The investigation of multi-walled carbon nanotubes dispersion and its influence on rheological properties of cement systems

The current research is devoted to the studying of multi-walled carbon nanotubes (MWCNT) dispersion and its influence on the rheological properties of cement pastes. The pH and electrical conductivity test, zeta potential measurements, particle size analysis were performed for characterization of MWCNT dispersion. The MWCNT dispersion were tested during 1 month and presented the decrease of pH level from 8.89 to 8.02, increase of electrical conductivity from 2.00 to 2.75 mS/cm. The particle size analysis did not reveal the significant changes during 1 month of storage. The rheological test of nanomodified cement pastes were performed for concentration of MWCNT dispersion in the range from 0 to 0.5% by weight of cement. The decrease of yield stress by 30.7% and increase of plastic viscosity by 29.6% were obtained for cement paste modified by MWCNT dispersion in dosage of 0.25% by weight of cement. The changes in flow behaviour were established for cement pastes tested in 5 min after mixing and were not observed for cement pastes tested after 120 min of mixing.

Download Full-text

The effect of multi-walled carbon nanotubes on the rheological properties and hydration process of cement pastes

Construction and Building Materials ◽

10.1016/j.conbuildmat.2018.09.082 ◽

2018 ◽

Vol 189 ◽

pp. 947-954 ◽

Cited By ~ 8

Author(s):

Dainius Leonavičius ◽

Ina Pundienė ◽

Giedrius Girskas ◽

Jolanta Pranckevičienė ◽

Modestas Kligys ◽

...

Keyword(s):

Carbon Nanotubes ◽

Rheological Properties ◽

Hydration Process ◽

Cement Pastes ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes

Download Full-text

Effect of Ball-Milling Parameter on the Synthesis of MWCNT/Alumina Hybrid Compound

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.620.309 ◽

2012 ◽

Vol 620 ◽

pp. 309-313 ◽

Cited By ~ 1

Author(s):

Norlin Nosbi ◽

Md Akil Hazizan

Keyword(s):

Carbon Nanotubes ◽

Ball Milling ◽

Particle Size Analysis ◽

Methane Decomposition ◽

Decomposition Process ◽

Size Analysis ◽

Hybrid Compound ◽

X Ray ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes

The effects of ball-milling parameter on the structures and properties of the synthesis of multi-walled carbon nanotubes (MWCNT)/alumina hybrid compound via methane decomposition process using Ni-Alumina catalyst were researched. The structural evaluation of particles compound was investigated by particle size analysis, energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), FTIR spectrometer and scanning electron microscopy (SEM). The results indicated that with 300rpm 15h, the microstructure of the hybrid compound is greatly refined, and methane decomposition process distributed uniformly, thus increasing the efficiency of the carbon nanotubes growth process.

Download Full-text

Enhancement of Electrical Conductivity of Aluminum-Based Nanocomposite Produced by Spark Plasma Sintering

Nanomaterials ◽

10.3390/nano11051150 ◽

2021 ◽

Vol 11 (5) ◽

pp. 1150

Author(s):

Nicolás A. Ulloa-Castillo ◽

Roberto Hernández-Maya ◽

Jorge Islas-Urbano ◽

Oscar Martínez-Romero ◽

Emmanuel Segura-Cárdenas ◽

...

Keyword(s):

Carbon Nanotubes ◽

Electrical Conductivity ◽

Spark Plasma Sintering ◽

Experimental Tests ◽

Powder Morphology ◽

Plasma Sintering ◽

Multi Walled Carbon Nanotubes ◽

Spark Plasma ◽

Ball Milling Technique ◽

Walled Carbon Nanotubes

This article focuses on exploring how the electrical conductivity and densification properties of metallic samples made from aluminum (Al) powders reinforced with 0.5 wt % concentration of multi-walled carbon nanotubes (MWCNTs) and consolidated through spark plasma sintering (SPS) process are affected by the carbon nanotubes dispersion and the Al particles morphology. Experimental characterization tests performed by scanning electron microscopy (SEM) and by energy dispersive spectroscopy (EDS) show that the MWCNTs were uniformly ball-milled and dispersed in the Al surface particles, and undesirable phases were not observed in X-ray diffraction measurements. Furthermore, high densification parts and an improvement of about 40% in the electrical conductivity values were confirmed via experimental tests performed on the produced sintered samples. These results elucidate that modifying the powder morphology using the ball-milling technique to bond carbon nanotubes into the Al surface particles aids the ability to obtain highly dense parts with increasing electrical conductivity properties.

Download Full-text

Study of Rheological Properties of Carbon Nanotube-Reinforced Ultrafine Cement Grouting Materials

Magazine of Concrete Research ◽

10.1680/jmacr.21.00005 ◽

2021 ◽

pp. 1-44

Author(s):

Yunxiao Liu ◽

Jiahang Zhang ◽

Yinyin Chi

Keyword(s):

Carbon Nanotubes ◽

Rheological Properties ◽

Polyvinyl Pyrrolidone ◽

Cement Grouting ◽

Grouting Material ◽

Multi Walled Carbon Nanotubes ◽

Different Diameters ◽

Grouting Materials ◽

Walled Carbon Nanotubes ◽

Ultrafine Cement

In this study, three different diameters of multi-walled carbon nanotubes (MWCNTs) dispersed by polyvinyl pyrrolidone (PVP) were used to reinforce superfine cement grouting materials. The effect of MWCNTs and polyvinyl pyrrolidone (PVP) on the rheological properties of grouting material were accordingly studied. It was found that the yield stress (τ0) and plastic viscosity (η) were slightly decreased when PVP content was low and increased when the PVP content increased. The effect of MWCNT diameter on τ0 was not found to be clear but was more significant on η. The smaller MWCNT diameter was, the more quickly η increase. It was also found that the thixotropic ring area was increased as the MWCNTs content increased. The addition of PVP and MWCNTs caused an increase in the number of entanglement points in different scales, which was the main reason for the viscosity and thixotropy increase. Therefore, the rheological properties of superfine cement grouting material should be adjusted when MWCNTs were added as a reinforcing component. Due to the wrapping of PVP on cement particles which isolates the contacting part between the water and the cement particles, it slows down the cement's hydration rate thus slows down the fluidity loss of the slurry.

Download Full-text

Synthesis, Characterization and Study of DC Electrical Conductivity of Poly[MWCNT/Imidoselenium] Composite

10.26434/chemrxiv.11441313 ◽

2019 ◽

Author(s):

Abeer O. Obeid ◽

Fatma Al-Yusufy ◽

Sama A Al-Aghbari ◽

omar alshujaa ◽

Yassin Gaber ◽

...

Keyword(s):

Carbon Nanotubes ◽

Electrical Conductivity ◽

Selenium Dioxide ◽

Chemical Functionalization ◽

Dc Electrical Conductivity ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes

The chemical functionalization of amino multi-walled carbon nanotubes (MWCNT-NH2) by selenium dioxide (SeO2) was used to produce Poly [MWCNT/Imidoselenium] composite. The prepared poly-composite was characterized by FTIR, SEM, TEM, XRD, UV, DSC and TGA. The DC electrical conductivity of poly-composite was 4.3×10-4 S/cm due to the interaction between the nanotubes.

Download Full-text

Effects of Tailings Gradation on Rheological Properties of Filling Slurry

Advances in Civil Engineering ◽

10.1155/2019/6873840 ◽

2019 ◽

Vol 2019 ◽

pp. 1-11 ◽

Cited By ~ 1

Author(s):

Bingwen Wang ◽

Tingyong Xiong ◽

Lijing Gao ◽

Yuepeng Chai ◽

Xiangyu Cui ◽

...

Keyword(s):

Particle Size ◽

System Design ◽

Rheological Properties ◽

Particle Size Analysis ◽

Size Analysis ◽

Analysis Software ◽

Key Technology ◽

Fine Grained ◽

Viscosity Coefficients ◽

Filling System

The key technology in filling mining is the gravity transportation of high-density slurries, and the filling system design is a significant part of this technology. The filling effect depends on the fluidity of the filling slurry. To investigate the influence of the gradation of tailings on the rheological properties of the filling slurry, this study uses particle size analysis to prepare three types of tailings: powder-, relatively fine-, and fine-grained tailings, which are then mixed in different proportions. The rheological properties of the resulting filling slurries are tested; the viscosity coefficients and yield stresses of the slurries are obtained using the analysis software provided with the MCR102 advanced rheometer that is used to measure the rheological properties of the slurries. The experimental results demonstrate that there is no absolute relationship between the rheological properties of the slurry and the size of the tailings particles, but the rheological properties are related to the gradation of tailings. Lubricating effect is weakened with an insufficient content of powder-grained particles in the tailings. On the contrary, when the content of powder-grained particles in the tailings is too high, the viscous substances in the slurry increase. Both of these conditions can increase the friction loss of the slurry.

Download Full-text