• 한국건축시공학회지
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• 제3권3호
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• pp.107-112
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• 2003

This study is to investigate the properties of concrete with crushed sand on site and to propose a quality guideline for its use as artificial sand and concrete. From our experimental result in laboratory and site, we found that demand water of concrete with crushed sand for target slump increased by 18kg/m3 compared to mixed sand and l8kg/m3 compared to sea sand respectively. The compressive strength increased by around 3∼6% when compared to concrete with sea sand. Accordingly, our study showed that the combined sand mixed with sea sand would be desirable to obtain workability and strength of concrete including dry shrinkage and bleeding test. Furthermore, the optimal replacement percentage of crushed sand was 50% with sea sand. As such, crushed sand would be sufficient as fine aggregate for concrete in terms of economic efficiency and quality. Crushed sand, on the other hand can only be used as fine aggregate when VFS(Very Fine Sand) is below 3.5 percentage of weight of sand and particle shape is above 55 percentage. Also, the particle shape and microsand passing NO.200 sieve should continually be improved to increase workability of concrete on site.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.497-500
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• 2006

In this paper, study on applicability and quality control of the concrete using crushed sand. Recently, Trouble of sand supply is occurred according to exhaustion of natural sand resources. Now, application of crushed sand are proposed for solution of trouble of sand supply. Therefore, this study evaluated properties of concrete using crushed sand which mixing rate and changing FM.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2005년도 추계 학술논문 발표대회
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• pp.17-20
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• 2005

This study investigates mock-up test of the concrete containing crushed sands with improved quality and following could be draws as conclusions. The slump satisfies the target value. The air content reaches the goal, however, it decreases by the occurrence of loss with elagse of age. In normal strength region, the setting time of CS24 member is shorter than that of SS24 member. In high strength region, the setting time of SS50 member is make only slower than that of CS5O because of the use of retarding AE agent. The compressive strength of the concrete using crushed sands is little higher than the concrete using washed sea sands, and the compressive strength of core sample increases at lower part. Drying shrinkage of the concrete using crushed sands is larger than that using washed sea sands. At water caring condition, both the concrete using crushed sands and using washed sands expand at first, exhibit to be swelled and with elagse of age, they remain relatirely constant. Also, the drying shrinkage occurred greatly when the width and thickness of a member are small because it is easy to evaporate the inner part vapor in the small width and thickness of a member. there can be little different according to the location of a contact gauge, however it is similar to the change of specimen's length change. The concrete using crushed sands, of which grading, grain shape and fine particle is improved, are comparable to the quality of the concrete using washed sea sand.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2006년도 춘계학술논문 발표대회 제6권1호
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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.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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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.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.383-386
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• 2005

This paper is to investigate the effect of W/B, blend ratio of crushed sand with sea sand on fluidity and strength properties of high strength concrete utilizing crushed sand. W/B set up 0.25, 0.30, 0.35 and the blend ratio of crushed sand with sea sand set up 0:100, 30:70, 50:50, 70:30, 100:0 The results of this study are summarized as the follows; 1) The increase of the blend rate of crushed sand, affected on the enhancement of flow, the increase of dosage of SP and water content, but the decrease S/a 2) Compressive strength is increased when crushed sand $30\~70\%$ was replaced with sea sand. 3) The optimal replacement percentage of crushed sand is $50\%$ with sea sand.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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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.

• 한국건설순환자원학회논문집
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• 제3권3호
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• pp.244-251
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• 2015

본 연구는 대경권 지역에서 생산되는 부순모래를 콘크리트용 잔골재로 활용하기 위하여 물리적 특성 및 부순모래의 조립률과 치환률이 콘크리트의 특성에 미치는 영향을 검토하였다. 실험결과 천연사의 조립률이 2.0정도이고, 부순모래 조립률이 3.2이상인 경우 천연사와 부순모래의 합성입도를 만족시키기 위한 부순모래의 치환률은 50% 이하가 적당한 것으로 나타났다. 부순모래를 사용한 콘크리트는 부순모래의 치환률이 증가할수록 슬럼프는 증가하는 것으로 나타났으나, 부순모래의 치환률 75% 이상에서는 현저한 워커빌리티 저하현상을 나타내었다. 또한 부순모래를 사용한 콘크리트의 공기량 및 블리딩은 부순모래 치환률이 증가할수록 감소하였으며, 콘크리트 압축강도는 부순모래 조립률에 관계없이 시멘트페이스트와 골재간의 부착력 증진에 기인하여 치환률이 증가할수록 증가하는 경향을 나타내었다.

• 대한토목학회논문집
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• 제26권1A호
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• pp.229-236
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• 2006

최근 암석을 깨어 제조한 부순모래의 사용량이 꾸준히 증가되어 전체 잔골재 사용량의 20%에 가깝게 사용되고 있고, 향후에도 부순모래의 사용량은 계속 증가할 것으로 판단된다. 그러나 부순모래 생산 시 품질에 대한 인식 부족 등으로 KS F 2527 기준을 만족하지 않은 부순모래가 콘크리트 제조 시 사용되는 것으로 조사되고 있으나, 이런 부순모래가 콘크리트에 미치는 영향에 대해 체계적으로 검토한 연구가 거의 없는 실정이다. 따라서 본 연구에서는 부순모래의 입형이 콘크리트 품질에 미치는 영향에 대해 분석함으로써 부수모래를 콘크리트에 활용할 수 있는 자료를 제시하고자 한다. 현재 KS F 2527의 기준인 입자모양 판정 실적률 53% 부순모래를 사용한 콘크리트는 시공성, 공기연행성 및 내구성 등에서 문제가 있는 것으로 나타났다. 그리고 부순모래를 사용한 콘크리트의 품질을 향상시키기 위해 특히 고강도 콘크리트에서 입자모양 판정 실적률은 현행 KS 기준인 53%에서 55%으로 조절해야 할 것으로 분석되었다.

• 한국농공학회지
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• 제44권2호
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• pp.107-116
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• 2002

The amount used of aggregates for concrete is increasing rapidly since the mid-1980s in Korea. The natural gravels from river are already displaced with crushed stone, and use of crushed sand as a substitute of natural river sands, also, is getting increased day by day. This paper is presented fur analysis on mechanical properties of high strength concrete using fly ash and crushed sand. The material functions in mixing design of concretes are various water-cement ratios(w/c) such as 0.25, 0.40, 0.55 and different replacement ratio of crushed sand to natural sands such as 0%, 20%, 40%, 60%. As a results, it has been shown that compressive strengths of concretes with W/C lower than 0.40 and 0.25 are higher than 400 kgf/$\textrm{cm}^2$ and 600 kgf/$\textrm{cm}^2$ respectively. It is also concluded that the results of rapid chloride permeability tests of concrete are evaluated to negligible. The conclusions of this study is that it is possible to use fly ash and crushed sand fur high strength concrete.