Characterizing dispersion and long term stability of concentrated carbon nanotube aqueous suspensions for fabricating ductile cementitious composites

Parveen, Shama; Rana, Sohel; Fangueiro, Raúl; Paiva, Maria C.

doi:10.1016/j.powtec.2016.11.010

Cited by 32 publications

(30 citation statements)

References 40 publications

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“…In fact, their role as a moisture regulator is more effective in increasing the slipperiness of cement and sand grains, and consequently, in CSS density improvement. CNTs and GNPs absorb and decrease the free water among the cement and sand grains, and also prevent the inhomogeneous distribution of water [ 29 , 39 ]. In addition, these nano-scaled particles with a water-impregnated surface and high aspect ratio encourage the slipping and latching of cement and sand grains together ( Figure 8 ).…”

Section: Resultsmentioning

confidence: 99%

Development of a Novel Multifunctional Cementitious-Based Geocomposite by the Contribution of CNT and GNP

2021

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In this study, a self-sensing cementitious stabilized sand (CSS) was developed by the incorporation of hybrid carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) based on the piezoresistivity principle. For this purpose, different concentrations of CNTs and GNPs (1:1) were dispersed into the CSS, and specimens were fabricated using the standard compaction method with optimum moisture. The mechanical and microstructural, durability, and piezoresistivity performances, of CSS were investigated by various tests after 28 days of hydration. The results showed that the incorporation of 0.1%, 0.17%, and 0.24% CNT/GNP into the stabilized sand with 10% cement caused an increase in UCS of about 65%, 31%, and 14%, respectively, compared to plain CSS. An excessive increase in the CNM concentration beyond 0.24% to 0.34% reduced the UCS by around 13%. The addition of 0.1% CNMs as the optimum concentration increased the maximum dry density of the CSS as well as leading to optimum moisture reduction. Reinforcing CSS with the optimum concentration of CNT/GNP improved the hydration rate and durability of the specimens against severe climatic cycles, including freeze–thaw and wetting–drying. The addition of 0.1%, 0.17%, 0.24%, and 0.34% CNMs into the CSS resulted in gauge factors of about 123, 139, 151, and 173, respectively. However, the Raman and X-ray analysis showed the negative impacts of harsh climatic cycles on the electrical properties of the CNT/GNP and sensitivity of nano intruded CSS.

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Section: Resultsmentioning

confidence: 99%

Development of a Novel Multifunctional Cementitious-Based Geocomposite by the Contribution of CNT and GNP

2021

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“…The higher the values of zeta potential indicate the degree of repulsion between oxidized graphene nanoparticles in the solvent. As a result, good dispersion of GO without any agglomeration and aggregation was achieved 31 . These results further signify that the electrical double layer consisting of a rigid layer bonded to particles and the electrostatic repulsion produced by the diffused layer, which overcomes van der Waals forces resulting in a homogenous solution of GO.…”

Section: Characterization Studiesmentioning

confidence: 92%

Graphene/PVA buckypaper for strain sensing application

Mehmood

Mubarak

Khalid

et al. 2020

Sci Rep

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Strain sensors in the form of buckypaper (BP) infiltrated with various polymers are considered a viable option for strain sensor applications such as structural health monitoring and human motion detection. Graphene has outstanding properties in terms of strength, heat and current conduction, optics, and many more. However, graphene in the form of BP has not been considered earlier for strain sensing applications. In this work, graphene-based BP infiltrated with polyvinyl alcohol (PVA) was synthesized by vacuum filtration technique and polymer intercalation. First, Graphene oxide (GO) was prepared via treatment with sulphuric acid and nitric acid. Whereas, to obtain high-quality BP, GO was sonicated in ethanol for 20 min with sonication intensity of 60%. FTIR studies confirmed the oxygenated groups on the surface of GO while the dispersion characteristics were validated using zeta potential analysis. The nanocomposite was synthesized by varying BP and PVA concentrations. Mechanical and electrical properties were measured using a computerized tensile testing machine, two probe method, and hall effect, respectively. The electrical conducting properties of the nanocomposites decreased with increasing PVA content; likewise, electron mobility also decreased while electrical resistance increased. The optimization study reports the highest mechanical properties such as tensile strength, Young’s Modulus, and elongation at break of 200.55 MPa, 6.59 GPa, and 6.79%, respectively. Finally, electrochemical testing in a strain range of ε ~ 4% also testifies superior strain sensing properties of 60 wt% graphene BP/PVA with a demonstration of repeatability, accuracy, and preciseness for five loading and unloading cycles with a gauge factor of 1.33. Thus, results prove the usefulness of the nanocomposite for commercial and industrial applications.

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“…Pluronic F-127 is a non-ionic triblock copolymer surfactant composed of two hydrophilic chains of polyoxyethylene (PEO) which placed in two sides of a central polyoxypropylene (PPO) hydrophobic chain. These side chains of hydrophilic PEO are similar to superplasticizers of polycarboxylate which are typically used in cementitious composites [33]. For this reason, Pluronic F-127 was found to be compatible with cementitious composites and could possibly improve its mechanical behavior and dry bulk density due to improved fluidity of the mortar.…”

Section: Introductionmentioning

confidence: 95%

Ultra-Sensitive Affordable Cementitious Composite with High Mechanical and Microstructural Performances by Hybrid CNT/GNP

2020

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In this paper a hybrid combination of carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) was used for developing cementitious self-sensing composite with high mechanical, microstructural and durability performances. The mixture of these two nanoparticles with different 1D and 2D geometrical shapes can reduce the percolation threshold to a certain amount which can avoid agglomeration formation and also reinforce the microstructure due to percolation and electron quantum tunneling amplification. In this route, different concentrations of CNT + GNP were dispersed by Pluronic F-127 and tributyl phosphate (TBP) with 3 h sonication at 40 °C and incorporated into the cementitious mortar. Mechanical, microstructural, and durability of the reinforced mortar were investigated by various tests in different hydration periods (7, 28, and 90 days). Additionally, the piezoresistivity behavior of specimens was also evaluated by the four-probe method under flexural and compression cyclic loading. Results demonstrated that hybrid CNT + GNP can significantly improve mechanical and microstructural properties of cementitious composite by filler function, bridging cracks, and increasing hydration rate mechanisms. CNT + GNP intruded specimens also showed higher resistance against climatic cycle tests. Generally, the trend of all results demonstrates an optimal concentration of CNT (0.25%) + GNP (0.25%). Furthermore, increasing CNT + GNP concentration leads to sharp changes in electrical resistivity of reinforced specimens under small variation of strain achieving high gauge factor in both flexural and compression loading modes.

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Characterizing dispersion and long term stability of concentrated carbon nanotube aqueous suspensions for fabricating ductile cementitious composites

Cited by 32 publications

References 40 publications

Development of a Novel Multifunctional Cementitious-Based Geocomposite by the Contribution of CNT and GNP

Development of a Novel Multifunctional Cementitious-Based Geocomposite by the Contribution of CNT and GNP

Graphene/PVA buckypaper for strain sensing application

Ultra-Sensitive Affordable Cementitious Composite with High Mechanical and Microstructural Performances by Hybrid CNT/GNP

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