• Title, Summary, Keyword: Porous ratio

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Physical·Mechanical and Temperature Properties of Fiber Reinforced Porous Green Roof Hwang-toh Concrete (섬유보강 다공성 옥상녹화 황토콘크리트의 물리·역학적 및 온도변화 특성 평가)

  • Oh, Ri On;Kim, Chun Soo;Kim, Hwang Hee;Jeon, Ji Hong;Kwon, Wan Sig;Park, Chan Gi
    • Journal of The Korean Society of Agricultural Engineers
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    • v.55 no.4
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    • pp.65-72
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    • 2013
  • The physical, mechanical, water purification and temperature properties of fiber reinforced porous hwang-toh green roof concrete have been evaluated in this study. The effect of the depending on replacement ratio of blast furnace slag to cement was investigated such that the replacement ratio is varied to 0 % and 30 %. Also, the replacement ratios of hwang-toh were 0, 20 and 30 %. The polyvinyl alcohol fiber was used for the reinforcing fiber. A series of pH test, unit weight, void ratio, compressive strength, after purification and variation of temperature test have been performed to evaluate the performance, water purification effect and temperature properties of the fiber reinforced porous hwang-toh green roof concrete. The test results indicate that the physical and mechanical properties of fiber reinforced porous hwang-toh green roof concrete is affected by the replacement ratio of the blast furnace slag and hwang-toh contents. Results of purifying water showed that the water purification effect of porous hwang-toh green roof concrete is about 40 %. Also, the temperature properties test results indicate the green roof blocks using fiber reinforced porous hwang-toh green roof concrete have insulation and temperature reduction effect.

An Expermental Study on the Properties of Porous Concrete Pavement (투수성 콘크리트 포장의 특성에 대한 실험적 연구)

  • 문한영;김성수;김홍삼;정호섭
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.329-334
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    • 1997
  • Most of domestic pavement were non-permeable. However, in foreign country although it wasn't entirely satisfied, porous pavement was partially utilized with footpaths and soft-roadways. In this study, experiments were carried out to investigate the properties fundamental of porous concrete pavement. As a result of experiments, it was concluded that the coefficient of permeability was increased in proportion to continuous void ratio and decreased in proportion to S/a ratio and unit cement contents. On the other hand, the strength of porous concrete pavement was in inverse proportion to the void ratio.

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A Yield Function for Sintered Porous Metals (소결분말금속의 항복함수)

  • 박종진
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.5
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    • pp.1115-1122
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    • 1993
  • Several yield criteria for porous materials are compared with each other, defining the apparent yield stress as the yield stress of the porous material in simple compression. It was found that the plastic Poisson's ratio is the parameter needed to define the yield criterion, rather than the relative density. The plastic Poisson's ratio is regarded as a material characteristic that is obtained from a simple compression test. A new form of yield criterion was suggested, and it was applied to hydrostatic compression as well as uniaxial strain compression of sintered Al-2024 powder. The crossover point in the mean stress vs volume change curves of the processes was predicted. It is presented that the flow stress of the fully densed material can be obtained from that of the porous material using relations obtained from the yield criterion.

An Experimental Study on the Mechanical Properties of Porous Concrete Using Coal Ash and Polymer (석회석 골재를 사용한 강섬유보강 포러스콘크리트의 강도특성에 관한 실험적 연구)

  • Lee, Byung-Jae;Park, Seong-Bum;Jang, Young-Il;Jeon, Heum-Jin;Lee, Taek-Woo
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.685-688
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    • 2008
  • Concrete is strong on the compressive property, but weak on the tensile and flexural properties. To improve these problems, the reinforcing bar is used in concrete. But porous concrete with steel fiber has a weak point when exposed to air, because porous concrete has the vast continuous void on its inside and steel fiber is easily rusted by air. For these reasons, this study investigated the void ratio, compressive strength, bending strength and bending toughness as steel fiber mixing ratio and target void ratio. From test results, actual void ratio and strength properties increased as the mixing ratio of steel fiber increase. In case the mixing ratio of steel fiber over the fixed ratio, strength is decreased. And from the toughness evaluation, compared to the porous concrete which isn't mixed with steel fiber, the deflection variation efficiency is remarkably improved. Consequently we can confirm the possibility of porous concrete with steel fiber for the secondary product and pavement material to improve strength and bending resistance efficiency.

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The Study on Sound Absorbing Characteristics of Porous Concrete according to Reverberation Room Methods (랜덤입사방법에 의한 포러스 콘크리트의 흡음특성에 관한 실험적 연구)

  • Seo Dae seuk;Park Seong Bum;Cho Gwang yeon;Jang Young Ill;Kim Hyung Seok;Lee yoon Sun
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.568-571
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    • 2004
  • This research estimated the physical. mechanical characteristic and the character of sound absorption according to target void ratio of porous concrete and the mixing ratio of recycled aggregate for the valid utilization of recycled aggregate using waste concrete and sound reduction out of a road, a railway, a residential street, and a downtown area. As a result of the test, compressive strength tended to be a radical strength fall when target void ratio was $25\%$ and contents of recycled aggregate exceeded over $50\%$. Also, the character of sound absorption of porous concrete which used recycled aggregate using waste concrete was the most excellent when target void ratio was $25\%$, and the influence by contents of recycled aggregate was trivial. Therefore, when the strength and the character of sound absorption of porous concrete are considered, it is proved valid that proper target void ratio was $25\%$ and contents of recycled aggregate using waste concrete was $50\%$ or so.

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Effect of Si:C Ratio on Porosity and Flexural Strength of Porous Self-Bonded Silicon Carbide Ceramics (Si:C Ratio가 다공질 Self-Bonded SiC 세라믹스의 기공율과 곡강도에 미치는 영향)

  • Lim, Kwang-Young;Kim, Young-Wook;Woo, Sang-Kuk;Han, In-Sub
    • Journal of the Korean Ceramic Society
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    • v.45 no.5
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    • pp.285-289
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    • 2008
  • Porous self-bonded silicon carbide (SiC) ceramics were fabricated at temperatures ranging from 1750 to $1850^{\circ}C$ using SiC, silicon (Si), and carbon (C) powders as starting materials. The effect of the Si:C ratio on porosity and strength was investigated as a function of sintering temperature. It was possible to produce self-bonded SiC ceramics with porosities ranging from 36% to 43%. The porous ceramics showed a maximal porosity when the Si:C ratio was 2:1 regardless of the sintering temperature. In contrast, the maximum strength was obtained when the ratio was 5:1.

Study on the Properties of Porous Concrete According to the Aggregate Shape and Size (골재 입형 및 크기에 따른 포러스 콘크리트의 특성에 관한 연구)

  • Lim, Seo-Hyung;Kang, Hyun-Sik;Jee, Nam-Yong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.9 no.3
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    • pp.93-100
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    • 2005
  • The purpose of this study is to investigate the physical properties of porous concrete according to the aggregate shape and size which is produced by con crusher and impact crusher. For this purpose, the selected test variables were the aggregate size and shape, the ratio of water to cement and the ratio of paste to aggregate. The results of this study showed that its economic performance and physical properties were improved using the aggregate made by impact crusher. The coefficient of permeability and compressive strength of porous concrete had a close correlationship with the void ratio, and it was suggested as a function of void ratio.

Fabrication of Porous Material Using Glass Abrasive Sludge

  • Chu, Yong-Sik;Kwon, Chun-Woo;Lee, Jong-Kyu;Shim, Kwang-Bo
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • pp.606-607
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    • 2006
  • A porous material with a surface layer was fabricated using glass abrasive sludge and expanding agents. The glass abrasive sludges were mixed with expanding agents and compacted into pellets. These pellets were sintered in the range of $700-900^{\circ}C$ for 20min. The sintered porous materials had a surface layer with smaller pores and inner parts with larger pores. The surface layer and pores controlled the absorption ratio and physical properties.

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Physical and Mechanical Properties of Porous Concrete Using Waste Activated Carbon (폐활성탄을 사용한 다공성 콘크리트의 물리.역학적 성질)

  • Youn, Joon-No;Sung, Chan-Yong;Kim, Young-Ik
    • Journal of The Korean Society of Agricultural Engineers
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    • v.51 no.4
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    • pp.21-27
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    • 2009
  • This study was performed to evaluate the physical and mechanical properties of porous concrete using waste activated carbon. Material used were ordinary portland cement, recycled coarse aggregate, waste activated carbon and superplasticizer. The replacement ratios of waste activated carbon were 0,1,2,3,4,5,6,7,8,9, and 10 %. The void ratio was decreased and ultrasonic pulse velocity was increased with increasing the waste activated carbon powder, respectively. The compressive strength and flexural strength of porous concrete using waste activated carbon powder were in the range of 8.21${\sim1}$6.58 MPa and 1.69${\sim1}$3.68 MPa, respectively. The pH degree of porous concrete in 1day and 77days were shown in 12.50${\sim1}$12.63 and 10.21${\sim1}$10.70, respectively. Accordingly, waste activated carbon can be used for porous concrete material.

The Mechanical Properties of Porous Concrete using Recycled Asphalt Aggregate (아스팔트순환골재를 이용한 투수성 콘크리트의 역학적 특성)

  • Lee, Dong-Wook;Yun, Jung-Mann;Kim, Nam-Sik;Kang, Young-Min
    • Journal of the Korean Geosynthetics Society
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    • v.10 no.1
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    • pp.37-42
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    • 2011
  • In this study, it is analyzed that mechanical properties and required strength of porous concrete according to the mixing ratio of cement, fine aggregate, and water/cement ratio in order to evaluate mechanical properties of porous concrete using recycled asphalt aggregate. Recycled asphalt aggregates of 13 mm were used without modification of aggregate grading to extend porous concrete application. The water/concrete ratio was poor mix and the range of compressive strength was 18.2 to 19.5 MPa. The average value of permeability showed 8.0E-02 cm/sec.