation according to their properties. The main difficulties in solving the issue of technical operation of vehicles when introducing these methods into the assessment process are highlighted. Algorithms of decision-making related to the choice of a vehicle in conditions of uncertainty of the external environment are analyzed. Their advantages and disadvantages are substantiated. A methodology for calculating weight coefficients for the optimization and development of the transport system is proposed.

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“…The heat release of concrete Q was determined according to EN 196-9: 2010 [35], by the semi-adiabatic (thermos) method at an initial concrete temperature of 20 • C, and by calculation was reduced to an isothermal hardening regime at a temperature of 20 • C using the reduced time hypothesis [1], according to which at moments of equal heat release at Q 1 = Q 2 , the ratio of the heat release rates, as well as the corresponding times τ 2 and τ 1 , remains constant throughout the entire process:…”

Section: Concrete Testingmentioning

confidence: 99%

“…Much attention is paid to a direction in concrete technology associated with using nanostructures of carbon, oxides of silicon, titanium, iron, and others [1][2][3][4][5]. Among the modifying additives, the use of microfibrillar cellulose in cement composites is being actively studied.…”

Section: Introductionmentioning

confidence: 99%

Influence of Microfibrillated Cellulose Additive on Strength, Elastic Modulus, Heat Release, and Shrinkage of Mortar and Concrete

2021

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This work aimed to study the effect of a microfibrillated cellulose additive on strength, elastic modulus, heat release, and shrinkage of mortar and concrete. The dosage of the additive varies from 0.4 to 4.5% by weight of the cement. The change in strength with an increase in the dosage of the additive occurred in a wave-like manner. The uneven character of the change in the results also took place in the determination of heat release and shrinkage. In general, heat release and shrinkage decreased at increasing additive dosage. The additive showed the greatest decrease in the heat release of concrete at a content of 2%. The heat release of concrete practically differed little from the exotherm of the standard at an additive content of 1 and 1.5%. The addition of microfibrillated cellulose additive in small (0.5%) and large (1.5%) amounts reduced shrinkage compared to the reference, and at an intermediate content (1%), the shrinkage was higher than in the reference specimens. In this case, the water evaporation rate from concrete increased with an increase in the additive. With an increase in the additive dosage, the modulus of elasticity decreases. Thus, the microfibrillated cellulose additive provides concrete with lower values of the modulus of elasticity, heat release, and shrinkage, and the additive is recommended for use in concretes with increased crack resistance during the hardening period. The recommended additive content is 0.5% by weight of cement. At the specified dosage, it is possible to provide the class of concrete in terms of compressive strength C35/45.

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Combined Functionalization of Carbon Nanotubes (CNT) Fibers with H2SO4/HNO3 and Ca(OH)2 for Addition in Cementitious Matrix

Cited by 11 publications

References 44 publications

Influence of Ultrasonication of Functionalized Carbon Nanotubes on the Rheology, Hydration, and Compressive Strength of Portland Cement Pastes

Influence of Ultrasonication of Functionalized Carbon Nanotubes on the Rheology, Hydration, and Compressive Strength of Portland Cement Pastes

Methods of systemic management of the service life of vehicles

Influence of Microfibrillated Cellulose Additive on Strength, Elastic Modulus, Heat Release, and Shrinkage of Mortar and Concrete

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