• Title/Summary/Keyword: Porous Concrete

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Mechanical Properties of Porous Concrete For Pavement Using Recycled Aggregate and Polymer (재생골재와 폴리머를 이용한 포장용 포러스 콘크리트의 역학적 특성)

  • Park Seung-Bum;Yoon Eui-Sik;Seo Dae-Seuk;Lee Jun
    • Journal of the Korea Concrete Institute
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    • v.17 no.4 s.88
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    • pp.595-602
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    • 2005
  • The purpose of this study is to utilize recycled concrete aggregates as permeable pavement materials. This study evaluates mechanical properties and durability of porous concrete depending on mixing rates of recycled aggregates and polyme. As a result, void ratio and permeability coefficient of porous concrete for pavement increased a little as mixing rate of recycled aggregates increased. Void ratio and permeability coefficient increased a lot as mixing rate of polymer increased. As polymer was mixed $20\%$, national regulation of permeable concrete for pavement($8\%$ and 0.01cm/sec) was met. Compressive strength and flexural strength decreased as mixing rate of recycled aggregates increased but they increased a lot as mixing rate of polymer increased. Even when recycled aggregates were mixed $75\%\;with\;10\%$ polymer mixed, national regulation of pavement concrete(18MPa and 4.5MPa) was met. In addition, regarding sliding resistance, BPN increased as mixing rate of recycled aggregates increased. But BPN decreased as polymer was mixed. Compared to crushed stone aggregates, abrasion resistance and freeze-thaw resistance decreased as mixing rate of recycled aggregates Increased. When polymer was mixed, abrasion resistance and freeze-thaw resistance improved remarkably. Compared to non-mixture, $10\%$ mixture of polymer improved abrasion resistance and freeze-thaw resistance about $8.6\%$ and 3.8times respectively.

Predictions of the maximum plate end stresses of imperfect FRP strengthened RC beams: study and analysis

  • Rabia, Benferhat;Daouadji, Tahar Hassaine;Abderezak, Rabahi
    • Advances in materials Research
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    • v.9 no.4
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    • pp.265-287
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    • 2020
  • A theoretical method to predict the interfacial stresses in the adhesive layer of reinforced concrete beams strengthened with porous FRP plate is presented in this paper. The effect due to porosity is incorporated utilizing a new modified rule of mixture covering the porosity phases. The adherend shear deformations have been included in the present theoretical analyses by assuming a linear shear stress through the thickness of the adherends. Remarkable effect of the porosity has been noted in the results. Indeed, the resulting interfacial stresses concentrations are considerably smaller than those obtained by other models which neglect the porosity effect. It was found that the interfacial stresses are highly concentrated at the end of the FRP plate, the minimization of the latter can be achieved by using porous FRP plate in particular at the end. It is also shown that the interfacial stresses of the RC beam increase with volume fraction of fibers, but decrease with the thickness of the adhesive layer.

The Absorption Characteristics of Foamed Concrete for On-dol (온돌 바닥용 경량기포콘크리트의 흡수특성)

  • 이도헌;전명훈;임정수;정민철;김경덕;민승의
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.05a
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    • pp.225-230
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    • 2001
  • Cast-in-place foamed concrete is a high porous material placed as base the layer of mortar screeds in the panel heating system, so the quality of mortar is affected by it. Therefore, this study is aims to investigate how the absorption characteristics of foamed concrete influences on mortar screeds according to the foamed ratio-62%, 67% and 72%- and the surface treatments of foamed concrete-water and acrylic emulsion primer spray, etc. The result of this study shows that water-spray in the surface of foamed concrete has a good effects to reduce mortar cracking.

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A Review of Porous Media Theory from Woltmans Work to Biots Work

  • Park, Taehyo;Jung, Sochan
    • Journal of the Korean GEO-environmental Society
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    • v.4 no.2
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    • pp.93-104
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    • 2003
  • Porous media consist of physically and chemically different materials and have an extremely complicated behavior due to the different material properties of each of its constituents. In addition, the internal structure of porous materials has generally a complex geometry that makes the description of its mechanical behavior quite complex. Thus, classical continuum mechanics cannot explain the behavior of materials with pore spaces, such as concrete, soils and organic materials in waste landfill. For these reasons, porous media theory has been developed in the nineteenth century. Biot had the greatest influence on the development of porous media theory. Biot's work has been referred by many authors in the literature. Development of numerous fundamental equations in porous media theory were made possible due to Biot's work. His contributions made the greatest influence on porous media theory. Therefore, it is highly advantageous to review Biot's publications. This work presents a review of Biot's work. It shows how porous media theory has been developing so far and provides a chance to discuss the contribution of his work to the modern porous media theory.

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Experimental Study on Recycled-Aggregate Porous Concrete Pile Method (순환골재 다공질 콘크리트말뚝 공법에 대한 실내모형실험)

  • You, Seung-Kyong;Lee, Chang-Min;Kim, Se-Won;Choi, Hang-Seok
    • Journal of the Korean Geosynthetics Society
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    • v.7 no.2
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    • pp.23-29
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    • 2008
  • The purpose of this research is to assess the application of recycled-aggregate that is gained from construction wastes as the material of compaction pile method. At the same time, the development of the new technique rectifies defects of the existing compaction pile method for soft ground improvement. In this research, laboratory chamber tests were carried out analyzing the effect of the soft ground improvement by porous concrete pile using recycled aggregate. Through the results of the laboratory chamber tests, the variations of settlement, excess pore pressure, and increment of the vertical stress with time and the behavior of the composite ground were elucidated.

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Void Ratio, Compressive Strength and Freezing and Thawing Resistance of Natural Jute Fiber Reinforced Non-Sintering Inorganic Binder Porous Concrete (자연마섬유보강 비소성 무기결합재 다공성 콘크리트의 공극률, 압축강도 및 동결융해저항성 평가)

  • Kim, Hwang Hee;Kim, Chun Soo;Jeon, Ji Hong;Park, Chan Gi
    • Journal of The Korean Society of Agricultural Engineers
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    • v.57 no.2
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    • pp.67-73
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    • 2015
  • This study evaluated the effects of fibers on the void ratio, compressive strength and repeated freezing and thawing resistance of porous vegetation concrete with binder type (non-sintering inorganic binder and blast furnace slag cement) and natural jute fiber volume fraction (0.0 %, 0.1 % and 0.2 %). The natural jute fiber volume fraction affected the void ratio, compressive strength and repeated freezing and thawing resistance. Added of natural jute fiber resulted in improved properties of the void ratio, compressive strength and freezing and thawing resistance. Also, the both compressive strength and freezing and thawing resistance increased with natural jute fiber volume fraction up to 0.1 % and then decreased with fiber volume fraction at 0.2 %.

Engineering Properties of Permeable Polymer Concrete for Pavement Using Polypropylene Fiber (폴리프로필렌섬유를 혼입한 포장용 투수성 폴리머 콘크리트의 공학적 성질)

  • Sung, Chan-Yong;Lee, Seung-Hoon
    • Korean Journal of Agricultural Science
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    • v.37 no.2
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    • pp.277-283
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    • 2010
  • Research on permeable pavement like asphalt and concrete pavement with porous structure has been increasing due to environmental and functional need such as reduction of run off and flood. This study was performed to evaluate void ratio, permeability coefficient, and compressive strength of permeable polymer concrete (PPC) using crushed and recycled coarse aggregate that is obtained from waste concrete. Also, 6 mm length of polypropylene fiber was used to increase toughness and interlocking between aggregate and aggregate surrounded by binder. Binder and filler used were unsaturated polyester resin and CaCO3, respectively. The mix proportions were determined to satisfy the requirement for the workability and slump according to aggregate sizes 5~10 mm. In the test results, regardless of kinds of aggregates and fiber contents, the void ratio, permeability coefficient and compressive strength of all types of PPC showed the higher than the criterion of porous concrete that is used in permeable pavement in Korea. Also, strengths of PPC with increase polypropylene fiber volume fraction showed slightly increased tendency due to increase binder with increase of fiber volume fraction. Accordingly, polypropylene fiber and recycled coarse aggregate can be used for permeable pavement.

Mechanical Properties of Permeable Polymer Concrete for Permeability Pavement with Recycled Aggregate and Fiber Volume Fraction (재생골재 및 섬유 혼입률에 따른 포장용 투수성 폴리머 콘크리트의 역학적 특성)

  • Sung, Chan-Yong;Kim, Young-Ik
    • Journal of The Korean Society of Agricultural Engineers
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    • v.52 no.1
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    • pp.69-77
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    • 2010
  • Research on permeable pavement like asphalt and concrete pavement with porous structure has been increasing due to environmental and functional need such as reduction of run off and flood, and increase and purification of underwater resource. This study was performed to evaluate permeability, strengths and durability of permeable polymer concrete (PPC) using recycled aggregate that is obtained from waste concrete. Also, 6mm length of polypropylene fiber was used to increase toughness and interlocking between aggregate and aggregate surrounded by binder. In the test results, regardless of kinds of aggregates and fiber contents, the compressive strength and permeability coefficient of all types of PPC showed the higher than the criterion of porous concrete that is used in permeable pavement in Korea. Also, strengths of PPC with increase polypropylene fiber volume fraction showed slightly increased tendency due to increase binder with increase of fiber volume fraction. The weight reduction ratios for PPC after 300 cycles of freezing and thawing were in the range of 1.6~3.8 % and 2.2~5.6 %, respectively. The weight change ratio was very low regardless of the fiber volume fraction and aggregates. The weight reduction ratios of PPC with fiber and aggregate were in the range of 1.3~2.7 % and 2.2~3.2 % after 13 weeks and was very low regardless of the fiber volume fraction and aggregates.

Shear Strength Characteristics of Recycled-Aggregate Porous Concrete Pile for Soft Ground Improvement (순환골재를 활용한 연약지반개량용 다공질 콘크리트 말뚝의 전단특성)

  • Yoon, Gil-Lim;Yoon, Yeo-Won;Kang, O-Ram;You, Seung-Kyong;Lee, Kyu-Hwan
    • Journal of the Korean Geotechnical Society
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    • v.24 no.12
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    • pp.75-84
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    • 2008
  • Recycled-aggregate porous concrete pile (RAPP) which forms a composite ground is one of new ground improvement techniques. In this paper, triaxial compression tests are carried out to investigate the shear strength characteristics of RAPP-Clay composite samples. The main purpose of the tests was to investigate the effects of area replacement ratio ($15%{\sim}100%$) on behaviors of RAPP-Clay samples during shearing. Also, triaxial compression tests using Sand-Clay composite samples were performed to compare with the behaviors of RAPP-Clay samples. The test results showed that the friction angle and cohesion of the RAPP-Clay composite were $18{\sim}34$ degree and $557.0{\sim}588.0\;kPa$, respectively, whereas those of sand-clay composite samples were 26~35 degree of friction angel and $4.0{\sim}18.0\;kPa$.

An Experimental Study on Permeability in Elevation of Porous Concrete Using Unsaturated Polyester Resin (불포화 폴리에스터수지를 이용한 투수 콘크리트의 투수성 향상에 관한 실험적 연구)

  • Lho, Byeong-Cheol;Choi, Kyu-Hyung;Kim, Jeong-Hoon
    • Journal of the Korea Concrete Institute
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    • v.19 no.2
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    • pp.163-169
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    • 2007
  • This study is focused on the proper mixture design of materials for the porous concrete with unsaturated polyester resin. The materials used in the mixture include the single-grade aggregates, unsaturated polyester resin as binder, and calcium carbonate as a filler. An experimental procedure has been carried out to select the best combination of the materials that satisfy both the required permeability and compressive strength. Various kinds of gravel size, the ratio of binder, and F/B ratios are tried to get proper mixture, and the permeability coefficient and compressive strength have been measured to find out the best combination of materials based on the proper Korean Standards. A promix design satisfied the standards of rainfall runoff reduction system with $3.5{\times}10^{-1}$ (cm/sec) of permeability, 34 % of porosity, 11 MPa of compressive strength can be obtained.