Synergistic effects of carbon black and steel fibers on electromagnetic wave shielding and mechanical properties of graphite/cement composites

Si, Tiantian; Xie, Shuai; Ji, Zhijiang; Ma, Chao; Wu, Zihao; Wu, Jian; Wang, Jing

doi:10.1016/j.jobe.2021.103561

Cited by 15 publications

(5 citation statements)

References 64 publications

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“…The composite conductive network consisting of carbon fibers and graphite exhibits the highest current and temperature under low voltages (less than 9 V). This result is due to the three‐dimensional conductive network formed by the combination of fibers and powders, which enables optimal electrical conductivity 59 . However, the high electrical conductivity of the composite network under high voltages leads to a high current, resulting in a rapid rise in temperature.…”

Section: Discussionmentioning

confidence: 99%

Electrothermal effect of carbon fiber and graphite reinforced metakaolin‐based geopolymer

Zhang,

Lin,

Chen

et al. 2024

Int J Applied Ceramic Tech

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This paper investigates the influence of carbon fiber and graphite on the cyclic electrothermal performance of geopolymers (inorganic polymers). It was observed that carbon fibers, graphite, and the carbon fiber/graphite composite could form a stable conductive network at low voltage (3 V). However, under high voltages (9 and 12 V), the current of the geopolymer exhibited a peak shape in the first cycle, with higher voltages resulting in larger peak values and decreased conductivity in subsequent cycles. While graphite improved electrical and thermal conductivity, it weakened the microstructure, leading to an increase in microcracks and voids, and a reduction in the strength of geopolymers. The cumulative energy during the electrothermal process was calculated. The failure mechanism of the conductive network in the geopolymer during cyclic electrical heating was explained, highlighting the disruptive effect of gel shrinkage due to water loss on conductive networks.

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Section: Discussionmentioning

confidence: 99%

Electrothermal effect of carbon fiber and graphite reinforced metakaolin‐based geopolymer

Zhang,

Lin,

Chen

et al. 2024

Int J Applied Ceramic Tech

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“…To further validate the impact of alkaline activation technology on the attenuation constant and impedance matching of rice husk ash-foamed concrete when subjected to electromagnetic wave incidence, the reflection loss of alkaline-activated rice husk ashfoamed concrete is calculated using transmission line theory [52]: To assess whether an electromagnetic wave-absorbing material is suitable for practical engineering, it must have a Reflection Loss (RL) of less than or equal to -10 dB. This indicates that the material absorbs over 90% of the electromagnetic wave [53]. Figure 14 shows a three-dimensional representation and a mapped planar view of the reflection loss for specimens N0 and N1 against incident electromagnetic waves in the frequency range of 2-18 GHz.…”

Section: Fig12 Attenuation Constant Of N0、n3 and N1mentioning

confidence: 99%

Alkali-activated Rice Husk Ash-Foamed Concrete: Correlation between Microporous Structure, Hydration Characteristics and Hardening Properties

Bai,

Xie,

Chen

2024

Preprint

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Solid waste recycling plays a crucial role in environmental protection and energy conservation. This study explores the utilization of rice husk ash as an auxiliary binding material in the production of alkali-activated foamed concrete. The impact of the modulus of the alkaline activator on the dry density, water absorption rate, thermal conductivity, electromagnetic wave absorption, and compressive and flexural strength of rice husk ash-foamed concrete was investigated. Additionally, the foamed concrete's micro-pore structure and hydration characteristics were characterized. For the first time, the study reveals the correlation between the pore structure, hydration products, and hardening properties of alkali-activated rice husk ash-foamed concrete. The results demonstrate that with a decrease in the modulus of the alkaline activator, the presence of accessible OH- ions in the colloid increases, leading to an improvement in the pore structure of alkali-activated rice husk ash-foam concrete and an increase in hydration products. The reduction in interconnected pores, increase in tiny pores, and higher C-S-H gel and ettringite content in the hydration products directly impact the development of concrete strength, reduction in dry density and water absorption rate, and decrease in thermal conductivity. Alkaline activation, through optimizing the pore structure, enhances the attenuation constant and impedance matching of the alkali-activated rice husk ash-foam concrete matrix, enhancing its electromagnetic wave absorption capability. In conclusion, the overall results suggest that alkali-activated rice husk ash-foam concrete is a viable material for energy-efficient and environmentally friendly construction.

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“…Reflection loss (RL) is a criterion for the electromagnetic wave absorption characteristics of single-layer planar materials, as in equation 7, and a value of less than -10 dB indicates that more than 90% of the electromagnetic wave is absorbed by the material [41]. The results of RL calculations for three sets of specimens from 0 to 10 mm thickness are shown in Figures 17 to 19 17 that the Group O has almost no electromagnetic wave loss capability and the reflection loss value reaches its minimum value of -3.58 dB at a thickness of 10 mm.…”

Section: Electromagnetic Characteristicsmentioning

confidence: 99%

Preparation of a novel foamed concrete modified with carbon fiber and graphite:

Tu,

Xia,

et al. 2024

Preprint

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In this paper, foam concrete is modified using graphite and carbon fiber as absorbents. The mechanical properties of the foam concrete are analysed in conjunction with hydration products, pore size distribution based on SEM test and XCT test. Further, the resistivity, complex permittivity and complex permeability are tested. The results demonstrate that carbon fiber enhance the proportion of pores with diameters less than 200µm in foam concrete, thereby substantially enhancing its flexural strength. Besides, adding graphite offsets the initial retardation of sulfoaluminate cement hydration induced by carbon fibers, which increases the average pore size of carbon fiber-reinforced foam concrete, reducing the compressive strength. The addition of carbon fibers at a concentration of 0.6wt.% achieves the percolation threshold, akin to scenarios with singular fiber incorporation. Exceeding 2wt% graphite content results in negligible influence on the conductivity of the carbon fiber-reinforced foam concrete.

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Synergistic effects of carbon black and steel fibers on electromagnetic wave shielding and mechanical properties of graphite/cement composites

Cited by 15 publications

References 64 publications

Electrothermal effect of carbon fiber and graphite reinforced metakaolin‐based geopolymer

Electrothermal effect of carbon fiber and graphite reinforced metakaolin‐based geopolymer

Alkali-activated Rice Husk Ash-Foamed Concrete: Correlation between Microporous Structure, Hydration Characteristics and Hardening Properties

Preparation of a novel foamed concrete modified with carbon fiber and graphite:

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