• Title, Summary, Keyword: Sand

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An Experimental Study on the Engineering Properties and B.P Test of Ready Mixed Concrete Using EEZ Sand and Crush Sand (부순모래와 EEZ모래를 혼합사용한 레미콘의 B.P실험 및 공학적 특성에 관한 연구)

  • Shin, Seung-Bong;Kim, Young-Sun;Kim, Young-Duck;Lee, Sung-Yon;Kim, Gyu-Yong;Kim, Moo-Han
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.105-108
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    • 2006
  • Recently, trouble of sand supplying is occurred according to exhaustion of natural sand resources. Therefore various measures are proposed for solution of trouble of sand supply and crushed sand among measures is used as one of most universal measures. But because crushed sand have poor particle shape and plenty of mikes micro particle, the quality of concrete using crushed sand deteriorated. Therefore, this study evaluated engineering property of concrete with replacement ratio of crushed sand and EEZ sand applied evaluation result to fundamental data for quality control of concrete using crushed sand and EEZ sand and The result of this study have shown that quality of concrete using crushed sand and EEZ sand and The compressive strengh of concrete up to 50, 70% EEZ sand replacement by crush sand, nearly equal to that of general sand.

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Effect of hanging-type sand fence on characteristics of wind-sand flow fields

  • Cheng, Jian-jun;Lei, Jia-qiang;Li, Sheng-yu;Wang, Hai-feng
    • Wind and Structures
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    • v.22 no.5
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    • pp.555-571
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    • 2016
  • A hanging-type sand-retaining wall is a very common sand-blocking fence structure used to prevent sand movement. This type of wall is widely used along the Qinghai-Tibet and Gobi desert railways in Xinjiang, Western China. To analyze the characteristics of wind-sand flow fields under the effect of such a sand fence structure, a wind tunnel test and a field test were carried out. The wind tunnel test showed the zoning characteristics of the flow fields under the effect of the hanging-type sand-retaining wall, and the field test provided the sediment transport data for effective wind-proof interval and the sand resistance data in the front and behind the sand-retaining wall. The consistency of the wind-sand flow fields with the spatial distribution characteristic of wind-carried sand motion was verified by the correspondences of the acceleration zone in the flow field and the negative elevation points of the percentage variations of the sand collection rate. The spatial distribution characteristic of the field sand collection data further showed the spatial structural characteristic of the sandy air currents under the action of the hanging-type sand-retaining wall and the sand resistance characteristic of the sand-retaining wall. This systematic study on the wind-sand flow fields under the control of the hanging-type sand-retaining wall provides a theoretical basis for the rational layout of sand control engineering systems and the efficient utilization of a hanging-type sand-retaining wall.

A Study on the Properties of Cement Mortar Using Blended Sand (혼합모래를 사용한 시멘트 모르터의 특성에 관한 연구)

  • Park Yong-Kyu;Kim Min-Ho;Yoon Gi-Won;Ryu Hyun-Gi;Han Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.65-68
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    • 2005
  • This paper investigated the engineering properties of cement mortar mixed with more than 2 kinds of sand. For fresh mortar properties, unit volume weight is constant regardless of mixing content and type of sand. An increase in contents of river and crushed sand resulted in an increase in flow, whereas an increase in recycled sand contents reduced flow. Gap between maximum flow in N3C0R0 and minimum flow in N0C0R3 exhibited about $12\%$. Compressive strength at 28 days ranged from 32 to 36 MPa in order for crushed sand, river sand and recycled sand. Mortar with mixed sand along with river sand and crushed sand showed compressive strength comparable to crushed sand. An increase of fraction of recycled sand in mixed sand resulted in a decrease in compressive strength. For drying shrinkage, N0C0R3 had the largest drying shrinkage among various mixture type. The combination of large contents of recycled sand and small contents of river and crushed sand had a large amount of drying shrinkage.

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An Experimental Study on the Properties of Fresh and Hardened Ready Mixed Concrete Using EEZ sand and Crush sand (EEZ모래와 부순모래를 사용한 레미콘의 굳지않은 성상 및 경화성상에 관한 연구)

  • Shin Seung-Bong;Koo Kyung-Mo;Na Chul-Sung;Ryu Jae-Chul;Kim Gyu-Yong;Kim Moo-Han
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.53-56
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    • 2006
  • Recently, trouble of sand supplying is occurred according to exhaustion of natural sand resources. Therefore various measures are proposed for solution of trouble of sand supply and crushed sand among measures is used as one of most universal measures. But because crushed sand have poor particle shape and plenty of makes micro particle, the quality of concrete using crushed sand deteriorated. Therefore, this study evaluated engineering property of concrete with replacement ratio of crushed sand and EEZ sand and applied evaluation result to fundamental data for quality control of concrete using crushed sand and EEZ sand. The result of this study have shown that quality of concrete using crushed sand and EEZ sand and The compressive strength of concrete up to 50, 70% EEZ sand replacement by crush sand, nearly equal to that of general sand.

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An Experimental Study on the Physical Properties of Mortar Using EEZ Sand and Crushed Sand (부순모래와 EEZ모래를 혼합사용한 모르타르의 기초물성에 관한 실험적 연구)

  • Park Jong-Ho;Jang Jae-Bong;Na Chul-Sung;Cho Bong-Suk;Kim Jae-Hwan;Kim Moo-Han
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.33-36
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    • 2005
  • Recently, Trouble of sand supply is occurred according to exhaustion of natural sand resources. therefore, various measures are proposed for solution of trouble of sand supply. also the government settled trouble of sand supply through application of EEZ sand and crushed sand. but because both EEZ sand and crushed sand are poor against general sand, they lead to lowering of quality of ready-mixed concrete. Therefore, this study evaluated physical properties of mortar using EEZ sand and crushed sand and applied evaluation result to fundamental data The result of this study have shown that quality of mortar using EEZ sand and crushed sand independently is poor against general mortar. but, mortar flow and compressive strength is increased in case of mixing 222 sand and crushed sand properly.

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An Experimental Study on the Durability of Concrete with a Source of Supply of Sand (잔골재의 원산지에 따른 콘크리트의 내구특성에 관한 실험적 연구)

  • Park, Jong-Ho;Hong, Ji-Hun;Kim, Jung-Bin;Park, Se-Jong;Park, Chang-Su;Lee, Sung-Yeon
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.137-140
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    • 2006
  • This study make an investigation into the quality of sand supplied with remicon manufacturing plant and examine concrete influenced by a source of supply of sand. As a result of the indoor test, the quality of crushed sand, EEZ sand and sand of north korea are worse than general sea sand. therefore, crushed sand, EEZ sand and sand of north sand lower quality of concrete.

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Standard sand for geotechnical engineering and geoenvironmental research in Nigeria: Igbokoda sand

  • Ojuri, Oluwapelumi O.;Fijabia, David O.
    • Advances in environmental research
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    • v.1 no.4
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    • pp.305-321
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    • 2012
  • This study entails establishing reference standard sand in Nigeria for engineering and geoenvironmental research work. Sands from four geographical locations in southwestern Nigeria were examined for baseline geotechnical and mineralogical properties. A total of sixteen sand samples were collected. The samples were air dried and subjected to tests in accordance with standard specifications. The tests carried out were: specific gravity, grain size analysis, moisture content, bulk density, porosity, void ratio, chemical analysis, X-ray diffraction and Differential Thermal Analysis. The properties of the samples were compared with a standard (Ottawa sand in Illinois of the United States) in order to find out which of the four samples selected from southwestern Nigeria could serve as standard baseline sand. The results show that Igbokoda sand has geotechnical and mineralogical characteristics closest to Ottawa sand. It was therefore concluded that Igbokoda sand could be used as a standard baseline sand for research work in southwestern Nigeria and other parts of Nigeria since it needs little processing to bring it to the same level as standard baseline sand, like the Ottawa sand.

The motion rule of sand particles under control of the sand transportation engineering

  • Xin, Lin-gui;Cheng, Jian-jun;Chen, Bo-yu;Wang, Rui
    • Wind and Structures
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    • v.27 no.4
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    • pp.213-221
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    • 2018
  • In the desert and Gobi regions with strong wind and large sediment discharge, sand transporting engineering is more effective than sand blocking and sand fixing measures in sand prevention. This study uses the discrete phase model of 3D numerical simulation to study the motion trail, motion state and distribution rule of sand particles with different grain diameters when the included angle between the main shaft of the feather-row lateral transportation sand barrier and the wind direction changes, and conducts a comparison in combination with the wind tunnel test and the flow field rule of common sand barrier. According to the comparison, when wind-sand incoming flow passes through a feather-row sand barrier, sand particles slow down and deposit within the deceleration area under the resistance of the feather-row sand barrier, move along the transportation area formed by the transportation force, and accumulate as a ridge at the tail of the engineering. With increasing wind speed, the eolian erosion of the sand particles to the ground and the feather-row sand barrier is enhanced, and the sand transporting quantity and throw-over quantity of the feather-row sand barrier are both increased. When sand particles with different grain diameters bypass the feather-row sand barrier, the particle size of the infiltrating sands will increase with the included angle between the main shaft of the feather-row sand barrier and the wind direction. The obtained result demonstrates that, at a constant wind speed, the flow field formed is most suitable for the lateral transportation of the wind-drift flow when the included angle between the main shaft of the feather-row sand barrier lateral transportation engineering and the wind speed is less than or equal to $30^{\circ}$.

Study on the Properties of Antiwashout Underwater Concrete with Variation of Blend Ratio of Crushed Sand (부순모래 혼입률 변화에 따른 수중불분리성 콘크리트의 특성 연구)

  • 박세인;오광영;이환우;김종수;김명식
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.427-432
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    • 2001
  • In this study, crushed sand is blended with river sand and sea sand, to investigate the quality change of antiwashout underwater concrete with variation of blend ratio of crushed sand(0%, 20%, 40%, 60%, 80%, 100%). To see experiment conclusion, the more blend ratio of crushed sand increases, the more unit weight increases. Because the for that specific gravity of crushed sand is higher comparatively than that of river sand and sea sand. Higher compressive strength is measured following the order of river sand, crushed sand, sea sand regardless of age and casting-curing condition. Except for case of using river sand, blend ratio of 40% is appeared on most compressive strength. So the optimum blend ratio of crushed sand is 40% from the view point of compressive strength.

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An Experimental Study on the Engineering Property of Concrete With Replacement Ratio of Crushed Sand (부순모래 대체율에 따른 콘크리트의 공학적 특성에 관한 실험적 연구)

  • Park Jong Ho;Lee Eui Bae;Choi Se Jin;Lee Seong Yeun;Kim Gyu Yong;Kim Moo Han
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.451-454
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    • 2005
  • Recently, Trouble of sand supply is occurred according to exhaustion of natural sand resources. therefore, various measures are proposed for solution of trouble of sand supply and crushed sand among measures is used as one of most universal measures. but because crushed sand have poor particle shape and plenty of makes micro particle, the quality of concrete using crushed sand deteriorated. Therefore, this study evaluated engineering property of concrete with replacement ratio of crushed sand and applied evaluation result to fundamental data for quality control of concrete using crushed sand. The result of this study have shown that quality of concrete using crushed sand independently is poor against general concrete. but, the concrete mixing crushed sand with general sand can be similar in workability of concrete used general sand and increase compressive strength of concrete as against concrete using general sand.

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