• Title/Summary/Keyword: conductive concrete

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A study on electrical and thermal properties of conductive concrete

  • Wu, Tehsien;Huang, Ran;Chi, Maochieh;Weng, Tsailung
    • Computers and Concrete
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    • v.12 no.3
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    • pp.337-349
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    • 2013
  • Traditional concrete is effectively an insulator in the dry state. However, conductive concrete can attain relatively high conductivity by adding a certain amount of electronically conductive components in the regular concrete matrix. The main purpose of this study is to investigate the electrical and thermal properties of conductive concrete with various graphite contents, specimen dimensions and applied voltages. For this purpose, six different mixtures (the control mixtures and five conductive mixtures with steel fibers of 2% by weight of coarse aggregate and graphite as fine aggregate replacement at the levels of 0%, 5%, 10%, 15% and 20% by weight) were prepared and concrete blocks with two types of dimensions were fabricated. Four test voltage levels, 48 V, 60 V, 110 V, and 220 V, were applied for the electrical and thermal tests. Test results show that the compressive strength of specimens decreases as the amount of graphite increases in concrete. The rising applied voltage decreases electrical resistivity and increases heat of concrete. Meanwhile, higher electrical current and temperature have been obtained in small size specimens than the comparable large size specimens. From the results, it can be concluded that the graphite contents, applied voltage levels, and the specimen dimensions play important roles in electrical and thermal properties of concrete. In addition, the superior electrical and thermal properties have been obtained in the mixture adding 2% steel fibers and 10% graphite.

A study on the Properties of Cement Mortar Containing Electrically Conductive Materials (전기전도성 재료를 혼입한 시멘트 모르타르의 전기적 특성에 관한 연구)

  • 최길섭;소양섭
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.10b
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    • pp.933-938
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    • 2000
  • Concrete has been used for many years as a composite material that has excellent mechanical properties and durability for construction. However, concrete is a poor electrical conductor, especially under dry conditions. Concrete that is excellent in both mechanical and electrical conductivity properties may have important applications in the electrical, electronic, military and construction industry(e.g. for de-icing road from snow). The purpose of this investigation is to improve the electrical conductive of cement mortar preparared with coke dust, graphite, carbon black and carbon fiber as filler. From the test result, as the content of electrically conductive material increased, fluidity and strength decreased but resistivity decreased. The resistivity of electrical conductive cement mortar is effect by water/cement, and aggregate. Cement mortar containing carbon fiber has the best electrical properties considering strength. From this study, it is enough to assure the use of carbon fiber, carbon black and graphite as a conductive filler for electrical conductive cement mortar.

A Study on the Properties of Electrical Conductive Cement Mortar (전지전도성 시멘트모르타르의 특성에 관한 연구)

  • Choi, Gil-Seob;Kim, Bong-Chan;Kim, Wan-Ki;Soh, Yang-Seob
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.04a
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    • pp.136-141
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    • 2000
  • Concrete has been used for many years as a composite material that has excellent mechanical properties and durability for construction. However, concrete ia a poor electrical conductor, especially under dry conditions. Concrete that is excellent in both mechanical and electrical conductivity properties may have important applications in the electrical, electronic, military and construction industry (e.g for de-icing road from snow). The purpose of this investigation is to improve the electrical conductive of cement mortar preparared with graphite as filler. From the test result, as the ratio of graphite/cement increased, fluidity, fluidity and strength decreased but resistivity decreased. The resistivity of electrical conductive cement mortar is effect by water/cement ratio and water content of specimen. From this study, it is enough to assure the use of graphite as a conductive filler for electrical conducive cement mortar.

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Identification of Electrical Resistance of Fresh State Concrete for Nondestructive Setting Process Monitoring

  • Shin, Sung Woo
    • Journal of the Korean Society for Nondestructive Testing
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    • v.35 no.6
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    • pp.414-420
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    • 2015
  • Concrete undergoes significant phase changes from liquid to solid states as hydration progresses. These phase changes are known as the setting process. A liquid state concrete is electrically conductive because of the presence of water and ions. However, since the conductive elements in the liquid state of concrete are consumed to produce non-conductive hydration products, the electrical conductivity of hydrating concrete decreases during the setting process. Therefore, the electrical properties of hydrating concrete can be used to monitor the setting process of concrete. In this study, a parameter identification method to estimate electrical parameters such as ohmic resistance of concrete is proposed. The effectiveness of the proposed method for monitoring the setting process of concrete is experimentally validated.

Improvement of Seawater Corrosion Resistance of Concrete Reinforcing Steel Using by Conductive Photocatalyst (전도성 광촉매를 이용한 콘크리트 철근의 염해 내구성 향상에 관한 연구)

  • Bae, Geun-Guk;Bae, Geun-Woo;Ahn, Yong-Sik
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.5 no.2
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    • pp.152-159
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    • 2017
  • In marine environment, the durability of concrete and reinforcing steel is known to be deteriorate by the permeation of chloride ion into concrete. In this study the conductive photocatalyst was used to improve the seawater corrosion resistance of the concrete and steel. Mortar and concrete samples were prepared by mixing with various amounts of conductive active carbon and photocatalytic powder($TiO_2$). The compressive strength of concrete was decreased with the increase of the amount of conductive carbon powders. The samples containing conductive carbon and photocatalytic powders showed the superior seawater corrosion resistance compared with the ordinary sample, which was verified by XRF analysis showing the concentration of chloride ion($Cl^-$) of mortars and concretes. The inhibitive effect of photocatalyst against chloride attack was discussed with the diffusion coefficient of chloride ion into mortar and concrete.

Self-Diagnosis Properties of Fracture in Reinforced Concrete Intermixed with Conductive Materials (전도성 재료 혼입 철근콘크리트 구조체의 파괴예측 자기진단 특성)

  • Park, Seok-Kyun;Cho, Sung-Dong
    • Journal of the Korea Concrete Institute
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    • v.20 no.3
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    • pp.369-374
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    • 2008
  • Two types of conductive materials are selected and their applicable properties are investigated so as to give the capability of self-diagnosis of fracture in composite mortar, concrete and reinforced concrete. In this study, for giving selfdiagnosis capability, the powder of cokes and milled carbon fiber as conductive materials are selected and intermixed with mortar, concrete and reinforced concrete. After examining change in the value of electric resistance before and after the occurrence of cracks at each flexural load-stage in composite mortar, concrete or reinforced concrete, the relationships of each factors (electric resistance, crack and flexural load) are analyzed. As the results, it can be recognized that conductive materials with powder of cokes and milled carbon fiber can be applied for self-diagnosis of flexural fracture in composite mortar, concrete and reinforced concrete specimen.

Electrical signal characteristics of conductive asphalt concrete in the process of fatigue cracking

  • Yang, Qun;Li, Xu;Wang, Ping;Zhang, Hong-Wei
    • Smart Structures and Systems
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    • v.14 no.3
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    • pp.469-477
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    • 2014
  • As a kind of intelligent materials, conductive asphalt concrete has a broad application prospect including melting ice and snow on the pavement, closing cracks in asphalt concrete, sensing pavement damage, and so on. Conductive pavement will be suffered from fatigue failure as conventional pavement in the process of service, and this fatigue damage of internal structure can be induced by electrical signal output. The characteristics of electrical signal variation of conductive asphalt concrete in the process of fatigue cracking were researched in this paper. The whole process was clearly divided into three stages according to resistance changes, and the development of fatigue damage wasn't obvious in stage I and stage II, while in stage III, the synchronicity between the resistance and damage began to appear. Thus, fatigue damage variable D and initial damage value $D_0$ represented by the functions of resistance were introduced in stage III. After calculating the initial damage value $D_0$ under different stress levels, it was concluded that the initial damage value $D_0$ had no noticeable change, just ranged between 0.24 and 0.25. This value represented a critical point which could be used to inform the repair time of early fatigue damage in the conductive asphalt pavement.

Effect of Thermal Treatment Temperature on Lifespan of Conductive Oxide Electrode

  • Yoo, Y.R.;Chang, H.Y.;Jang, S.G.;Nam, H.S.;Kim, Y.S.
    • Corrosion Science and Technology
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    • v.6 no.2
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    • pp.44-49
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    • 2007
  • Dimensionally stable anodes have been widely used to cathodically protect the metallic materials in corrosive environments including concrete structure as the insoluble anode. Lifespan of the anode for concrete construction can be determined by NACE TM0294-94 method. Lifespan of conductive oxide electrode would be affected by thermal treatment condition in the process of sol-gel coatings. This work aims to evaluate the effect of thermal treatment temperature on the lifespan of the $RuO_{2}$ electrode. $450^{\circ}C$ treated conductive oxide electrode showed the excellent properties and its lifespan was evaluated to be over 88 years in 3% NaCl, 4% NaOH, and simulated pore water. This behavior was related to the formation of $RuO_{2}$.

Effects of Thermal Conductivities on Temperature History of Massive Concrete Structures (국내 시방서와 ACI 규준 열전달율이 매스콘크리트 온도이력에 미치는 영향)

  • 장동일;손영현;조광현;김광일
    • Journal of the Korean Society of Safety
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    • v.14 no.2
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    • pp.122-126
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    • 1999
  • In this study, using the temperature history analysis, the influences of the conductive values of wooden form, which are specified by Korean Standard for Concrete and ACI Practice Manual for Concrete, on the temperature history were examined. And, the calculated temperature history is compared with the measured temperature history. In the examination for the influences of the conductive values of wooden form, the value recommended by the Korean Standard can more closely predict the themperature history at the points which the variation of the boundary condition should be considered.

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Improvement of Nitrogen Oxide Removal of Concrete Sidewalk Block Using by Conductive Photocatalyst (전도성 광촉매를 이용한 콘크리트 블록의 대기중 질소산화물 저감에 관한 연구)

  • Geun-Guk Bae;In-Sook Cho;Yong-Sik Ahn
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.11 no.4
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    • pp.493-500
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    • 2023
  • The use of TiO2 photocatalyst in the production of concrete blocks for the purpose of nitrogen oxide reduction is an issue of controversy due to the conflicting evidence on its effectiveness. Efforts have been made to reduce the level of nitrogen oxides in the environment by using of titanium dioxide (TiO2). This study examined the effect of incorporating activated carbon into concrete blocks on the reduction of nitrogen oxides released into the atmosphere and the durability of the blocks. The efficiency of photocatalyst was enhanced through the addition of a surrounding conductive substance. The addition of activated carbon resulted in a significant increase in the electrical conductivity of photocatalytic blocks and improved durability. The cement mixture using 5 % TiO2 and 15 % activated carbon exhibited the optimal mixing ratio for the purpose of nitrogen oxide removal. The effect of the addition of conductive carbon to the photocatalytic blocks was discussed with the results of conductivity, flexural and comprssive strength and nitrogen oxide removal test. The relationship between the addition of conductive carbon to the photocatalytic blocks and its resulting effects have been studied by several tests, including conductivity, flexural and compressive strength, and nitrogen oxide removal.