• Title, Summary, Keyword: Strength-to-weight ratio

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The Size of Crowd Pressure According to Loading Patterns (가력유형별 군중하중의 크기에 관한 실험적 연구)

  • Kim, Jin-Sik;Shin, Yun-Ho;Choi, Soo-Kyung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.128-129
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    • 2016
  • This study is to categorize the loading of multiple persons on a vertical building elements into three types to test the size of crowd pressure under each loading patterns. The loading patterns is divided under the combination of loading method and loading persons. The loading method is categorized into the method of instantaneous loading of hand on a force plate and the method of continuous loading. The loading persons has been composed of 1~5 persons under the loading patterns. The loading patterns is also divided into lateral loading, longitudinal loading, and agglomeration loading. The subject group has been composed of 12 males in 20s. The load measurement device(size 1800×600×36mm, capacity 20kN, rigidity 28kN/cm) has been designed and manufactured directly. To eliminate the difference of individual, the size of crowd pressure has been converted into the strength to weight ratio (maximum load/weight) for computation. The strength to weight ratio in lateral loading was about 0.91 under instantaneous loading and about 0.47 under continuous loading. The strength to weight ratio in longitudinal loading was about 0.65 under instantaneous loading and about 0.36 under continuous loading. The strength to weight ratio in agglomeration loading was about 0.65 under instantaneous loading and about 0.36 under continuous loading.

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Properties of High Strength Lightweight Self-Compacting Concrete (고강도 경량 자기충전콘크리트의 성능평가)

  • 최연왕;문대중;안성일;최욱;조선규
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.413-416
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    • 2003
  • Experimental tests on the high strength self-compacting concrete with light-weight fine aggregate and light-weight coarse aggregate(LHSSC) were performed with slump-flow, reaching time to the slump-flow of 500mm, V-funnel dropping time and U-box difference level and compressive strength. LHSCC with light-weight fine aggregate of 75% and light-weight coarse aggregate of 100% was only satisfied with the property conditions of second self-compacting concrete(SCC), like as flowability, resistance to segregation and filling ability. The 28-day compressive strength of LHSCC indicated above 300kgf/$\textrm{cm}^2$ in all concrete mixtures, and it was increased to increase the replacement ratio of light-weight fine aggregate or to decrease the replacement ratio of light-weight coarse aggregate. Therefore, for satisfying the properties of fresh SCC and hardened concrete with above 350kgf/$\textrm{cm}^2$, it would expected that the replacement ratio of light-weight fine aggregate and light-weight coarse aggregate will be determined with 50~75% and 25~50%, respectively.

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The Study on the Physical and Strength Properties of Lightweight Concrete by Replacement Ratio of Artificial Lightweight Aggregate (인공경량골재 혼합비율에 따른 경량 콘크리트의 물성 및 강도특성에 관한 연구)

  • Choi, Se-Jin;Kim, Do-Bin;Lee, Kyung-Su;Kim, Young-Uk
    • Journal of the Korea Institute of Building Construction
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    • v.19 no.4
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    • pp.313-322
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    • 2019
  • This study is to compare and analyze the physical and strength properties of lightweight concrete using domestic lightweight aggregate by replacement ratio of artificial lightweight fine and coarse aggregate after considering low cement mixture and pre-wetting time. The slump, unit weight, compressive strength and split tensile strength of lightweight concrete with domestic lightweight aggregate were measured. As test results, the slump of lightweight concrete by replacement ratio of lightweight fine aggregate increased as the replacement ratio of lightweight fine aggregate increased. The unit weight of lightweight concrete using 100% of lightweight fine aggregate was about 10.4% lower than that of the lightweight concrete with natural sand. In addition, the unit weight of lightweight concrete by replacement ratio of lightweight coarse aggregate increased with the increase of the ratio of LWG10(5~10mm). The compressive strength of lightweight concrete with lightweight fine and coarse aggregate increased as the replacement ratio of lightweight fine aggregate increased. The compressive strength of lightweight concrete with natural sand and LWG10 was 30 to 31MPa regardless of the replacement ratio of the lightweight coarse aggregate after 7 days.

An Experimental Research on the Feature of the Porous Concrete (다공콘크리트의 특성에 관한 실험적 연구)

  • 옥치율;김종주;옥치남
    • Journal of Ocean Engineering and Technology
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    • v.4 no.1
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    • pp.71-80
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    • 1990
  • We experimented the physical property of the porous concrete by changing the water cement ratio, when the aggregate ratios are 1:5 and 1:7 separately. And then we received the results as follows. The bigger, the coarse grading of the porous concrete is, the more sensitive to the water cement ratio, the porous concrete becomes. And if we think over its compressive strength, the coarse aggregate which has 5-15mm width is most appropriate. So we concluded that when its compressive strength, permeability coefficient and its unit weight are $50kg/cm^{2}3cm/sec$ and $1900kg/m^{3}$ respectively, the water cement ratio which has 35-37% width is most appropriate, too. And its compressive strength and unit weight show that they are about a quarter and three quarters respectively about the conventional concrete.

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Light weight vehicle design by stick model (스틱모델에 의한 차체 경량화 설계)

  • 김천욱;김지홍
    • Journal of the korean Society of Automotive Engineers
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    • v.12 no.5
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    • pp.97-106
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    • 1990
  • A method of weight evaluation of the load-bearing structural elements of cars is presented and the weight ratio of the analysis model is investigated. Replacing the materials of floor elements of the car into the high-strength steel, a considerable weight-reduction of the model has been obtained. The 1500cc model is selected for the present study and the stick model analysis is employed for the structural analysis. The torsional stiffness of the weight-reduced model is also evaluated and it is shown it has a reasonable rigidity. The ratio of the weight of the load-bearing structural elements to the unladen vehicle weight of cars is about 0.12for the 1500cc model and the weight-reduction of this study can be obtained around 17% of the weight of the load-bearing structural elements.

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A Study on the Sound Absorption Properties of Sound Absorption Block using by Artificial Light Weight Aggregate (인공경량골재를 이용한 철도 흡음블록의 흡음특성에 관한 연구)

  • Kang, Duck-Man;Seo, Jae-Won;Lee, In-Yong;Park, Yong-Gul
    • Proceedings of the KSR Conference
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    • pp.830-839
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    • 2008
  • This study is designed to manufacture the upgraded sound absorption concrete by using foamed concrete by using artificial light weight aggregate which raises the continuous void ratio to increase the sound absorption ratio and improve the strength. In manufacturing the sound absorption block, the pre-foaming form is applied to generate continuous voids, controlling the density by the addition of bubbles. It is general that the more porosity creates, the weaker strength becomes. Each of specimens are used for this experiment and measured their absorption ratio to examine the absorption property depending on frequency. As a results of experiment, it is evaluated that the absorption capacity of the sound absorption block has relation to compression strength and surface shape.

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An Experimental Study on the Strength Properties of Flowing Lightweight Aggregate Concrete with Age (재령에 따른 고유동 경량골재콘크리트의 강도특성에 관한 실험적 연구)

  • Jeon, Hyun-Kyu;Yoo, Taek-Dong;Seo, Chee-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.2 no.4
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    • pp.186-193
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    • 1998
  • The purpose of this research is to seek properties of flowing light-weight aggregate concrete and possibility of application. The experimental analysis results by using light-weight aggregate and industrial waste such flyash, furnace slag are as follow. 1) The research shows that flowing light-weight aggregate concrete of slump 23~27cm, slump flow 58~69 cm is possible, but material segregation is appeared above slump 26.5cm and slump flow 65 cm. 2) If mixing ratio of flyash is increase, strength deterioration is about 25 % in early age. It showed that effectiveness of long time strength improvement because strength manifestation ratio is above 95% in a long term. 3) This research showed possibility of substitution of blast furnace slag because strength deterioration by using mixing of furnace slag was appeared small deterioration range as below 10 %. 4) Each experimental compressive strength ratios were 77 %(1st week), 86 %(2nd week), 109 %(8th week), 115 %(13th week), 125 % (26th week) on the basis of 28 days. If mixing ratio of flyash is increase, long term strength increase ratio is improved.

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The Study on Compressive-Strength Property of the Aerated Concrete using Glass Fiber by Mixing Ratio (유리섬유 혼입 기포콘크리트의 배합변화에 따른 ,압축강도 특성에 관한 연구)

  • Her Jae-Won;Kim Hyo-Youl;Lim Nam-Gi
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.93-98
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    • 2005
  • The purpose of this study was to analyze the compression strength research by aerated concrete as mixing ratio This Study used foaming-agent and produced aerated concrete by pre-foam way that is used in construction site. An experiment changes unit cement amount, w/c and the glass fiber mixing rate and 'measured capacity change, unit capacity weight and compressive strength. The results obtained from experimental study are as following; Research to reduce unit capacity weight in condition more than unit cement amount 500kgf is considered should be gone side by side. The highest compressive strength result appeared in aerated concrete that cement amount 600kgf and w/c ratio $45\%$, $50\%$. compressive strength was increased maximum $34%$ when glass fiber $0.7\%$ addition cause by coherence enlargement to enlargement of cement paste and glass fiber addition per unit volume

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Properties of Lightweight Foamed Concrete with Incorporating Ratio of Cement Kiln Dust (CKD 치환율 변화에 따른 경량기포 콘크리트의 특성)

  • Shin, Hyun-Sup;Shin, Jae-Kyung;Jeong, Kwang-Bok;Pei, Chang-Chun;Kim, Seong-Soo;Han, Cheon-Goo
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.861-864
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    • 2006
  • This study investigates the properties of light weight foamed concrete with variances in incorporating ratio of cement kiln dust(CKD). Test showed that an increase of CKD incorporating ratio decreased the fluidity of fresh concrete and increased the unit weight. A sinking depth of specimens incorporating CKD decreased, compared with that of control. As for the compressive strength, it firstly increased and then slightly decreased when incorporated CKD. Tensile strength values were similar to the values of compressive strength, but the ratio of comp. to tens. strength increased. Appearances density of specimens were all raged in KS and the thermal conductivity was also satisfied in KS; less than 0.05-0.160W/($m{\cdot}k$).

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Mechanical Characteristics of Reinforced Soil(I) -Cement Reinforced Soil- (보강 혼합토의 역학적 특성(I) -시멘트 혼합토-)

  • Song, Chang-Seob;Lim, Seong-Yoon
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.5 no.6
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    • pp.9-13
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    • 2002
  • This study has been performed to investigate the physical and mechanical characteristics of compaction, volume change and compressive strength for reinforced soil mixed with cement. And confirm the reinforcing effects with admixture such as cement. To this end, a series of compaction test and compression test was conducted for clayey soil(CL) and cement reinforced soil. In order to determine proper moisture content and mixing ratio, pilot test was carried out for soil and cement reinforced soil. And the mixing ratio of cement admixture was fixed 3%, 6%, 9% and 12% by the weight of dry soil. As the experimental results, the maximum dry unit weight(${\gamma}_{dmax}$) was increased with the mixing ratio and then shown the peak at 10% reinforced soil, but the optimum moisture content(OMC) and the volume change was decreased with the ratio increase. And the compressive strength volume change was decreased with mixing ratio increased.