Influence of MWCNT/surfactant dispersions on the mechanical properties of Portland cement pastes

Rodriguez, Brian J.; Quintero, Jorge; Arias, Yhan Paul; Reales, Oscar Aurelio Mendoza; Botero, Juan Carlos Ochoa; Toledo-Filho, R. D.

doi:10.1088/1742-6596/935/1/012014

Cited by 4 publications

(7 citation statements)

References 12 publications

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“…Moreover, nanotubes give additional strain capacity to the matrix by dissipating energy through multiple pulls out of nanotubes from the matrix before reaching a critical state (Figure 8). Rodríguez et al (2017) reported similar results regarding the bridging effect of CNTs. Therefore, the ability of [PM+SNF+MWCNTs] samples to maintain their integrity after the crack initiation suggests an interplay between the MWCNTs and the hydrated products mediated by a strong bond (Figure 9).…”

Section: Evolution Of the Applied Load Over Timesupporting

confidence: 61%

Mechanical and electrical properties of MWCNTs - high early strength cement - mortars composite: Dispersion of CNTs and effect of chemical admixtures

García

Márquez

Zúñiga-Suárez

et al. 2021

An. Acad. Bras. Ciênc.

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The objectives of this research were to study (1) the dispersion of MWCNTs in an aqueous system by three commercial admixtures (CAds) for concrete, and (2) the effect of CAds and MWCNTs on indirect tensile strength and electrical conductivity of MWCNTs-high early strength (HE) cement-mortar composites. To achieve the objectives, we dispersed MWCNTs in an aqueous system with (1) hydroxylated polymers-based water reducing plasticizer (HPs), a nonionic compound, (2) Naphthalene based superplasticizer (SNF), an anionic compound, and (3) calcium chloride-based accelerating agent (CC) a neutral amphoteric salt. We prepared a total of 242 samples grouped in three sets: (1) Plain mortar [PM] (water + HE cement + Sand), (2) [PM+CAd], and (3) [PM+CAd+MWCNTs]. The three CAds dispersed MWCNTs in an aqueous solution. The CC and HPs admixtures have a two-time bigger dispersing power than the SNF. They demand half of SNF's ultrasound energy for optimal dispersion. Although the SNF (anionic) based superplasticizer resulted incompatible with the HE cement, it improved the indirect tensile strength of [PM+SNF+MWCNTs] composite. In contrast, the CC (amphoteric) based accelerating agent was compatible with the HE cement; the CC adsorption on the MWCNTs surface favors an improvement in the electrical conductivity of [PM+CAd+MWCNTs] composite.

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Section: Evolution Of the Applied Load Over Timesupporting

confidence: 61%

Mechanical and electrical properties of MWCNTs - high early strength cement - mortars composite: Dispersion of CNTs and effect of chemical admixtures

García

Márquez

Zúñiga-Suárez

et al. 2021

An. Acad. Bras. Ciênc.

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“…As a result, air is entrapped in the cementitious matrix. According to the literature, this leads to a material with lower bulk density, increased porosity, and poor mechanical performance [ 34 , 35 , 36 , 37 , 38 , 39 ]. The results indicate that the exploitation of these two surfactants (SDBS and Triton X-100) to disperse MWCNTs in white cement mortars should be avoided as it has been proven that they are not compatible with the cementitious matrix.…”

Section: Resultsmentioning

confidence: 99%

Dispersion of Multi-Walled Carbon Nanotubes into White Cement Mortars: The Effect of Concentration and Surfactants

et al. 2022

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Multi-wall carbon nanotubes (MWCNTs) exhibit exceptional mechanical and electrical properties and can be used to improve the mechanical and piezoelectric properties of cement-based materials. In the present study, the effect of different MWCNT concentrations as well as different types of surfactants and a superplasticizer were examined to reinforce, at the nanoscale, a white cement mortar typically used for the restoration of monuments of cultural heritage. It was shown that sodium dodecylbenzenesulfonate (SDBS) and Triton X-100 surfactants slightly decreased the white cement mortars’ electrical resistivity (by an average of 10%), however, the mechanical properties were essentially decreased by an average of 60%. The most suitable dispersion agent for the MWCNTs proved to be the superplasticizer Ceresit CC198, and its optimal concentration was investigated for different MWCNT concentrations. Carboxylation of the MWCNT surface with nitric acid did not improve the mechanical performance of the white cement nanocomposites. The parametric experimental study showed that the optimum combination of 0.8 wt% of cement superplasticizer and 0.2 wt% of cement MWCNTs resulted in a 60% decrease in the electrical resistivity; additionally, the flexural and compressive strengths were both increased by approximately 25% and 10%, respectively.

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“…The aqueous solution was composed of (i) 0.35 MWCNTs (Industrial grade NC7000 produced by Nanocyl, Sambreville, Belgium) [30], (ii) water MilliQ (ultrapure water for laboratory) and (iii) a concentration of 10 mM of Triton TX-100 (M = 646.85 g/mol, density = 1.060 ± 0.01 g/cm 3 ) [31]. The surfactant was mixed with water MilliQ [32] by magnetic stirring for 5 min, at room temperature.…”

Section: Dispersion Of Mwcntsmentioning

confidence: 99%

“…The sonication process was carried out on a 500-watt ultrasonic processor (Sonics & Materials, Bucaramanga, Colombia) with 40% amplitude in 20 s on/off cycles to avoid overheating of the samples [33]. On the other hand, the sonication time was calculated following the work published by Mendoza-Reales [30]. The data are shown in Table 1.…”

Section: Dispersion Of Mwcntsmentioning

confidence: 99%

Time-Stability Dispersion of MWCNTs for the Improvement of Mechanical Properties of Portland Cement Specimens

et al. 2020

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This study shows the energy optimization and stabilization in the time of solutions composed of H2O + TX-100 + Multi-Wall Carbon Nanotubes (MWCNTs), used to improve the mechanical properties of Portland cement pastes. For developing this research, sonication energies at 90, 190, 290, 340, 390, 440, 490 and 590 J/g are applied to a colloidal substance (MWCNTs/TX-100 + H2O) with a molarity of 10 mM. Raman spectroscopy analyses showed that, for energies greater than 440 J/g, there are ruptures and fragmentation of the MWCNTs; meanwhile at energies below 390 J/g, better dispersions are obtained. The stability of the dispersion over time was evaluated over 13 weeks using UV-vis spectroscopy and Zeta Potential. With the most relevant data collected, sonication energies of 190, 390 and 490 J/g, at 10 mM were selected at the first and the fourth week of storage to obtain Portland cement specimens. Finally, we found an improvement of the mechanical properties of the samples built with Portland cement and solutions stored for one and four weeks; it can be concluded that the MWCNTs improved the hydration period.

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Influence of MWCNT/surfactant dispersions on the mechanical properties of Portland cement pastes

Cited by 4 publications

References 12 publications

Mechanical and electrical properties of MWCNTs - high early strength cement - mortars composite: Dispersion of CNTs and effect of chemical admixtures

Mechanical and electrical properties of MWCNTs - high early strength cement - mortars composite: Dispersion of CNTs and effect of chemical admixtures

Dispersion of Multi-Walled Carbon Nanotubes into White Cement Mortars: The Effect of Concentration and Surfactants

Time-Stability Dispersion of MWCNTs for the Improvement of Mechanical Properties of Portland Cement Specimens

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