• 제목/요약/키워드: Foam Volume

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Development of lightweight concrete using the PCM II : Investigation on Foam Volume/Fly Ash Relationship of Foam Concrete, and Effect of High Content Micro Polypropylene Fiber and Microstructure

  • Lim, Myung-Kwan;Enkhbold, odontuya;Choi, Dong-Uk
    • KIEAE Journal
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    • 제15권4호
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    • pp.45-52
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    • 2015
  • Purpose: Foam concrete is the concrete that contains large amount of air voids inside. In general, the density of foam concrete depends on parameters like water/binder ratio, foam volume, aggregate and pozzolan content, etc. Method: In this study, the effect of foam volume and fly ash content on dry density is investigated intensively in order to find the relationship between each parameter and their abilities to counteract with each other. According to the above information, though there are quite a number of studies on the effect micro fiber on foam concrete at low volume fractions, there is still lack of information especially on the high fiber content side. The objective of the second study is to investigate further on the use of micro fiber at higher volume fraction and fill in the lacking information. Beside from this study, the investigation of the effect of micro-fiber (polypropylene) to enhance the properties of foam concrete is also carried out. Result: Of the two variables that are investigated in this study, the foam volume and the fly ash content, show significant effect on the properties of foam concrete. The foam volume tends to decrease the density and strength of foam concrete. In the second part of our study, a large fibre volume fraction is proved to be able to evidently increase the flexural strength of foam concrete up to about 40% due to the effect of fibre bridging over the crack and a significant number of fibres that intercepts the crack surfaces. However, the compressive strength is found to decrease severely due to the occurrence of large pores as the result of fibre being added into concrete mixture.

폐스티로폼의 감용방식에 관한 연구 (A Study on the Various Volume Reducing Methods for Wasted EPS Foam)

  • 임중연;최호준;황병복
    • 한국자원리싸이클링학회:학술대회논문집
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    • 한국자원리싸이클링학회 2003년도 추계정기총회 및 국제심포지엄
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    • pp.165-169
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    • 2003
  • Current volume reduction methods for wasted expandable polystyrene (EPS) foam are summarized and compared each other. Wasted EPS foam has not been recycled effectively because of its large volume to weight ratio. This has prevented from its proper recycling because of high cost of transportation to recycling plant. Successful recycling of wasted EPS foam results directly from successful, i.e. economically and environmentally, volume reduction of wasted EPS foam. This paper deals with various methods for volume reduction methods of wasted EPS foam. Five typical methods of volume reduction are introduced and they are compared each other in terms of expected PS properties after volume reduction, cost effectiveness of each process, possible effects on environment caused by the volume reduction process, and possible recycled products. The methods include thermal, solvent, far infrared and mechanical compaction. Comparison in this paper is made mostly in qualitative manner. The focus in this study is concentrated on summarizing and comparing existing methods of volume reduction for wasted EPS foam.

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3D-foam 구조의 구리-주석 합금 도금층을 음극재로 사용한 리튬이온배터리의 전기화학적 특성 평가 (Electrochemical Properties of 3D Cu-Sn Foam as Anode for Rechargeable Lithium-Ion Battery)

  • 정민경;이기백;최진섭
    • 한국표면공학회지
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    • 제51권1호
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    • pp.47-53
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    • 2018
  • Sn-based lithium-ion batteries have low cost and high theoretical specific capacity. However, one of major problem is the capacity fading caused by volume expansion during lithiation/delithiation. In this study, 3-dimensional foam structure of Cu-Sn alloy is prepared by co-electrodeposition including large free space to accommodate the volume expansion of Sn. The Cu-Sn foam structure exhibits highly porous and numerous small grains. The result of EDX mapping and XPS spectrum analysis confirm that Cu-Sn foam consists of $SnO_2$ with a small quantity of CuO. The Cu-Sn foam structure electrode shows high reversible redox peaks in cyclic voltammograms. The galvanostatic cell cycling performances show that Cu-Sn foam electrode has high specific capacity of 687 mAh/g at a current rate of 50 mA/g. Through SEM observation after the charge/discharge processes, the morphology of Cu-Sn foam structure is mostly maintained despite large volume expansion during the repeated lithiation/delithiation reactions.

Effect of waste glass as powder and aggregate on strength and shrinkage of fiber reinforced foam concrete

  • Mayada A. Kareem;Ameer A. Hilal
    • Advances in materials Research
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    • 제12권4호
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    • pp.331-349
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    • 2023
  • Foam concrete can be considered as environmental friendly material due to its low weight, its minimal cost and a possibility to add waste materials in its production. This paper investigates the possibility of producing foam concrete with waste glass as powder and aggregate. Then, the effect of using waste glass on strength and drying shrinkage of foam concrete was examined. Also, the effect of incorporating polypropylene fibers (12 mm length and proportion of 0.5% of a mix volume) on distribution of waste glass as coarse particles within 1200 kg/m3 foam concrete mixes was evaluated. Waste glass was used as powder (20% of cement weight), as coarse particles (25%, 50% and 100% instead of sand volume) and as fine particles (25% instead of sand volume). From the results, the problem of non-uniform distribution of coarse glass particles was successfully solved by adding polypropylene fibers. It was found that using of waste glass as coarse aggregate led to reduce the strength of foam concrete mixes. However, using it with polypropylene fibers in combination helped in increasing the strength by about 29- 50% for compressive and 55- 71% for splitting tensile and reducing the drying shrinkage by about (31- 40%). In general, not only the fibers role but also the uniformly distributed coarse glass particles helped in improving and enhancing the strength and shrinkage of the investigated foam concrete mixes.

바텀애시 경량골재 콘크리트 압축강도에 대한 기포 혼입률 및 양생온도의 영향 (Effect of Foam Volume ratio and Curing Temperature on Compressive Strength of Lightweight using Bottom Ash Aggregates)

  • 이광일;양근혁
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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    • pp.168-169
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    • 2019
  • This study examined the effect of foam volume ratio and curing temperature the air dry density and compressive strength of lightweight concrete using bottom ash. Test results showed that the lightweight concrete possessed the compressive strength of 3.4~22.7 MPa at the air dry density of 1,041~1,583 kg/m3.

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야자계 활성탄을 활용한 폼 복합체의 미세기공 구조특성 (Characteristics of Micro-pore Structure of Foam Composite using Palm-based Activated Carbon)

  • 최영철;유성원
    • 한국구조물진단유지관리공학회 논문집
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    • 제25권5호
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    • pp.157-164
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    • 2021
  • 최근 미세먼지와 관련된 환경문제를 개선하기 위해 유해물질을 제거할 수 있는 광촉매와 흡착제에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 전체 공극량이 일반 건설재료에 비해 상당히 큰 폼 콘크리트에 다량의 마이크로 공극를 갖는 야자계 활성탄소를 이용해서 다공성 폼 복합체를 제작하였다. 미세먼지 흡착 가능성을 평가하기 위해 제작된 폼 복합체에 대해 공극 구조를 분석하였다. 폼 복합체의 공극구조 분석은 측정된 질소 흡착등온선으로부터 BET와 Harkins-jura이론을 적용하였다. 분석결과 활성탄소를 혼입한 폼 복합체의 비표면적과 마이크로 공극 부피가 Plain보다 크게 증가하였다. 활성탄소 혼입율이 증가할수록 폼 복합체의 비표면적과 마이크로 공극 부피가 증가하는 경향을 나타냈다. 이는 폼 복합체가 가스상의 미세먼지 전구물질 NOX에 대한 흡착성능이 높을 것으로 보인다.

바텀애시 골재 기반 경량 콘크리트의 전단마찰거동에 대한 기포 혼입률의 영향 (The effect of Foam Volume Ratio on the Shear Friction Behavior of Bottom Ash Based Lightweight Aggregate Concrete)

  • 김종원;양근혁;문주현
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2020년도 봄 학술논문 발표대회
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    • pp.183-184
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    • 2020
  • This study evaluated the effect of foam volume ratio on shear friction behavior of bottom ash based lightweight aggregate concrete (LWA_BA). The LWA_BA with different foam volume ratio ranged between 8 and 25 MPa for compressive strength(fck), 17.3~62.5 kN for shear capacity at first shear crack(Vcr), 31.1~73.8 kN for shear friction capacity(Vn), and 0.01~0.03 mm for slip at maximum peak load(S0). fck decreased with increase in the foam volume ratio, showing that this trend was also observed in Vcr, Vn, and S0.

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A study on temporal accuracy of OpenFOAM

  • Lee, Sang Bong
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제9권4호
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    • pp.429-438
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    • 2017
  • Cranke-Nicolson scheme in native OpenFOAM source libraries was not able to provide 2nd order temporal accuracy of velocity and pressure since the volume flux of convective nonlinear terms was 1st accurate in time. In the present study the simplest way of getting the volume flux with 2nd order accuracy was proposed by using old fluxes. A possible numerical instability originated from an explicit estimation of volume fluxes could be handled by introducing a weighting factor which was determined by observing the ratio of the finally corrected volume flux to the intermediate volume flux at the previous step. The new calculation of volume fluxes was able to provide temporally accurate velocity and pressure with 2nd order. The improvement of temporal accuracy was validated by performing numerical simulations of 2D Taylor-Green vortex of which an exact solution was known and 2D vortex shedding from a circular cylinder.

Processing of Polyurethane/polystyrene Hybrid Foam and Numerical Simulation

  • Lee, Won Ho;Lee, Seok Won;Kang, Tae Jin;Chung, Kwansoo;Youn, Jae Ryoun
    • Fibers and Polymers
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    • 제3권4호
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    • pp.159-168
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    • 2002
  • Polyurethane foams were produced by using a homogenizer as a mixing equipment. Effects of stirring speed on the foam structure were investigated with SEM observations. Variation of the bubble size, density of the foam, compressive strength, and thermal conductivity were studied. A hybrid foam consisting of polyurethane foam and commercial polystyrene foam is produced. Mechanical and thermal properties of the hybrid foam were compared with those of pure polyurethane foam. Advancement of flow front during mold filling was observed by using a digital camcorder. Four types of mold geometry were used for mold filling experiments. Flow during mold filling was analyzed by using a two-dimensional control volume finite element method. Variation of foam density with respect to time was experimentally measured. Creeping flow, uniform density, uniform conversion, and uniform temperature were assumed for the numerical simulation. It was assumed for the numerical analysis that the cavity has thin planar geometry and the viscosity is constant. The theoretical predictions were compared with the experimental results and showed good agreement.

일축 압축하중 하 다공성 폴리우레탄폼의 재료비선형 거동 및 미세구조 변화 (Material Nonlinear Behavior and Microstructural Transition of Porous Polyurethane Foam under Uniaxial Compressive Loads)

  • 이은선;고태식;이치승
    • 한국재료학회지
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    • 제27권12호
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    • pp.688-694
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    • 2017
  • Porous materials such as polymeric foam are widely adopted in engineering and biomedical fields. Porous materials often exhibit complex nonlinear behaviors and are sensitive to material and environmental factors including cell size and shape, amount of porosity, and temperature, which are influenced by the type of base materials, reinforcements, method of fabrication, etc. Hence, the material characteristics of porous materials such as compressive stress-strain behavior and void volume fraction according to aforementioned factors should be precisely identified. In this study, unconfined uniaxial compressive test for two types of closed-cell structure polyurethane foam, namely, 0.16 and $0.32g/cm^3$ of densities were carried out. In addition, the void volume fraction of three different domains, namely, center, surface and buckling regions under various compressive strains (10 %, 30 %, 50 % and 70 %) were quantitatively observed using Micro 3D Computed Tomography(micro-CT) scanning system. Based on the experimental results, the relationship between compressive strain and void volume fraction with respect to cell size, density and boundary condition were investigated.