scholarly journals Effect of carbon nanotubes sonication on mechanical properties of cement pastes

2020 ◽  
Vol 13 (2) ◽  
pp. 455-463
Author(s):  
J. E. L. de SIQUEIRA ◽  
P. J. P. GLEIZE
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
High Energy ◽  
High Specific Surface Area ◽  
Cement Pastes ◽  
Water Suspensions ◽  
Vis Spectroscopy ◽  
Dispersion Problem ◽  
Compressive And Flexural Strengths ◽  
Sonication Parameters

Abstract The excellent mechanical properties of carbon nanotubes (CNTs) make them a highly attractive material for use as reinforcement in cement composites. However, it is established that this nanomaterial presents a severe dispersion problem in cement matrices owing to its high specific surface area. An alternative method for dispersing the CNTs is the use of sonication in the presence of a superplasticizer admixture. However, high energy sonication can severely damage CNTs, which can affect their behavior in cement pastes. Thus, it is necessary to optimize the CNTs sonication parameters to optimize the performance of CNT-cement pastes. After sonication with different energies of CNTs water suspensions, the CNTs dispersion was evaluated through UV-Vis spectroscopy and the eventual CNTs damage observed by TEM. Workability, compressive and flexural strengths of the CNTs-cement pastes were also measured. The results revealed that the sonication parameters can be optimized to enhance the effect of CNTs on cement paste behavior.

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

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4149
Author(s):  
Laura M. Echeverry-Cardona ◽  
Natalia Álzate ◽  
Elisabeth Restrepo-Parra ◽  
Rogelio Ospina ◽  
Jorge H. Quintero-Orozco
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Raman Spectroscopy ◽  
Portland Cement ◽  
Time Stability ◽  
Cement Pastes ◽  
Multi Wall Carbon Nanotubes ◽  
Vis Spectroscopy ◽  
The Stability ◽  
Over Time

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.

scholarly journals Effect of Increasing the Strength of Aluminum Matrix Nanocomposites Reinforced with Microadditions of Multiwalled Carbon Nanotubes Coated with TiC Nanoparticles

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1596 ◽  
Author(s):  
Artemiy Aborkin ◽  
Kirill Khorkov ◽  
Evgeny Prusov ◽  
Anatoly Ob’edkov ◽  
Kirill Kremlev ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Aluminum Matrix ◽  
High Energy ◽  
High Tech ◽  
Multiwalled Carbon ◽  
The Matrix ◽  
Tic Nanoparticles ◽  
Matrix Nanocomposites

Aluminum matrix composites reinforced with multiwalled carbon nanotubes (MWCNTs) are promising materials for applications in various high-tech industries. Control over the processes of interfacial interaction in Al/MWCNT composites is important to achieve a high level of mechanical properties. The present study describes the effects of coating MWCNTs with titanium carbide nanoparticles on the formation of mechanical properties and the evolution of the reinforcement structure in bulk aluminum matrix nanocomposites with low concentrations of MWCNTs under conditions of solid-phase consolidation of ball-milled powder mixtures. Using high-energy ball milling and uniaxial hot pressing, two types of bulk nanocomposites based on aluminum alloy AA5049 that were reinforced with microadditions of MWCNTs and MWCNTs coated with TiC nanoparticles were successfully produced. The microstructural and mechanical properties of the Al/MWCNT composites were investigated. The results showed that, on the one hand, the TiC nanoparticles on the surface of the MWCNT hybrid reinforcement reduced the damage of reinforcement under the intense exposure of milling bodies, and on the other hand, they reduced the contact area of the MWCNTs with the matrix material (acting as a barrier interface), which also locally inhibited the reaction between the matrix and the MWCNTs.

scholarly journals Dispersion of Carbon Nanotubes with Different Types of Superplasticizer as a Dispersing Agent for Self-Sensing Cementitious Materials

2021 ◽  
Vol 11 (18) ◽  
pp. 8452
Author(s):  
Pedro de Almeida Carísio ◽  
Yasmim Gabriela dos Santos Mendonça ◽  
Carlos Fernando Teodósio Soares ◽  
Oscar Aurelio Mendoza Reales ◽  
Eduardo de Moraes Rego Fairbairn ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Cementitious Materials ◽  
Cement Matrix ◽  
Cement Pastes ◽  
Sensing Applications ◽  
Dispersing Agent ◽  
Vis Spectroscopy ◽  
Different Types ◽  
Conductive Fillers ◽  
Dispersing Agents

Due to their exceptional electrical properties, carbon nanotubes (CNTs) can be applied as conductive fillers to develop self-sensing cement-based matrices. In order to obtain an adequate self-sensing response, CNTs must be evenly dispersed through the cement matrix in a volume sufficient enough to create an electric percolation network. This is challenged by the difficulty of dispersing CNTs; therefore, there is a demand for an efficient dispersing agent that can be filled by superplasticiezers, which are products of known compatibility with cement and high availability. This research explores the use of four commercial superplasticizers available in Brazil, both naphthalene and ether polycarboxylate-based, as dispersing agents for CNTs in water. Ultrasonic energy was applied to aqueous solutions containing CNTs and superplasticizers. UV–Vis spectroscopy and ξ-potential measurements were used to investigate which superplasticizer was more effective to disperse the CNTs. Cement pastes were produced with the CNT dispersions and their electrical resistivity was measured. It was found that only superplasticizers without aliphatic groups in their structure were capable of dispersing CNTs in water. It was concluded that second-generation naphthalene-based superplasticizers were more efficient dispersing agents for CNTs than third-generation ether polycarboxylate-based ones for self-sensing applications.

scholarly journals Enhanced Thermal Stability, Mechanical Properties and Structural Integrity of MWCNT Filled Bamboo/Kenaf Hybrid Polymer Nanocomposites

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 506
Author(s):  
J. M. Prabhudass ◽  
K. Palanikumar ◽  
Elango Natarajan ◽  
Kalaimani Markandan
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Energy Absorption ◽  
Epoxy Matrix ◽  
Structural Integrity ◽  
High Energy ◽  
Natural Fibre ◽  
Impact Testing ◽  
Hibiscus Cannabinus ◽  
Natural Fibres

Recently, there has been an inclination towards natural fibre reinforced polymer composites owing to their merits such as environmental friendliness, light weight and excellent strength. In the present study, six laminates were fabricated consisting of natural fibres such as Kenaf fibre (Hibiscus cannabinus L.) and Bamboo fibre, together with multi-walled carbon nanotubes (MWCNTs) as reinforcing fillers in the epoxy matrix. Mechanical testing revealed that hybridization of natural fibres was capable of yielding composites with enhanced tensile properties. Additionally, impact testing showed a maximum improvement of ≈80.6% with the inclusion of MWCNTs as nanofiller in the composites with very high energy absorption characteristics, which were attributed to the high specific energy absorption of carbon nanotubes. The viscoelastic behaviour of hybridised composites reinforced with MWCNTs also showed promising results with a significant improvement in the glass transition temperature (Tg) and 41% improvement in storage modulus. It is worth noting that treatment of the fibres in NaOH solution prior to composite fabrication was effective in improving the interfacial bonding with the epoxy matrix, which, in turn, resulted in improved mechanical properties.

scholarly journals Quantifying the Difference of Uniformly Dispersed and Re-agglomerated Graphene Oxide-Based Cement Pastes on Rheological and Mechanical Properties

2018 ◽  
Vol 206 ◽  
pp. 03003
Author(s):  
Haodao Li ◽  
Jingjie Wei ◽  
Wujian Long
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Cement Paste ◽  
Mercury Intrusion Porosimetry ◽  
Large Diameter ◽  
Cement Pastes ◽  
The Difference ◽  
Compressive And Flexural Strengths ◽  
Porosity Analysis ◽  
Better Than

The state of GO dispersion is closely related to the properties of graphene oxide (GO)-based cement paste. This paper presents the effect of uniformly dispersed and re-agglomerated GO on the rheological and mechanical properties. The results showed that, compared to re-agglomerated GO cement paste, the yield stress and plastic viscosity of uniformly dispersed GO cement paste were higher. Moreover, the compressive and flexural strengths of uniformly dispersed GO pastes were higher than those of re-agglomerated GO pastes. Porosity analysis using mercury intrusion porosimetry showed that the well-dispersed GO can inhibit the formation of large-diameter pores and optimize the pore size distribution better than the re-agglomerated GO.

Effects of Rubber Particles on Rheological and Mechanical Properties of Concrete Containing CaCO3 Nanoparticles

2018 ◽  
Vol 926 ◽  
pp. 109-114
Author(s):  
Li Wang ◽  
Ben Dong Zhao
Keyword(s):  
Mechanical Properties ◽  
Fine Aggregate ◽  
Rubberized Concrete ◽  
Cement Pastes ◽  
Effective Strategies ◽  
Waste Rubber ◽  
Fine Aggregates ◽  
Strength Tests ◽  
Rubber Particles ◽  
Compressive And Flexural Strengths

Lots of waste rubber is being produced in the world and the utilization of it not only mitigate environmental impacts caused by waste rubber disposal but also enhance sustainable development. As a result, rubberized concrete, by incorporation of waste rubber into concrete, should be considered as one of the effective strategies to take advantage of waste rubber. However, problems such as low strengths, weak adhesion between rubber particles and cement pastes, and undesirable pore structures associated with rubberized concrete should be pay more attention to. In this study, the effect of replacement fine aggregate with rubber particles on rheological and mechanical properties of concrete containing CaCO3 nanoparticles was examined through slump, compressive and flexural strength tests. Rubber particles were employed to replace the fine aggregate equally by volume while CaCO3 nanoparticles were used as an equal part of binder by weight. Different sizes and volume contents of rubber particles were evaluated as well as different weight contents of CaCO3 nanoparticles. In addition, corresponding tests were also performed to evaluate the effect of CaCO3 nanoparticles in comparison to concrete specimens without CaCO3 nanoparticles. The results showed that replacement fine aggregates with rubber particles had some influence on the mechanical properties of rubberized concrete, resulting in undesirable findings in terms of compressive and flexural strengths. However, the incorporation of CaCO3 nanoparticles improved mechanical properties of rubberized concrete. Regarding slump test, the rubberized concrete without CaCO3 nanoparticles showed better performance. Considering rheological and mechanical properties, rubberized concrete with 1% CaCO3 nanoparticles presented acceptable results.

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

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5248
Author(s):  
Laura Silvestro ◽  
Artur Ruviaro ◽  
Geannina Lima ◽  
Paulo de Matos ◽  
Afonso R. G. de Azevedo ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Compressive Strength ◽  
Portland Cement ◽  
Mechanical Performance ◽  
Isothermal Calorimetry ◽  
Hydration Kinetics ◽  
Cement Pastes ◽  
Degree Of Hydration ◽  
Vis Spectroscopy ◽  
Localized Defects

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.

PVA/MWNTs Composite Nanofibers Prepared by Electrospun

2010 ◽  
Vol 44-47 ◽  
pp. 2377-2380
Author(s):  
Hui Qin Zhang ◽  
Ai Mei Li
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Thermal Stability ◽  
Fourier Transform ◽  
Composite Nanofibers ◽  
Multiwall Carbon Nanotubes ◽  
High Energy ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
Multiwall Carbon

The Polyvinyl alcohol (PVA)/ multiwall carbon nanotubes (MWNT) nanofibers were prepared by electrospun assisted by high-energy sonication. The morphological structures and characterized of the nanofibers were observed via scanning electronic microscopy (SEM), thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR). Electrical properties and mechanical properties of the film have been tested. The results indicate that the introduction of ATO nanoparticles into the polymer matrix has a significant effect on the thermal stability properties of PVA and a strong interaction between PVA and MWNTs.

scholarly journals Experimental study of the behaviour of cement pastes in the presence of carbon nanotubes

2019 ◽  
Author(s):  
Ritoltas Šukys ◽  
Jolanta Pranckevičienė ◽  
Giedrius Girskas ◽  
Ina Pundienė ◽  
Dainius Leonavičius ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Dynamic Viscosity ◽  
Methyl Cellulose ◽  
Physical And Mechanical Properties ◽  
Previous Treatment ◽  
Cementitious Materials ◽  
Mechanical Tests ◽  
Cement Pastes ◽  
Multi Walled Carbon Nanotubes ◽  
Compressive And Flexural Strengths

One of the methods recently applied for the noticeably improvement of properties of cementitious materials is the use of the single or multi-walled carbon nanotubes (CNTs) as nano-reinforcements in cementitious materials. The positive action of CNTs highly depends not only on its nature, length and amount, but also on previous treatment of CNTs and quality of CNTs dispersion. It is important to obtain the effects of multi-walled CNTs, dispersed only in carboxyl-methyl cellulose – commercially available pellets without the use of any commercially available surfactants or plasticizers. The influence of dispersed CNTs on the rheological properties of fresh cement pastes and physical and mechanical properties of hardened specimens was analyzed in this work. Compared to the dynamic viscosity of pure distilled water smaller amounts of CNTs (0.00005–0.005%) reduce the dynamic viscosity down to the 15% whereas higher amounts of CNTs (0.05–0.5%) increase the dynamic viscosity from 1.3 to 4.7 times. Mechanical tests of hardened for 28 days cement paste specimens showed that smaller amounts of CNTs (0.00005–0.005%) increase the compressive and flexural strengths by 38.07– 42.3% and 40.1– 44.6%, whereas higher amounts of CNTs (0.05–0.5%) increase these strengths just by 21.11–18.82% and 18.33–6.6% respectively.

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