• 한국전산구조공학회논문집
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• 제30권1호
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• pp.55-61
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• 2017

최근 콘크리트 궤도 슬래브 하면과 교량 바닥판 사이에 저마찰 슬라이드층을 형성하는 궤도 시스템인 슬라이딩 궤도와 관련된 연구가 활발히 진행되고 있다. 본 연구에서는 슬라이딩 궤도에서 열차 주행에 따른 횡방향 하중을 저항하기 위해 설치되는 횡방향 지지 콘크리트 블록의 전단 내하력에 대한 연구를 수행하였다. 횡방향 지지 콘크리트 블록의 전단 내하력 산정을 위해 타설경계면에서의 콘크리트 마찰 및 철근의 다월 거동을 고려한 산정 기법을 개발하다. 제안된 산정 기법은 기존의 실험에서 측정된 전단 내하력을 13~23% 정도 보수적으로 예측하는 것으로 나타났다. 이는 균열면 골재 맞물림 효과를 무시한 것에 따른 것으로, 현장에서의 타설경계면 상태가 불확실한 것을 고려할 때 횡방향 지지 콘크리트 블록에 대한 안전측 설계를 위해 제안된 산정 기법이 합리적인 것으로 판단된다. 제안된 전단 내하력 산정 기법을 토대로 횡방향 지지 콘크리트 블록에 대한 설계 방안을 마련하였다.

• Computers and Concrete
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• 제32권4호
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• pp.351-363
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• 2023

Reducing the self-weight of reinforced concrete structures problem is discussed in this paper by using two types of self-weight reduction, the first is by using lightweight coarse aggregate (crushed brick) and the second is by using styropor block. Experimental and Numerical studies are conducted on (LWAC) lightweight aggregate reinforced concrete slabs, having styropor blocks with various sizes of blocks and the ratio of shear span to the effective depth (a/d). The experimental part included testing eleven lightweight concrete one-way simply supported slabs, comprising three as reference slabs (solid slabs) and eight as styropor block slabs (SBS) with a total reduction in cross-sectional area of (43.3% and 49.7%) were considered. The holes were formed by placing styropor at the ineffective concrete zones in resisting the tensile stresses. The length, width, and thickness of specimen dimensions were 1.1 m, 0.6 m, and 0.12 m respectively, except one specimen had a depth of 85 mm (which has a cross-sectional area equal to styropor block slab with a weight reduction of 49.7%). Two shear spans to effective depth ratios (a/d) of (3.125) for load case (A) and (a/d) of (2) for load case (B), (two-line monotonic loads) are considered. The test results showed under loading cases A and B (using minimum shear reinforcement and the reduction in cross-sectional area of styropor block slab by 29.1%) caused an increase in strength capacity by 60.4% and 54.6 % compared to the lightweight reference slab. Also, the best percentage of reduction in cross-sectional area is found to be 49.7%. Numerically, the computer program named (ANSYS) was used to study the behavior of these reinforced concrete slabs by using the finite element method. The results show acceptable agreement with the experimental test results. The average difference between experimental and numerical results is found to be (11.06%) in ultimate strength and (5.33%) in ultimate deflection.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.403-408
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• 1998

The analytical model is developed in order to predict the nonlinear flexural responses of bonded and unbonded prestressed concrete beam which contains advanced composite materials. The block concept is used, which be regarded as an intermediate modeling method between the couple method with one block and the layered method with multiple sliced blocks in a section. The model can successfully predict the flexural behavior of variously reinforced prestressed concrete beams.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 가을 학술발표회 논문집
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• pp.44-50
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• 1996

Accumulation of worn-out automobile tires creat fire and health hazards. As a possible solution to the problem of scrap-tire disposal, an experimental study was conducted to examine the potential of using tire chips as aggregate in Railroad block. This paper examines strength and toughness properties of Railroad block in which different amounts of rubber-tire particles of several sizes were used as aggregate. The Railroad block mixtures exhibited lower compressive, bending than did normal block. However, these mixtures did not demonstrate brittle failure, but rather a ductile, plastic failure, and had the ability to absorb a large amount of plastic energy under compressive loads.

• 한국재난정보학회 논문집
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• 제17권2호
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• pp.266-274
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• 2021

연구목적: 본 연구는 보행자의 안전 및 다양한 정보를 제공할 수 있는 바닥용 콘크리트 공공 사인 블록의 개발을 목적으로 한다. 연구방법: 이러한 연구목적을 달성하기 위하여 위하여 공공 사인 블록 개발과 관련하여 적용한 단계별 블록 제작 기술을 제시하고, 개발된 콘크리트 공공 사인 블록의 현장적용성을 평가하였다. 연구결과: 본 연구에서 개발된 바닥용 콘크리트 공공 사인 블록은 다양한 형상의 공공 사인의 표현이 가능하고, 제조 단가를 절감할 수 있을 것으로 보인다. 2년간의 사용성 평가결과 균열, 모서리 탈락, 변색, 마모 등의 문제는 발견되지 않아 충분한 내구성을 확보한 것으로 판단된다. 결론: 이러한 연구 결과를 토대로 콘크리트 공공 사인 블록이 기존의 바닥용 공공 사인에 활용되어 오던 스티커, 석재 및 황동판 등의 취약점을 보안할 수 있는 대안으로 활용될 것으로 보이며, 향 후 블록 디자인의 다양화를 도모하여 여러 분야에 적용될 수 있기를 기대한다.

• Advances in concrete construction
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• 제5권5호
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• pp.451-468
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• 2017

The problem of reducing the self-weight of reinforced concrete structures is very important issue. There are two approaches which may be used to reduced member weight. The first is tackled through reducing the cross sectional area by using voids and the second through using light weight materials. Reducing the weight of slabs is very important as it constitutes the effective portion of dead loads in the structural building. Eleven slab specimens was casted in this research. The slabs are made one way though using two simple supports. The tested specimens comprised three reference solid slabs and eight styropor block slabs having (23% and 29%) reduction in weight. The voids in slabs were made using styropor at the ineffective concrete zones in resisting the tensile stresses. All slab specimens have the dimensions ($1100{\times}600{\times}120mm$) except one solid specimens has depth 85 mm (to give reduction in weight of 29% which is equal to the styropor block slab reduction). Two loading positions or cases (A and B) (as two-line monotonic loads) with shear span to effective depth ratio of (a/d=3, 2) respectively, were used to trace the structural behavior of styropor block slab. The best results are obtained for styropor block slab strengthened by minimum shear reinforcement with weight reduction of (29%). The increase in the strength capacity was (8.6% and 5.7%) compared to the solid slabs under loading cases A and B respectively. Despite the appearance of cracks in styropor block slab with loads lesser than those in the solid slab, the development and width of cracks in styropor block slab is significantly restricted as a result of presence a mesh of reinforcement in upper concrete portion.

• 콘크리트학회논문집
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• 제13권2호
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• pp.87-92
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• 2001

주물공장에서 발생하는 플라이애쉬는 현재까지 그 전부가 매립에 의존하고 있는 상태로 자원절약 및 산업폐기물의 유효이용이라는 측면에서 국가적인 손실이 아닐 수 없다. 따라서 산업폐기물의 유효이용, 콘크리트 제품 제조시 원가 절감, 콘크리트 제품의 품질개선 및 환경보존의 측면에서 플라이애쉬를 시멘트 대체재료로 사용할 수 있도록 이에 대한 연구가 필요하다. 본 연구에서는 주물공장의 폐기물인 플라이애쉬를 건설산업에 활용하는 방안을 수립하는 데 그 목적이 있다. 이를 위하여 주물공장에서 발생하는 플라이애쉬를 시멘트 대체재로 사용한 속빈 콘크리트 블록 및 콘크리트 벽돌을 제작하여, 한국산업규격에 규정한 요구조건에 대한 실험을 실시하였고 제반 특성을 조사하여 콘크리트 제품에 활용할 수 있는 방안을 제시하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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• pp.422-429
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• 1997

Thermal stress induced by hydration heat may produce cracks in mass concrete structure, which can result in structural problems as well as bad appearance. To minimize crack occurrence in massive structural, thus, the study put an emphasis on the determination of optimized lift height and block size. In the parametric study different sizes and lift heights were used to measure the magnitudes of hydration heat and thermal stresses for 3 different types of concrete fabricated with 1 pure cement and 2 blended Portland cements. As a result of analysis. it was found that magnitude of hydration heat and the occurrence of thermal cracks depend on the restriction conditions and material characteristics, especially adiabatic material parameters. It was also found that optimized lift height and block size can be determined from an appropriate combination of the degree of inner and outer structural restrictions.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.461-464
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• 2005

As the research on the development of the lightweight concrete block by the hydro-thermal synthetic reaction mixed with the calcareous material and bottom ash that is used less among siliceous material, we studied on the physical and chemical characteristics in the changes of hydro-thermal synthetic reaction of lightweight concrete block compounded with the PP fiber to increase flexural toughness and to prevent fragility failure. The results of the experiment are as follow. According to the increase of hydro-thermal synthetic reaction and the fiber content, compressive and flexural strength increased. Despite the changes of the hydro-thermal synthetic reaction time, tobermorite was produced on each of the specimens similarly. However, the phase of tobermorite was changed in accordance with the changes of time. Also, $CaCo_{3}$ appeared on the surface of the 9 hour hardened specimen.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.179-180
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• 2018

Color concrete is produced by adding white portland cement and coloring agent. In Korea, colorant added to color concrete is expensive, durability evaluation in external environment is not verified and there is a tendency to avoid color concrete pouring. Red mud with a water content of 50% was prepared in liquid form using appropriate mixing water and additives for recycling as a coloring agent, the liquefied red mud manufactured was intended to show the possibility of using color concrete. In this paper, the application of red mud as an industrial by - product as a coloring agent for color concrete was investigated for the practical use of liquefied red mud by liquefying red mud and producing retaining wall block. As a result, it was found that all of the specifications stipulated in SPS-KCIC0001-0703 are satisfied.