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

Silvestro, Laura; Ruviaro, Artur Spat; Lima, Geannina Terezinha dos Santos; Matos, Paulo Ricardo de; Azevedo, Afonso Rangel Garcez de; Monteiro, Sérgio Neves; Gleize, Philippe Jean Paul

doi:10.3390/ma14185248

Cited by 29 publications

(13 citation statements)

References 74 publications

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“…Similar trends of increasing the yield stress and viscosity of cement paste with other nanomaterials incorporation besides TiO 2 were previously reported by the authors [ 75 , 76 ] and by other research groups [ 77 , 78 , 79 ]. Specifically for 3DP mixes, Sikora et al [ 24 ] observed that 2% nano-SiO 2 incorporation was enough to increase the yield stress of 3DP mortars by 4.2 times (from 46 to 239 Pa).…”

Section: Resultssupporting

confidence: 89%

Effect of TiO2 Nanoparticles on the Fresh Performance of 3D-Printed Cementitious Materials

et al. 2022

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3D printing (3DP) of cementitious materials shows several advantages compared to conventional construction methods, but it requires specific fresh-state properties. Nanomaterials have been used in cement-based materials to achieve specific fresh and hardened properties, being potential candidates for 3DP applications. However, there are no reports on using TiO2 nanoparticles (nano-TiO2) in 3DP cementitious composites. Thus, the current work aims to assess the effect of nano-TiO2 on the fresh performance of 3DP cementitious materials. For this purpose, nano-TiO2 was incorporated in pastes and mortars from 0 to 1.5 wt.%. Time-resolved hydration (in situ XRD) and rheological and printing-related properties (buildability and printability) were evaluated. Results showed that nano-TiO2 particles enhanced the cement hydration kinetics, leading to further ettringite formation up to 140 min compared to plain cement paste. Rheological measurements showed that the nano-TiO2 incorporation progressively increased the static and dynamic stress, viscosity, and structuration rate of pastes. Furthermore, nano-TiO2 improved the buildability of the composites, progressively increasing the maximum number of successive layers printed before failure from 11 (0 wt.% TiO2) to 64 (1.5 wt.% TiO2). By contrast, the nano-TiO2 addition reduced the printability (i.e., the printable period during which the sample was able to be molded by the 3D-printing process) from 140 min (0% TiO2) to 90 min (1.5% TiO2). Thus, incorporating “high” nano-TiO2 contents (e.g., >1 wt.%) was beneficial for buildability but would require a quicker 3DP process. The adoption of nano-TiO2 contents of around 0.75–1.00% may be an interesting choice since it reduced the printability of paste by 30 min compared with the control mix but allowed for printing 24 layers (118% higher than plain mortar).

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Section: Resultssupporting

confidence: 89%

Effect of TiO2 Nanoparticles on the Fresh Performance of 3D-Printed Cementitious Materials

et al. 2022

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“…Moreover, a superplasticizer was also employed (MC-PowerFlow, Mc-Bauchemie). A complete characterization of all the materials used in this research can be obtained in previous studies published by the authors [12,[19][20][21]. For the simulated cement pore solution, calcium sulfate dihy-…”

Section: Methodsmentioning

confidence: 99%

“…Although CNTs functionalized with polar groups are more hydrophilic and, therefore, have a better dispersion in water, the dispersion in the cement matrix differs in the presence of a highly alkaline environment [12]. For instance, Zou et al [13] observed different optimal ultrasonication values for CNT dispersion in water (determined by UV-visible spectroscopy) and in a cementitious matrix considering the mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

“…of all the materials used in this research can be obtained in previous studies published by the authors[12,[19][20][21]. For the simulated cement pore solution, calcium sulfate dihydrate (≥99.0%, Neon, São Paulo, Brazil), potassium hydroxide (≥85.0%, Laffan, São Paulo, Brazil), sodium hydroxide (≥98.0%, Sigma-Aldrich, St. Louis, MO, USA), and calcium hydroxide (≥95.0%, Nuclear, São Paulo, Brazil) were used.…”

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Stability of Carboxyl-Functionalized Carbon Nanotubes in Simulated Cement Pore Solution and Its Effect on the Compressive Strength and Porosity of Cement-Based Nanocomposites

Silvestro

Lima

Ruviaro

et al. 2022

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The application of carbon nanotubes to produce cementitious composites has been extensively researched. However, the dispersion of this nanomaterial remains a technical limitation for its use. Thus, initially, this study assessed the stability of carboxyl-functionalized CNT on aqueous suspensions and simulated cement pore solution for 6 h through UV–visible spectroscopy. Subsequently, a CNT content of 0.1% by cement weight was incorporated into the cement pastes, and the compressive strength after 7, 14, 28, and 91 days was evaluated. In addition, the porosity of the CNT cementitious composites at 28 days of hydration was investigated by mercury intrusion porosimetry (MIP), and the microstructure was evaluated via scanning electron microscopy (SEM). The simulated cement pore solution’s alkaline environment affects the CNT stability, progressively reducing the dispersed CNT concentration over time. CNT reduced the cementitious matrix pores < 50 nm by 8.5%; however, it resulted in an increase of 4.5% in pores > 50 nm. Thus, CNT incorporation did not significantly affect the compressive strength of cement pastes. SEM results also suggested a high porosity of CNT cementitious composites. The CNT agglomeration trend in an alkaline environment affected the CNT performance in cement-based nanocomposites.

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“…Nevertheless, uniform dispersion of the fibers throughout the cementitious matrix is of particularly great significance [6,16,17]. The congregation and nonuniform distribution of fibers in the matrix can compromise the consolidation, mechanical strength, and ductility of UHPC [18,19].…”

Section: Introductionmentioning

confidence: 99%

Effect of Polymers on Behavior of Ultra-High-Strength Concrete

et al. 2022

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The development of ultra-high-performance concrete (UHPC) is still practically limited due to the scarcity of robust mixture designs and sustainable sources of local constituent materials. This study investigates the engineering characteristics of Styrene Butadiene Rubber (SBR) polymeric fiber-reinforced UHPC with partial substitution of cement at 0, 5 and 20 wt.% with latex polymer under steam and air curing techniques. The compressive and tensile strengths along with capillary water absorption and sulfate resistance were measured to evaluate the mechanical and durability properties. Scanning Electron Microscopy (SEM) was carried out to explore the microstructure development and hydration products in the designed mixtures under different curing regimes. The results indicated that the mixtures incorporating 20 wt.% SBR polymer achieved superior compressive strength at later ages. Additionally, the tensile strength of the polymeric UHPC without steel fibers and with 20% polymers was enhanced by 50%, which promotes the development of novel UHPC mixtures in which steel fibers could be partially replaced by polymer, while enhancing the tensile properties.

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

Cited by 29 publications

References 74 publications

Effect of TiO2 Nanoparticles on the Fresh Performance of 3D-Printed Cementitious Materials

Effect of TiO2 Nanoparticles on the Fresh Performance of 3D-Printed Cementitious Materials

Stability of Carboxyl-Functionalized Carbon Nanotubes in Simulated Cement Pore Solution and Its Effect on the Compressive Strength and Porosity of Cement-Based Nanocomposites

Effect of Polymers on Behavior of Ultra-High-Strength Concrete

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