• Title/Summary/Keyword: Crushed sand ratio

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A Study on the Characteristics of Concrete Use Crushed Aggregates Produced in Busan Suburbs (부산근교에서 생산된 부순골재를 사용한 콘크리트의 특성에 관한 연구)

  • Bae Won Mahn;Beak Dong Il;Jang Hui suk;Kim Myung Sik
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.193-196
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    • 2004
  • The objective of in this study makes investigation into the characteristics of concrete as to properties and blended ratio of crushed aggregates through experimental researches. In this research observed crushed quality characteristic of crushed aggregates that is produced in representative stony mountains of Busan suburbs (Yang-san, Kim-hea, Jin-hea). And wished to investigate the quality change and characteristics of concrete with variation of blend ratio of crushed sand(50, 60, 70, 80, 90, $100\%$). Measured the air contents and slump to investigate properties of fresh concrete, and unit weight and compressive strength in age of 7, 28, 60, 90 days to investigate properties of hardened concrete.

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The Effect of W/C Ratio and Chloride on Compressive Strength of Concrete Exposed to High-temperature (물-시멘트비 및 염화물이 고온에 노출된 콘크리트의 압축강도에 미치는 영향)

  • 태순호;이병곤
    • Journal of the Korean Society of Safety
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    • v.14 no.1
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    • pp.124-128
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    • 1999
  • Product background of cement, sand and coarse aggregate differ from country to country, so that thermal behaviour of concrete make a difference in high temperature. To cope with demand, this paper is a study on compressive strength for W/C 45%, 55% and 65% by using domestic portland cement, Han-river sand, sea sand and crushed-coarse aggregate. As a result, it is shown that it is estimating to the mechanical properties of heated concrete specimens under various W/C ratio.

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A Study on Practicalization Plan of Concrete Using Crushed Sand (부순모래의 실용화 방안에 관한 연구)

  • Lee, Y. H.
    • Journal of Korean Port Research
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    • v.9 no.1
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    • pp.65-72
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    • 1995
  • This study is being done for the purpose to achieve a stable demand and supply of materials for long term. The author investigated condition of suitable mixer design method for concrete, an individual value and a character of dynamics as a supplement material by drying up the natural aggregate, and a possible practicalization plan to reduce defects to the minimum. As a result of this study, it can be acquired a good quality of concrete by the use of the natural sand (Nak Dong river sand) and the crushed sand with suitable mixing ratio. The fineness modulus (F.M) of mixing aggregate is $2.7\pm1$ at this time and this is good for workbility and plasticity of concrete.

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A Study on the Properties of Crushed Aggregate for Concrete produced in Korea (국내 콘크리트용 부순골재의 품질특성에 관한 연구)

  • 최세진;정용;오복진;김무한
    • Proceedings of the Korea Concrete Institute Conference
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    • 2003.11a
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    • pp.112-115
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    • 2003
  • Aggregate may limit the strength of concrete, and aggregate with undesirable properties cannot produces strong concrete. Also, the properties of aggregate greatly affect the durability and structural performance of concrete. Recently, it has increased the using of crushed aggregate for concrete due to the exhaustion of good natural aggregate. In case of Korea, in 2002, the using ration of crushed stone occupies about 97% of whole coarse aggregate, and ratio of crushed sand occupies about 18.3% of whole fine aggregate. This is a study to compare and analyze the properties of crushed aggregate for concrete to do mix proportion and improve the concrete quality. According to results, it was found that nearly all the properties of crushed aggregate satisfied with the value recommended by KS.

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A Model Test Study on the Bearing Capacity of the Crushed Stone Pile (쇄석말뚝의 지지력 특성에 관한 모형시험 연구)

  • 이상익;박용원;김병일;윤길림
    • Proceedings of the Korean Geotechical Society Conference
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    • 2001.03a
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    • pp.299-306
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    • 2001
  • Crushed Stone Pile(CSP) is one of the ground improvement methods available to loose sand and clayey ground by forming compacted CSP in the weak soil layer. The effects of this method are enhancement of ground bearing capacity, reduction of settlement and prevention of lateral ground movement in cohesive layer, reduction of liquefaction potential in sandy ground. This study performs model tests in 1.0m${\times}$1.0m${\times}$1.0m and 1.5m${\times}$1.5m${\times}$l.2m model tank to observe bearing capacity of CSP treated ground. The area replacement ratio of CSP composite ground varies 20%, 30% and 40% with square grid pattern. After the composite ground was consolidated under pressure of 0.5kg/$\textrm{cm}^2$ and 1.0kg/$\textrm{cm}^2$, load tests were carried out. The results show that ultimate bearing capacity increases with area replacement ratio and the preconsolidation pressure of ground.

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A Study on the Influnence of the Properties of Concrete on Powder Content and Shape of Crushed Sand (부순모래의 미립분 함유량 및 입형이 콘크리트의 특성에 미치는 영향에 관한 연구)

  • 이진규;윤기원;임종민;이종태;김성식;한천구
    • Proceedings of the Korea Concrete Institute Conference
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    • 1996.10a
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    • pp.17-23
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    • 1996
  • The objective of this study is to present the reference data about the influence of concrete properties using crushed sand, according to the change of powder content and grain shape. From the test results. We obtained that as powder content is increased, sand aggregate ratio, water content and S.P/C are increased in mixing design of concrete. The more powder content is the less slump and air content loss are decreased in fresh state, but the higher compressive strength and drying shrinkage are increased in hardened concrete state. As grain shape become round, water content is decreased in mixing design of concrete. And also, loss of slump and air content in fresh state, compressive strength in hardened state are increased.

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Spalling Characteristics of High Performance Concrete According to Changes in PP Fiber Ratio and Type of Aggregate (PP섬유 혼입율 및 잔골재 종류 변화에 따른 고성능 콘크리트의 폭렬특성)

  • Jung, Hong-Keun;Kim, Won-Ki;Pei, Chang-Chun;Han, Min-Cheol;Yang, Seng-Hwan;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2009.05b
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    • pp.61-64
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    • 2009
  • This study is reviewed fire resistance characteristics of high strength concrete according to changes in PP fiber mixing ratio and type of fine aggregate, and the results can be summarized as follows. As fire resistance characteristics, all plain crushed sands prevented spalling regardless of increase in mixing ratio of PP fiber. Mixtures other than the plain showed satisfactory spalling prevention when 0.05 % or more of PP fiber was mixed. After the fire resistance experiment, the plain showed 5.5 % of mass loss rate when fiber was not mixed and others could not be measured. According to increase in mixing ratio of fiber, river sand with fineness modulus of 2.2 showed most satisfactory result of 34 %${\sim}$42 %. Mass loss rate after fire resistance experiment was most satisfactory at about 10 % in the plain crushed sand without mixing of fiber, and all other mixes with 0.05 % PP fiber or more showed 5${\sim}$10 % loss rate.

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An Experimental Study on the Effects of Crushed Stone Compaction Pile in the Sea Clay Layer (해성 점토지반의 쇄석다짐말뚝 보강 효과에 관한 실험적 연구)

  • Lee, Seung-Bong;Im, Jong-Chul;Park, Lee-Keun;Joo, In-Gon
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.1031-1038
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    • 2005
  • Recently, due to lack of sand suppy, the cost of sand has increase. Therefore, alternative materials are needed. So, in this study the Crush Stone Compaction Pile used in America and Europe has been compared and analyzed Sand Compaction Pile used in Korea. Tests were performed at various sizes of Crush Stone and replacement ratio. Frist, it was compared and analyzed with low and high replacement ratio with the same size of crush stone. Second, it was compared and analyzed with different size of crush stone at constant replacement ratio. The result of these tests were compared with sand of the same replacement ratio. Here, the properties that were comares and analyzed are the ultimate bearing capacity and quantity of ground upheaval.

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A Study on Properties of Concrete Made of Natural and Crushed Sand in High Temperatures (자연모래와 부순모래를 사용한 콘크리트의 고온 하에서 특성연구)

  • Kim, Joo-Seok;Choi, Yeol
    • Journal of the Korea Concrete Institute
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    • v.24 no.1
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    • pp.53-60
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    • 2012
  • The main object of this paper is to investigate the effects of high temperatures on the physical and mechanical properties of natural sand concrete(NSC) and crushed sand concrete(CSC). Test samples were exposed to high temperature ranging from $200^{\circ}C$ to $800^{\circ}C$. After exposure, various tests were conducted. Color image analysis and weight losses were determined and compressive strength test and splitting tensile strength test were conducted. The results indicated that weight losses increased as exposure temperature increased with comparable decreasing rate. The results also showed that compressive strength and splitting tensile strength and modulus of elasticity decreased as exposure temperature increased. The results also showed that residual compressive strength of NSC decreased more drastically than that of CSC at $200^{\circ}C$ and $400^{\circ}C$. Residual splitting tensile strength of NSC decreased more than that of CSC at $200^{\circ}C$, while NSC and CSC showed comparable residual strength ratio at $800^{\circ}C$.

Chloride Diffusion in Mortars - Effect of the Use of Limestone Sand Part I: Migration Test

  • Akrout, Khaoula;Ltifi, Mounir;Ouezdou, Mongi Ben
    • International Journal of Concrete Structures and Materials
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    • v.4 no.2
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    • pp.105-108
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    • 2010
  • In order to determine the effect of the use of limestone sand on chloride ion ingress in mortar, specimens were cast with two different sands: siliceous sand (used as reference) and limestone crushed sand (used for this study). To compare and assess the resistance of this mortar to chloride penetration, two different diffusions tests were employed: slow migration and rapid migration (AASHTO test). In this study, calculation of the effective diffusion coefficient is proposed using a model based on Nernst. Planck equation. The diffusion coefficients from each sample were compared. The results for all tests show that the diffusion coefficients for siliceous sand mortar are larger than those obtained with limestone sand. It appears also that the diffusion coefficient varies as a function of the W/C ratio.