• 한국건설순환자원학회지
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• 제15권3호
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• pp.33-39
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• 2020

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.322-325
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• 2003

Recently, as quality river aggregates like sands and gravels become scarce, use of crushed stones and sands, seashore sands, and seashore gravels is increasing abruptly. And, aggregates recycled from slags and waste concretes are used. However, since the converter slag easily expands and breaks due to free lime, differently from the blast-furnace slag, it is not suitable for use as concrete aggregates. Since the atomized steel slag aggregate has slippery surface and spherical shape, the mortar flowing characteristics improved as the atomized steel slag content increases, without regard to the aggregates coarseness and water/cement ratio. The flow characteristics loss rate of the mortar manufactured from steel slag aggregates was similar to that of the mortar manufactured from washed sand only. The compact strength of the mortar manufactured from coarse PS Ball were larger than that manufactured from washing sand only.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.73-78
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• 2001

Portland cement concrete is made with coarse aggregate, fine aggregate, portland cement, water and, in some cases, selected chemical admixtures such as air-entraining agents, water reducer, superplasticizer, and so on, and mineral admixtures 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 final mix. Therefore, the coarse and fine aggregates affect to the properties of the portland cement concrete. As the natural sands are drained, it is necessary and economical to utilize crushed sands(manufactured fine aggregate). It is reported that crushed sands differ from natural sands in gradation, particle shape and texture, and the micro fines in the crushed sands 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 high content of micro fines. This study provides firm data for the use of crushed sands with higher micro fines.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.348-351
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• 2004

In this study, the recycled concrete aggregates crushed in-situ were used for the access road pcc (portland cement concrete) pavement. Based on laboratory results, the properties of materials, mixture proportioning, blend rates, and application conditions were investigated prior to trial application, and the various problems on recycled concrete aggregate under construction have been comprehensively checked.

• Structural Engineering and Mechanics
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• 제47권4호
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• pp.545-557
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• 2013

Disposal of construction wastes poses major challenge to the municipal administration in the developing countries. At the same time new developments in these countries are unscrupulously exploiting the natural resources. The sustainable development requires judicious and careful utilization of natural resources. In this context, reuse of construction and demolition waste can save the global natural resources to greater extent. In this work the bricks and concrete waste from construction sites were crushed to the desired sizes and mixed in various proportions to study its properties in the concrete both in fresh and hardened states. Six mixes of natural and recycled aggregates were used to make the coarse aggregates for the concrete. From each mix nine cylinders were cast, which were tested at 7,14 and 28 days. The properties of concrete with recycled aggregates were compared with the control mix having natural aggregates. The nominal ratio of cement sand and coarse aggregates were kept at 1:2:4 by weight for all mixes. The tests have shown that concrete with recycled aggregates made from old concrete and brick bats provide greater opportunities for reuse of construction wastes in concrete.

• Geomechanics and Engineering
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• 제34권2호
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• pp.173-186
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• 2023

In order to prevent environmental pollution, initiatives to increase the sustainability of resources are supported by society. However, the performance of recycled materials does not generally match that of natural materials. This study looks into the use of geogrid to improve various types of recycled aggregates. For this purpose, five different recycled aggregates were created by recycling wastes from the construction industry. Besides, direct shear tests (DS tests) were carried out on these recycled aggregates to determine their shear strengths. Following that, a triaxial geogrid was placed in the recycled aggregates to provide reinforcement, and the DS tests were conducted on the reinforced recycled aggregates. The results of the tests were also compared to those of tests performed on natural aggregates (NA). In conclusion, it was found that the recycled aggregates have lower shear strengths than the NA. Nonetheless, when reinforced with geogrid, the shear strength of the recycled concrete aggregates (RCA) and construction and demolition wastes (CDW) exceeded that of the NA. Furthermore, the geogrid reinforcement increased the shear strength of the recycled crushed bricks (CB), though not to the level of the NA.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.171-174
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• 1999

The objective of this study is to investigate the properties of fine particles in the process of producing crushed fine aggregates under various fine particle contents. According to the test results, when fine particles are added as substitution of aggregates by about 10%, it shows that the qualities of interlocking block such as compressive strength, flexural strength and absorption ratio are improved. The application of fine particles provide various advantages in the sides of recycling of materials

• 자원환경지질
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• 제53권6호
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• pp.755-769
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• 2020

2019년에 국내에서 채취된 골재에 대하여 광역시도별로 채취현황분석을 실시하였다. 2019년에 전국에서 채취된 골재는 약 1억3천4백만 ㎥로 이 중 모래는 약 4천1백만 ㎥, 자갈은 약 9천3백만 ㎥가 채취되었다. 골재원별로는 선별 파쇄골재(50.3%)가 가장 많이 채취되었으며, 산림골재(41.4%), 육상골재(3.3%), 바다골재(1.7%), 선별세척(1.7%), 하천 골재(0.7%) 순이다. 이는 선별파쇄골재와 산림골재가 국내 골재채취의 주생산지임을 말해준다. 권역별로 보면 경기도가 국내 골재 채취의 약 30%를 점하며, 그 다음으로 경상남도, 충청북도, 강원도, 경상북도, 충청남도의 순이다. 주로 채취되는 골재는 지역적으로 차이가 있다. 경기도는 선별파쇄골재가 가장 많이 채취되며, 경상남도는 산림골재가 가장 많이 채취된다. 또한 육상골재는 경상북도와 강원도에서 채취가 가장 많이 되는 등 지역에 따라 채취가 용이한 골재의 종류가 다르다. 2019년도 골재채취의 특징은 하천골재와 바다골재의 채취가 현저히 줄어든 반면 선별파쇄와 산림골재의 채취가 증가하여 전체 골재채취물량의 약 90%가 넘는다는 것이다. 따라서 골재자원의 향후 수급에 있어 선별파쇄와 산림골재에 우선적인 정책방향이 있어야 할 것으로 판단된다.

• Computers and Concrete
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• 제21권1호
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• pp.39-46
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• 2018

With the increase in industrialization and urbanization, growing demand has enhanced rate of new constructions and old demolitions. To avoid serious environmental impacts and hazards recycled concrete aggregates (RCA) is being adopted in all over the world. This paper investigates successive recycled coarse aggregates (SRCA) in which old concrete made with RCA in form of concrete cubes was used. The cubes were crushed to prepare new concrete using aggregates from crushing of old concrete, used as SRCA. The mechanical behavior of concrete was determined containing SRCA; the properties of SRCA were evaluated and then compared with natural aggregates (NA). Replacement of NA with SRCA in ratio upto 100% by weight was studied for workability, mechanical properties and microstructural analysis. It was observed that with the increase in replacement ratio workability and compressive strength decreased but in acceptable limits so SRCA can be used in low strength concretes rather than high strength concrete structures.

• 콘크리트학회논문집
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• 제27권5호
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• pp.531-539
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• 2015

잔골재 표준입도를 고려하여 조파쇄 바텀애시를 혼입한 일반강도 모르타르의 성능을 실험적으로 분석하였다. 비교군으로서, 파쇄하지 않은 일반 바텀애시를 천연잔골재와 단순 치환하여 사용하였다. 바텀애시를 결합재와 일반 잔골재 사이의 입도를 갖도록 굵게 파쇄할 경우, 입자의 흡수율 및 표건상태 비중이 일반 잔골재 수준으로 조절되었다. 잔골재 표준입도를 고려해 조파쇄 바텀애시를 혼입하는 방법은, 바텀애시 원재료를 일반 잔골재와 단순 치환하던 기존의 배합방법에서 발생하던 모르타르의 유동성 감소 및 강도 감소를 동시에 막을 수 있는 해법이 될 수 있음을 확인하였다. 조파쇄 바텀애시를 30% 이내로 모르타르에 혼입할 경우, 모르타르의 동탄성계수 및 건조수축은 일반골재 모르타르에 비해 크게 변화하지 않았다.