• Title, Summary, Keyword: Porous ratio

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Mechanical Characteristics of Porous Concrete using Recycled-Aggregate (순환골재를 이용한 투수성 콘크리트의 역학특성)

  • You, Seung-Kyong;Yu, Nam-Jae;Cho, Sung-Min;Shim, Min-Bo
    • Journal of the Korean Geosynthetics Society
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    • v.6 no.2
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    • pp.17-20
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    • 2007
  • In this study, a series of uniaxial unconfined compression test and constant-head test were performed to investigate the mechanical characteristics of porous concrete using recycled-aggregate for the varying unit weight and water-cement ratio. To enhance the permeability of the porous concrete, the recycled-aggregate with similar grain size in the range of $40{\pm}5mm$ was used and water-cement ratio that leads to the lean-mix was adapted. The mechanical characteristics of the porous concrete cured for 3 days were examined; the compressive strength and $E_{50}$ showed their maximum values with 40% water-cement ratio and $1.8t/m^3$ unit weight and the permeability coefficient was averagely measured in the range of $0.9{\times}10^0cm/sec$ regardless of water-cement ratio and unit weight.

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Physical and Mechanical Properties of Non-Cement Porous Concrete with Alkali-Activator Contents (알칼리활성화제 치환율에 따른 무시멘트 다공성 콘크리트의 물리·역학적 특성)

  • Kim, Dong-Hyun;Kim, Chun-Soo;Park, Chan Gi
    • Journal of The Korean Society of Agricultural Engineers
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    • v.55 no.2
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    • pp.59-64
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    • 2013
  • The present study is to evaluate physical and mechanical properties of porous concrete having non cement that mainly causes carbon emission. This study aims to explore eco-friendly concrete technology capable of reducing the amount of carbon emission due to the use of normal cement by substituting it with non cement porous concrete to which alkali-activator and blast-furnace slag powder are impregnated. As experimental variables, 5 %, 6 %, 7 %, 8 %, 9 % and 10 % of alkali-activator were substituted as binders and applied. Testing evaluated in this study were pH value, void ratio, compressive strength and residual compressive strength shown after being immersed in $H_2SO_4$ solution and $Na_2SO_4$ solution. The test results were compared with those tested with the use of porous concrete to which 400 $kg/m^3$ of unit cement amount was applied as binder. In consequence, it was concluded that; as for pH value, it was decreased than was the case in which cement was used, but increased with the more the use of alkali activator; as for void ratio and compressive strength, the mix proportion in which 9 % and 10 % of alkali activator were applied in terms of substitution ratio showed the result similar to the mixture in which 400 $kg/m^3$ of unit cement ratio was applied; and, as for residual compressive strength in the case of being immersed in $H_2SO_4$ solution and $Na_2SO_4$ solution, the compressive strength was increased, thus leading to improved chemical resistance.

Effect of Aluminum Addition on Porosity and Flexural Strength of Porous Self-Bonded Silicon Carbide Ceramics (알루미늄 첨가가 다공질 Self-Bonded SiC 세라믹스의 기공률과 꺾임강도에 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.46 no.5
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    • pp.520-524
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    • 2009
  • Porous self-bonded silicon carbide (SBSC) ceramics were fabricated at temperatures ranging from 1750 to $1850^{\circ}C$ using SiC, Si, C as starting materials and Al as an optional sintering additive. The effect of Al addition on the porosity and strength of the porous SBSC ceramics were investigated as functions of sintering temperature and Si:C ratio. The porosity increased with decreasing the Si:C ratio and increasing the sintering temperature. It was possible to fabricate SBSC ceramics with porosities ranging from 37% to 44% by adjusting the Si:C ratio and the sintering temperature. Addition of Al additive promoted densification and necking between SiC grains, resulting in improved strength. Typical flexural strengths of SBSC ceramics with and without Al addition were 44 MPa and 34MPa, respectively.

Static analysis of non-uniform heterogeneous circular plate with porous material resting on a gradient hybrid foundation involving friction force

  • Rad, A. Behravan;Farzan-Rad, M.R.;Majd, K. Mohammadi
    • Structural Engineering and Mechanics
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    • v.64 no.5
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    • pp.591-610
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    • 2017
  • This paper is concerned with the static analysis of variable thickness of two directional functionally graded porous materials (FGPM) circular plate resting on a gradient hybrid foundation (Horvath-Colasanti type) with friction force and subjected to compound mechanical loads (e.g., transverse, in-plane shear traction and concentrated force at the center of the plate).The governing state equations are derived in terms of displacements based on the 3D theory of elasticity, assuming the elastic coefficients of the plate material except the Poisson's ratio varying continuously throughout the thickness and radial directions according to an exponential function. These equations are solved semi-analytically by employing the state space method (SSM) and one-dimensional differential quadrature (DQ) rule to obtain the displacements and stress components of the FGPM plate. The effect of concentrated force at the center of the plate is approximated with the shear force, uniformly distributed over the inner boundary of a FGPM annular plate. In addition to verification study and convergence analysis, numerical results are displayed to show the effect of material heterogeneity indices, foundation stiffness coefficients, foundation gradient indices, loads ratio, thickness to radius ratio, compressibility, porosity and friction coefficient of the foundation on the static behavior of the plate. Finally, the responses of FG and FG porous material circular plates to compound mechanical loads are compared.

Preparation of Porous PLGA Microfibers Using Gelatin Porogen Based on a Glass Capillary Device (젤라틴 기공유도물질과 유리모세관 장치를 이용한 다공성 PLGA 미세섬유의 제조)

  • Kim, Chul Min;Kim, Gyu Man
    • Journal of the Korean Society for Precision Engineering
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    • v.33 no.1
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    • pp.63-67
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    • 2016
  • We present a method of fabricating poly (lactic-co-glycolic acid) (PLGA) porous microfibers using a pore template. PLGA microfibers were synthesized using a glass capillary tube in a poly-(dimethylsiloxane) (PDMS) microfluidic chip. Gelatin solution was used as a porous template to prepare pores in microfibers. Two phases of PLGA solutions in different solvents-DMSO (dimethyl sulfoxide) and DCM (dichloromethane)-were used to control the porosity and strength of the porous microfibers. The porosity of the PLGA microfibers differed depending on the ratio of flow rates in the two phases. The porous structure was formed in a spiral shape on the microfiber. The porous structure of the microfiber is expected to improve transfer of oxygen and nutrients, which is important for cell viability in tissue engineering.

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 %.

Evaluation of Load Capacity and Toughness of Porous Concrete Blocks Reinforced with GFRP Bars (GFRP 보강 다공성 콘크리트 블록의 내력 및 인성 평가)

  • Jung, Seung-Bae;Yang, Keun-Hyeok
    • Journal of the Korea Institute of Building Construction
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    • v.17 no.5
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    • pp.403-409
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    • 2017
  • In this study, mix proportioning of porous concrete with compressive strength and porosity exceeding 3MPa and 30%, respectively, was examined and then load capacity and flexural toughness of the porous concrete block were evaluated according to the different arrangements of the GFRP bars. To achieve the designed requirements of porous concrete, it can be recommended that water-to-cement ratio and cement-to-coarse aggregate ratio are 25% and 20%, respectively, under the aggregate particle distribution of 15~20mm. The failure mode of porous concrete blocks reinforced with GFRP bars was governed by shear cracks. As a result, very few flexural resistance of the GFRP was expected. However, the enhanced shear strength of porous concrete due to the dowel action of the GFRP bars increased the load capacity and toughness of the blocks. The porous concrete blocks reinforced with one GFRP bar at each compressive and tensile regions had 2.1 times higher load capacity than the companion non-reinforced block and exhibited a high ductile behavior with the ultimate toughness index ($I_{30}$) of 43.4.

Microstructure and Physical Properties of Porous Material Fabricated from a Glass Abrasive Sludge (유리연마슬러지를 사용한 다공성 소재의 미세구조 및 물리적 특성에 관한 연구)

  • Chu, Yong-Sik;Kwon, Choon-Woo;Lee, Jong-Kyu;Shim, Kwang-Bo
    • Journal of the Korean Ceramic Society
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    • v.43 no.5
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    • pp.277-283
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    • 2006
  • A porous material with a surface layer was fabricated from glass abrasive sludge and expanding agents. The glass abrasive sludges were mixed with expanding agents and compacted into precursors. These precursors were sintered in the range of $700-900^{\circ}C$ for 20 min. The sintered porous materials had a surface layer with smaller pores and inner parts with larger pores. The surface layer and closed pores controlled water absorption. As the expanding agent fraction and the sintering temperature increased, the porosity and pore size increased. The porous materials with $Fe_2O_3$ and graphite as the expanding agents had a low absorption ratio of about 3% or lower while the porous material with $CaCO_3$ as the expanding agent had a higher absorption ratio and more open pores.

Planting Properties of Porous Polymer Block Using Recycled Coarse Aggregates (재생굵은골재를 사용한 다공성 폴리머 블록의 식생 특성)

  • Sung, Chan-Yong;Kim, Young-Ik
    • Korean Journal of Agricultural Science
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    • v.37 no.1
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    • pp.87-96
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    • 2010
  • This study was performed to evaluate the planting properties of herbaceous plant and cool-season grass in porous polymer blocks that were manufactured by using recycled coarse aggregates and unsaturated polyester resin to develop environmentally friendly planting blocks. Unsaturated polyester resin, natural and recycled coarse aggregates and $CaCO_3$ were used. The mix proportions were determined to satisfy the requirement for the workability and slump according to aggregate sizes(5-10 and 5-20mm). Tests for the void ratio and compressive strength of porous polymer concrete were performed at curing age 7 days. Also, porous polymer block using recycled coarse aggregates were applied to kinds of plants such as tall fescue, Perennial ryegrass, Lesedeza and Alfalfa. After seed, initial germination, germination ratio, cover view and growth length for planting blocks were estimated by various methods.

An Experimental Study on the Application of Porous Scoria Concrete to Artificial Reefs for Soft Coral (연산호 육성용 어초 개발을 위한 송이 다공성 콘크리트의 적용성에 관한 실험적 연구)

  • HONG CHONG-HYUN;KIM MOON-HOON;KIM SEOK-CHEL;PARK SUNG-BAE;Ryu SEONG-PIL
    • Journal of Ocean Engineering and Technology
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    • v.19 no.4
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    • pp.28-34
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    • 2005
  • In the study application of volcanic scoria concrete to artificial reefs is investigated. Volcanic scoria is a natural volcanic product that shows light weight, mil/i-porous, and far-infrared irradiation characteristics. The properties of volcanic scoria concrete using Jeju scoria aggregate are evaluated by conducting a comprehensive series of tests on strength and void ratio. It is concluded that the volcanic scoria concrete has the sufficient strength of 4MPa-13MPa and adequate void ratio of $12\%-35\%$ to be accepted as artificial reef concrete. The field experiments are performed through observation by scuba diver's at the Seogwipo coast. Porous specimen and plane concrete specimen are prepared for comparison purposes. Seasonal changes of soft coral on the two series of test specimens were have been observed from Apr. 9, 2004 to Mar. 18, 2005. The soft coral is well grown on the porous specimen however there are no significant changes on the conventional plain concrete specimen. Thus it is concluded that the volcanic scoria concrete is highly suitable as artificial reef concrete.