• 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.

• 한국지반환경공학회 논문집
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• 제7권6호
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• pp.67-73
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• 2006

본 연구에서는 하수관거의 기초나 뒷채움재로 많이 사용되고 있는 기존의 모래를 대체할 재료로써 석분의 적용가능성을 평가하기 위하여 석분재료에 대한 기본적인 물리적, 역학적인 특성실험을 실시하였다. 석분의 입도분포는 모래보다 더 좋은 상태를 나타내며, 다짐실험 결과도 모래보다 강도특성이 좋은 것으로 나타났다. 이러한 실험결과로부터 하수관거의 기초 및 뒷채움재로써 석분은 현장적용성이 우수한 것으로 평가되며, 이를 뒷받침하기 위하여 직접전단시험, 삼축압축시험을 실시하여 강도특성을 분석한 결과 모래의 경우와 유사한 경향을 나타내었다. 석분의 경우 일축압축강도 특성은 시간이 지남에 따라 점차 증가하는 경향을 보이지만 6~7일 경과 후에는 거의 일정한 값을 보이는 것을 알 수 있었다. 이와 같은 실험결과로부터 석분도 하수관거의 기초 및 뒷채움재로 충분히 활용할 수 있는 재료로 평가되었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 가을 학술발표회 논문집
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• pp.10-16
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• 1996

This study is aimed for investigating a decision of the saturated surface dry of crushed stone sand and measuring the moisture with increasing percentage of VFS(Very Fine Sand) replacement each crushed stone sand. The results indicated that moisture of crushed stone sand is generally increased with increasing percentage of VFS replacement and the rate of increase of moisture is about 30% every time that VFS replacement increases 3.5%. Also the saturated surface dry for crushed stone sane is proposed as a point of time where shape of flow-cone first slumps in this paper.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.941-946
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• 2001

In this study, three kinds of fine aggregate (river sand, sea sand, crushed sand) were used and four different s/a (38%, 40%, 42%, 45%) were applied separately to this experimental for get the conclusion written below. Regardless of kinds of fine aggregate and casting-curing condition, maximum unit weight is seen at 40% of s/a and also to be seen in case of crushed sand. It's for that specific gravity of crushed sand is bigger comparatively than river sand and sea snad's one. Compressive strength is measured river sand, crushed sand, sea sand by order of size ; Regardless of variation of s/3, casting-curing condition and age. Compressive strength recorded maximum when s/a is 42% whatever sort of fine aggregate are. As the result, according to references, the optimum s/a of underwater antiwashout concrete is 40% but in this study, from compressive strength of view, the optimum s/a of underwater antiwashout concrete is 42%.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.317-322
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• 2001

This paper investigates the influence of fine aggregates on bleeding of concrete. According to test results, as water content decreases, crushed sand content increases, fluidity shows decline tendency. As for aggregates kinds, concrete using sea sand shows most fluidity loss among the tested results. Compressive strength gains highly when crushed sand is used. As for bleeding of concrete, bleeding shows decline tendency because of increasing in powder content and filling effect of voids. Bleeding amount is in a decreasing order of magnitude for concretes made with the following aggregates: sea sand, river sand, and crushed sand. Accordingly, crushed sand mixed with river sand and sea sand with certain proportion enable to reduce bleeding and enhance strength.

• 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.

• International Journal of Concrete Structures and Materials
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• 제3권1호
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• pp.11-14
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• 2009

This paper is interested in the incorporation of crushed sand and desert sand in the composition the self compacting concretes (SCC). Desert dune sand, which has a fine extra granulometry, and the crushed sand, which contains an important content of fines, can constitute interesting components for SCC. Part II consists in studying the behaviour of SCC containing various sands with different origins. These sands, with different sizes, consist of several combinations of rolled sand (RS), crushed sand (CS) and desert sand (DS). The study examines the influence of the granular combination of sands on the characteristics in the fresh and the hardened state of SCC. The results of the experimental tests showed an improvement of the workability of the fresh SCC by combining sands of varied granulometry. The addition of the DS to CS or to RS allowed the increase of the mixture viscosity but decreased the mechanical strengths. Furthermore, the CS-RS combinations increased the compressive and the tensile strengths of the studied SCC. The optimized formulations of sands gave the highest performances of the SCC.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회논문집(II)
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• pp.661-664
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• 1998

In this paper, the properties of inter-lacking block by the kind of aggregate and fineness modulus are investigated. According to the experimental results, compressive strength and flexural strength increase and absorption ratio decrease with larger fineness modulus in the range of 2.15~4.20. Flexural strength with river sand is higher than that with crushed sand by about 19%, compressive strength with river sand, that with crushed sand by about 11% and absorption ratio with river sand is smaller than that with crushed sand by abort 2%.

• 한국건설순환자원학회논문집
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• 제5권2호
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• pp.168-176
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• 2017

본 연구에서는 원전 구조물용 콘크리트의 잔골재로 부순모래를 사용하기 위한 연구의 일환으로 기존의 부순모래 생산공정에서 임팩트크러셔(Impact crusher)의 성능(회전수)을 높여 입형을 개선하고 ASTM C 33에 적합하도록 입도를 조정한 부순모래의 입형 및 입도 특성을 검토하였으며, 강모래에 대한 치환률에 따라 콘크리트를 제조하여 콘크리트 배합 특성, 굳지 않은 콘크리트 특성 및 경화한 콘크리트 특성을 검토하였다. 실험결과, 대부분의 콘크리트 특성이 강모래만을 사용한 콘크리트와 동등한 수준으로 나타났지만, 강모래에 대한 치환률 50% 이상일 경우, 치환률 증가에 따라 허용 범위 내에서 공기량, 압축강도 및 인장강도는 다소 감소되는 것으로 나타났다.

• 한국안전학회지
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• 제16권1호
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• pp.65-72
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• 2001

Portland cement concrete is made with coarse aggregate, fine aggregate, portland cement, water and, in some cases, selected chemical admixture such as air-entraining agents, water reducer, superplasticizer, and so on, and mineral admixture such as fly ash, silica fume, slags, etc. Typically, in the concrete, the coarse aggregate and fine aggregate will occupy approximately 80 percent of the total volume of the finished mixture. Therefore, the coarse and fine aggregates affect to the properties of the portland cement concrete. As the deposits of natural sands have slowly been depleted, it has become necessary and economical to produce crushed sand(manufactured fine aggregate). It is reported that crushed sand differs from natural sands in gradation, particle shape and texture, and that the content of micro fines in the crushed sand affect to the quality of the portland cement concrete. Therefore, the purpose of this paper is to investigate the characteristics of fresh and hardened concrete with higher micro fines. This study provides a firm data to apply crushed sand with higher micro fines.