Double percolation in the electrical conduction in carbon fiber reinforced cement-based materials

Wen, Sihai; Chung, D.D.L.

doi:10.1016/j.carbon.2006.09.031

Cited by 137 publications

(69 citation statements)

References 13 publications

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“…DC conductivity of 1.7 S m -1 was attained for specimen LF-M1.5. This value was greater than the electrical conductivity of 5 mm long carbon fiber-incorporated cement composites and carbon black-filled cement composites (Wen and Chung 2007;Li et al 2006). The high DC conductivity of the composites in the present section and the image analysis conducted in Sect.…”

Section: Conductivity Of the Composites Incorporating Various Mwntmentioning

confidence: 50%

Image Analysis and DC Conductivity Measurement for the Evaluation of Carbon Nanotube Distribution in Cement Matrix

Nam

Lee

2015

International Journal of Concrete Structures and Materials

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The present work proposes a new image analysis method for the evaluation of the multi-walled carbon nanotube (MWNT) distribution in a cement matrix. In this method, white cement was used instead of ordinary Portland cement with MWNT in an effort to differentiate MWNT from the cement matrix. In addition, MWNT-embedded cement composites were fabricated under different flows of fresh composite mixtures, incorporating a constant MWNT content (0.6 wt%) to verify correlation between the MWNT distribution and flow. The image analysis demonstrated that the MWNT distribution was significantly enhanced in the composites fabricated under a low flow condition, and DC conductivity results revealed the dramatic increase in the conductivity of the composites fabricated under the same condition, which supported the image analysis results. The composites were also prepared under the low flow condition (114 mm \ flow \ 126 mm), incorporating various MWNT contents. The image analysis of the composites revealed an increase in the planar occupation ratio of MWNT, and DC conductivity results exhibited dramatic increase in the conductivity (percolation phenomena) as the MWNT content increased. The image analysis and DC conductivity results indicated that fabrication of the composites under the low flow condition was an effective way to enhance the MWNT distribution.

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Section: Conductivity Of the Composites Incorporating Various Mwntmentioning

confidence: 50%

Image Analysis and DC Conductivity Measurement for the Evaluation of Carbon Nanotube Distribution in Cement Matrix

Nam

Lee

2015

International Journal of Concrete Structures and Materials

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“…In a mixture of sand and cement paste (Wen and Chung, 2007). Stromme et al (2003) reported the percolation volume of 0.238 and 0.249 for MMC equilibrated at 45 and 75% RH, respectively.…”

Section: Discussionmentioning

confidence: 99%

Ising Model for Conductive Percolation in Electrically Conductive Adhesives by Considering Random Arrangement of Conducting Particles

A.¹

2012

American Journal of Applied Sciences

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Problem statement: Thermodynamically, particles in composites will arrange in a way such that the Helmholtz free energy is minimized. However, even a single structure has the lowest free energy, it should not ignore the probability of other structures having larger energies to occur, although at small chances. Approach: All possible arrangements of particles in the composites, therefore, must be taken into account in the theory or simulation development. Results: The composite energy depends on the interaction between components in the composites. To consider the effect of interactions on energy, in this study we used a simple Ising model incorporated with the BraggWilliams approximation. We used the model to predict the average packing fraction and the percolation threshold in composites as well as other quantities related to percolation phenomenon. Conclusion/Recommendations: We found several predictions that have not been reported by previous authors. This model can be important in the understanding conductivity development in electrically conductive adhesive composites.

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“…The electrical sensitivity derives from several effects: the intrinsic resistance of carbon nanofillers and the cementitious matrix, the contact conduction among the nanotubes, and the tunneling and field emission conductions due to nanosize dimensions of the nanotubes [29,61,64]. The relationship between the variation of electrical resistance, ΔR, and the axial strain,  , can be assumed as follows (similar to the electrical strain gauges):…”

Section: Electromechanical Testsmentioning

confidence: 99%

“…Literature shows a growing interest in such nanofillers [48][49][50][51][52]. Research has studied dispersion strategies in different types of matrices [53,5454] and fabrication processes [54][55][56], and conducted experimental investigations mainly focused on quasi-static loads [57][58][59][60][61][62]. The dispersion of CNTs is an intricate task due to the presence of Van der Waals forces among the single tubes which lead to the formation of bundles [63,64].…”

Section: Introductionmentioning

confidence: 99%

An Experimental Study on Static and Dynamic Strain Sensitivity of Smart Concrete Sensors Doped with Carbon Nanotubes for SHM of Large Structures

Meoni¹,

D’Alessandro²,

Downey³

et al. 2018

Preprint

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Abstract:The availability of new self-sensing cement-based strain sensors allows the development of dense sensor networks for Structural Health Monitoring (SHM) of reinforced concrete structures. These sensors are fabricated by doping cement-matrix materials with conductive fillers, such as Multi Walled Carbon Nanotubes (MWCNTs), and can be embedded into structural elements made of reinforced concrete prior to casting. The strain sensing principle is based on the multifunctional composites outputting a measurable change in their electrical properties when subjected to a deformation. Previous work by the authors was devoted to material fabrication, modeling and applications in SHM. In this paper, we investigate the behavior of several sensors fabricated with and without aggregates and with different MWCNTs content. The strain sensitivity of the sensors, in terms of fractional change in electrical resistivity for unit strain, as well as their linearity are investigated through experimental testing under both static and dynamically varying compressive loadings. Moreover, the responses of the sensors when subjected to destructive compressive tests are evaluated. Overall, the presented results contribute to improving the scientific knowledge on the behavior of smart concrete sensors and to furthering their understanding for SHM applications.

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Double percolation in the electrical conduction in carbon fiber reinforced cement-based materials

Cited by 137 publications

References 13 publications

Image Analysis and DC Conductivity Measurement for the Evaluation of Carbon Nanotube Distribution in Cement Matrix

Image Analysis and DC Conductivity Measurement for the Evaluation of Carbon Nanotube Distribution in Cement Matrix

Ising Model for Conductive Percolation in Electrically Conductive Adhesives by Considering Random Arrangement of Conducting Particles

An Experimental Study on Static and Dynamic Strain Sensitivity of Smart Concrete Sensors Doped with Carbon Nanotubes for SHM of Large Structures

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