Heating and heat-dependent mechanical characteristics of CNT-embedded cementitious composites

Kim, GM; Naeem, Faizan; Hk, Kim; Lee, Haeng‐Ki

doi:10.1016/j.compstruct.2015.10.010

Cited by 141 publications

(60 citation statements)

References 31 publications

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“…This is consistent with the recent findings by Pisello et al [14]. This is because the amount of MWCNTs used in this study was higher than the percolation threshold values (0.3–0.6 wt %) suggested by Kim et al [6]. The composites with MWCNTs also provided the highest FCR values at similar compressive loads between 10 and 30 kN.…”

Section: Test Results and Discussionsupporting

confidence: 93%

Electrical Properties of Cement-Based Composites with Carbon Nanotubes, Graphene, and Graphite Nanofibers

Yoo

You

Lee

2017

Sensors

154

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This study was conducted to evaluate the effect of the carbon-based nanomaterial type on the electrical properties of cement paste. Three different nanomaterials, multi-walled carbon nanotubes (MWCNTs), graphite nanofibers (GNFs), and graphene (G), were incorporated into the cement paste at a volume fraction of 1%. The self-sensing capacity of the cement composites was also investigated by comparing the compressive stress/strain behaviors by evaluating the fractional change of resistivity (FCR). The electrical resistivity of the plain cement paste was slightly reduced by adding 1 vol % GNFs and G, whereas a significant decrease of the resistivity was achieved by adding 1 vol % MWCNTs. At an identical volume fraction of 1%, the composites with MWCNTs provided the best self-sensing capacity with insignificant noise, followed by the composites containing GNFs and G. Therefore, the addition of MWCNTs was considered to be the most effective to improve the self-sensing capacity of the cement paste. Finally, the composites with 1 vol % MWCNTs exhibited a gauge factor of 113.2, which is much higher than commercially available strain gauges.

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Section: Test Results and Discussionsupporting

confidence: 93%

Electrical Properties of Cement-Based Composites with Carbon Nanotubes, Graphene, and Graphite Nanofibers

Yoo

You

Lee

2017

Sensors

154

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“…Additionally, the current resistivity to the initial resistivity ratio of the specimens was found to vary by only 1.0 during the heating process. It is noteworthy that no positive or negative temperature coefficient effects were observed [24][25][26]. Therefore, these four specimens can be thought of as being thermal actuators, given the stability of their resistivity.…”

Section: Electrical Resistivity and Electro-thermal Properties Of Conmentioning

confidence: 91%

Electro-thermal properties and Seebeck effect of conductive mortar and its use in self-heating and self-sensing system

Wang

Ning

et al. 2017

Ceramics International

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“…Such small cracks would neither be regarded as damage nor affect the permeability. Amongst various nanofibers, Carbon Nanotubes (CNTs) are considered as potential candidates for the next generation of high performance and multifunctional concrete structures because of their unique properties (physical, mechanical, thermal, and electrical) [18][19][20][21][22]. If CNTs are well dispersed, their high aspect ratio (length-to-diameter ratio) along with nanoscale size reduces the distance between adjacent nanotubes [23].…”

Section: Problem Statementmentioning

confidence: 99%

“…18), the increase in w/c ratio from 0.4 to 0.6 results in the significant increase in from 0.84 to 0.95 for and from 0.44 to 0.88 for (see the solid circles on the dashed lines inFigure 8-18). In addition, there are several options to achieve the same using certain combinations of w/c and s/c ratios.…”

mentioning

confidence: 95%

Design and predicting performance of carbon nanotube reinforced cementitious materials : mechanical properties and dispersion characteristics.

Ramezani¹

2020

Preprint

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Recently, Carbon Nanotubes (CNTs) are drawing considerable attention of researchers for reinforcing cementitious materials due to their excellent mechanical properties and high aspect ratio (length-to-diameter ratio). However, CNTs might not disperse well within the cement matrix, resulting in little improvement or even degradation of concrete properties. The uncertainty in producing the consistent results in different studies might be attributed to multiple interactions between the experimental variables affecting the nanotube dispersion and the final properties of CNT-cement nanocomposites. Therefore, this research mainly focused on proposing equations that can reliably capture these interactions in order to correlate CNT dispersion with the mechanical properties. The main experimental variables studied included CNT concentration, aspect ratio, ultrasonication energy, ultrasonication amplitude, surfactant-to-CNTs ratio, water-to-cement ratio, sand-to-cement ratio, and hydration age of specimen. The study reported in this research was conducted in two parts: experimental program and modeling. In the experimental part of this research, a total of 63 different mix proportions were used to evaluate the flowability, mechanical properties, and durability characteristics of cement pastes and mortars containing CNTs. Using experimental test results reported in this study and the literature, three critical relations were proposed to consider the CNT dispersion, cement matrix composition, and hydration age of cement. The proposed critical relations were then added to available theoretical models in the literature. The flexural strength and elastic modulus of CNT-cement nanocomposites were predicted through a state-of-the-art probabilistic model using a Bayesian methodology. Finally, the developed probabilistic models were used to identify the optimum ranges of the experimental variables to maximize the mechanical properties. This was done through computing the conditional probability of not meeting the specified design requirement. The experimental results indicated that addition of CNTs could significantly improve different properties of cementitious materials, if the optimum range of each variable was used. Also, to achieve the desired mechanical properties, various combinations of the experimental variables might be used. The proposed prediction models were shown to capture the interactions between the experimental variables for predicting the mechanical properties within ±15% and ±18% of the experimental test results for flexural strength and elastic modulus, respectively. Based on the findings of this research, contour plots were developed to provide practical guidelines for future engineers to design CNT-cement nanocomposites.

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Heating and heat-dependent mechanical characteristics of CNT-embedded cementitious composites

Cited by 141 publications

References 31 publications

Electrical Properties of Cement-Based Composites with Carbon Nanotubes, Graphene, and Graphite Nanofibers

Electrical Properties of Cement-Based Composites with Carbon Nanotubes, Graphene, and Graphite Nanofibers

Electro-thermal properties and Seebeck effect of conductive mortar and its use in self-heating and self-sensing system

Design and predicting performance of carbon nanotube reinforced cementitious materials : mechanical properties and dispersion characteristics.

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