Analysis of Cementitious Composites Prepared with Carbon Nanotubes and Nanofibers Synthesized Directly on Clinker and Silica Fume

Ludvig, Péter; Calixto, José Márcio Fonseca; Ladeira, Luiz Orlando; Souza, Tarcizo da Cruz C. de; Paula, Júnia Nunes de

doi:10.1061/(asce)mt.1943-5533.0001836

Cited by 9 publications

(5 citation statements)

References 10 publications

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Section: Resultsmentioning

confidence: 99%

“…The isotherm curves of these three cement pastes are similar. According to the International Union of Pure and Applied Chemistry (IUPAC), the classification of the three isotherms presented in Figure 10 is isotherm type II and hysteresis type H3, which indicate slit shape pores, characteristics of C-S-H [32]. According to Figure 10, a higher hysteresis in the presence of CNTs is observed; the desorption curve is more distant from the adsorption for 0.05-ISO and 0.10-ISO, than for the REF-ISO paste.…”

Section: Evaluation Of the Physical Parametersmentioning

confidence: 99%

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Influence of Carbon Nanotubes on the Mechanical Behavior and Porosity of Cement Pastes Prepared by A Dispersion on Cement Particles in Isopropanol Suspension

Rocha

Ludvig

2020

Materials

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Cement composites prepared with nanoparticles have been widely studied in order to achieve superior performance structures. The incorporation of carbon nanotubes (CNTs) is an excellent alternative due to their mechanical, electrical, and thermal properties. However, effective dispersion is essential to ensure strength gains. In the present work, cement pastes were prepared incorporating CNTs in proportions up to 0.10% by weight of cement, dispersed on the surface of anhydrous cement particles in isopropanol suspension and using ultrasonic agitation. Digital image correlation was employed to obtain basic mechanical parameters of three-point bending tests. The results indicated a 34% gain in compressive strength and 12% in flexural tensile strength gains, respectively, as well as a 70% gain in fracture energy and 14% in fracture toughness in the presence of 0.05% CNTs were recorded. These results suggest that CNTs act as crack propagation controllers. Moreover, CNT presence contributes to pore volume reduction, increases the density of cement pastes, and suggests that CNTs additionally act as nucleation sites of the cement hydration products. Scanning electron microscopy images indicate effective dispersion as a result of the methodology adopted, plus strong bonding between CNTs and the cement hydration product. Therefore, CNTs can be used to obtain more resistant and durable cement-based composites.

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Section: Resultsmentioning

confidence: 99%

Section: Evaluation Of the Physical Parametersmentioning

confidence: 99%

Influence of Carbon Nanotubes on the Mechanical Behavior and Porosity of Cement Pastes Prepared by A Dispersion on Cement Particles in Isopropanol Suspension

Rocha

Ludvig

2020

Materials

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“…The in-situ synthesis on clinker produces lower quality nanotubes, but can be easily upgraded to industrial scale. The addition of this nanostructured clinker resulted in similar effects on the rheology of fresh paste [4], on the mechanical behaviour [8], and on the microstructure [9] as the addition of high quality CNTs.…”

Section: S T R E S Z C Z E N I Ementioning

confidence: 89%

Nanocomposites Prepared by a Dispersion of CNTS on Cement Particles

Rocha

Ludvig

2018

Architecture, Civil Engineering, Environment

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Carbon nanotubes (CNTs) are hollow tubular channels, formed by graphene laminated sheets. They can be classified as single-walled (SWCNTs) when they have a simple cylindrical layer of graphene or as multiple-walled (MWCNTs) formed by the joining of two or more single cylindrical layers. Due to the extraordinary properties, as a high tensile strength, the incorporation of the CNTs in civil construction materials has been studied. Recent research has shown that the incorporation of this nanomaterial allows improvements in the mechanical properties of cementitious compounds [1-5]. However, the hydrophobic nature of CNTs makes the dispersion a

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“…This process, patented by Ladeira et al [12], promotes a natural dispersion of CNTs making their application in the context of the construction industry more adequate. Investigations, that use this technology, show significative results in terms of gains in compressive and tensile strength [13,14,15]. In continuation of previous studies [13,14,15], the goal of this work is to present the results of the fresh state rheological behavior as well as of the initial hydration period of blast furnace slag (Brazilian CP III 40 RS) Portland cement pastes produced with carbon nanotubes grown directly on clinker.…”

Section: Introductionmentioning

confidence: 92%

“…Investigations, that use this technology, show significative results in terms of gains in compressive and tensile strength [13,14,15]. In continuation of previous studies [13,14,15], the goal of this work is to present the results of the fresh state rheological behavior as well as of the initial hydration period of blast furnace slag (Brazilian CP III 40 RS) Portland cement pastes produced with carbon nanotubes grown directly on clinker. The yield stress, plastic viscosity, temperature profile and evolved accumulated heat during the initial hydration period as well as setting times are the properties investigated.…”

Section: Introductionmentioning

confidence: 92%

Early-age behavior of blast-furnace slag cement pastes produced with carbon nanotubes grown directly on clinker

Soares

Benedetti

Souza

et al. 2020

Rev. IBRACON Estrut. Mater.

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Carbon nanotubes are a promising material to solve the low tensile strength and ductility of Portland cement-based materials. Carbon nanotubes (CNTs) synthesized directly on cement clinker particles can also reduce production costs and help dispersion. In this scenario, this paper analyzes the fresh state rheological behavior, as well as the initial hydration period of blast-furnace slag (Brazilian CP III 40 RS) cement pastes produced with CNTs grown directly on clinker. CP III 40 RS was selected since it is one of the most used cement by the construction industry in Brazil. Cement pastes containing 0.1% and 0.3% of CNTs with respect to cement content were compared with CNT-free pastes. No chemical admixtures were used as a dispersant in all cases. The yield stress, plastic viscosity, temperature profile and evolved accumulated heat during the initial hydration period as well as setting times are the properties investigated. The results show that the addition of CNTs does not alter the rheological behavior of the cement pastes considering the employed concentrations, although the yield stress values were larger. The presence of CNTs in the cement pastes did not change the evolved accumulated heat during the first 72 hours of the hydration period.

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Analysis of Cementitious Composites Prepared with Carbon Nanotubes and Nanofibers Synthesized Directly on Clinker and Silica Fume

Cited by 9 publications

References 10 publications

Influence of Carbon Nanotubes on the Mechanical Behavior and Porosity of Cement Pastes Prepared by A Dispersion on Cement Particles in Isopropanol Suspension

Influence of Carbon Nanotubes on the Mechanical Behavior and Porosity of Cement Pastes Prepared by A Dispersion on Cement Particles in Isopropanol Suspension

Nanocomposites Prepared by a Dispersion of CNTS on Cement Particles

Early-age behavior of blast-furnace slag cement pastes produced with carbon nanotubes grown directly on clinker

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