• 농업과학연구
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• 제37권2호
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• pp.277-283
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• 2010

Research on permeable pavement like asphalt and concrete pavement with porous structure has been increasing due to environmental and functional need such as reduction of run off and flood. This study was performed to evaluate void ratio, permeability coefficient, and compressive strength of permeable polymer concrete (PPC) using crushed and recycled coarse aggregate that is obtained from waste concrete. Also, 6 mm length of polypropylene fiber was used to increase toughness and interlocking between aggregate and aggregate surrounded by binder. Binder and filler used were unsaturated polyester resin and CaCO3, respectively. The mix proportions were determined to satisfy the requirement for the workability and slump according to aggregate sizes 5~10 mm. In the test results, regardless of kinds of aggregates and fiber contents, the void ratio, permeability coefficient and compressive strength of all types of PPC showed the higher than the criterion of porous concrete that is used in permeable pavement in Korea. Also, strengths of PPC with increase polypropylene fiber volume fraction showed slightly increased tendency due to increase binder with increase of fiber volume fraction. Accordingly, polypropylene fiber and recycled coarse aggregate can be used for permeable pavement.

• 한국화재소방학회논문지
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• 제18권1호
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• pp.31-36
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• 2004

본 연구는 잔골재 및 혼화재 종류, W/C에 따른 콘크리트의 폭열성상 및 압축강도 초음파속도 등의 공학적 특성을 검토함으로서 폭열 방지 및 화재 피해를 입은 콘크리트 구조물의 재사용과 보수보강, 안전도평가 등에 기초적인 자료를 제시하고자 한다. 폭열성상을 살펴보면, 잔골재에 따라서는 바다모래를 사용한 경우 폭열이 발생하지 않았거나 약간의 폭열이 나타나는 정도이나 재생잔골재나 부순모래를 사용한 경우에는 폭열이 심하게 나타났다. 또한 혼화재 종류에 따라서는 대체로 유사한 폭열성상을 나타내었다. 한편, W/C 30.5%의 고강도 영역에서는 대부분 폭열하였으나 W/C 55%의 보통강도 영역에서는 대부분 폭열하지 않았다. 잔존 압축강도는 W/C 55%의 경우 평균 45%로 나타났으며, W/C 30.5%의 경우에는 평균 64％로 나타났다. 초음파속도는 잔골재 종류 및 W/C, 가열시간에 따라 다르게 나타났으며, 가열 후 3개월이 가열 후 1개월보다 약 1.3∼8.4%의 초음파속도 회복을 보였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 봄 학술발표회 논문집
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• pp.101-106
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• 1996

In this study, filling performance of concrete is investigated experimentally for the developmenmt of the concrete to be used in concrete filled steel tubular columns with inner diaphrams. Water-cement ratio with 3 levels, unit water contents with 5 levels, unit coarse aggregate contents with 5 levels, and slump flow with 3 levels are selected for test variables. For the estimation of the filling properties of the concrete, slump flow, V-type funnel time, U-type box height are measured and compared. A device which simulates the steel tubular column is designed and three kinds of concrete are tested with it. As the results, the filling performance is decreased with increasing coarse aggregate content. And, within the scope of this study, concretes with coarse aggregate content less than 880 kg/$\textrm{m}^3$ show good filling performance. To prevent excessive settlement of the concrete pumped into the steel tubular column, slump flow should be controlled within the limited range.

• 콘크리트학회논문집
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• 제12권5호
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• pp.93-99
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• 2000

The physical properties of freshly mixed steel fiber reinforced recycled concrete(SFRRC) were_investigated. Physical state and quality of fresh concrete were monitored batch by batch. the properties of freshly mixed SFRRC were determined in terms of slump, air content, superplasticizer, and bleeding ratio. Concrete mixtures were produced for three kinds of aggregate proportions. So, the experimental variables are various aggregate proportions, steel fiber contents(0, 0.5, 1.0, 1.5%) and steel length(30, 50, 60mm). From experimental results, optimum s/a by various experimental variables, variations of the slump by the air contents, and optimum superplasticizer to decrease unit water were presented.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.187-190
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• 1999

This study is intended to present the properites of planting concrete using the light-weight aggregate and crushed aggregate. According to the result of experiment, the concrete using orchid stone shows a better performance in voids volume, unit weight, absorbtion, thermal conductivity and pH, which are helpful for planting and heat isolation. Therefore, if planting concrete used with orchid stone are utilized to be the planting base on the building's roof, it will be effective to reduced the cost of construction and heating due to the redution of building's self weight and heat isolation effection.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 추계 학술논문 발표대회
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• pp.154-155
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• 2016

Oyster shell is light weighted and its strength characteristic is similar to sand. So we produced mortar test piece using grounded oyster shell powder under 0.5mm, which is a standard of fine aggregate, and reviewed strength properties according to water cement ratio. In our test, we used two kinds of oyster shell particles: below 0.6mm and 1.2~2.5mm. Water cement ratio is varied 40% to 100% and we found that flexural strength and compressive strength are decreased in higher water cement ratio.

• 자원리싸이클링
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• 제18권3호
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• pp.20-26
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• 2009

본 연구는 순환잔골재를 사용한 콘크리트의 굳지 않은 콘크리트 특성을 파악하고 순환골재 콘크리트의 품질관리 방안을 제시하고자 하였다. 이를 위하여 순환굵은골재 및 순환잔골재의 치환율을 조합하여 설계압축강도 30MPa의 콘크리트를 제작하였으며, 공기량 및 슬럼프를 측정하였다. 측정된 공기량 및 슬럼프 경시변화를 통하여 순환잔골재의 재료적 특성이 콘크리트의 물성에 미치는 영향을 파악하였으며, 골재의 흡수율 차에 따른 품질성능 저하를 고려할 수 있도록 현장 도착 슬럼프를 기준으로 전체 배합수를 일정하게 유지하는 품질관리 방안을 제시하도록 하였다. 본 실험에서는 골재 종류(천연, 순환)에 따른 표면수 보정을 통해 1시간 후 현장도착 슬럼프가 일정하게 유지될 수 있도록 콘크리트를 배합하였다. 순환골재의 사용에 따른 압축강도의 저하는 나타나지 않았다. 또한 표면수 보정을 통한 전체 배합수의 관리를 통하여 순환골재 콘크리트의 품질관리가 가능할 것으로 판단된다.

• KIEAE Journal
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• 제8권3호
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• pp.69-76
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• 2008

This is an experimental study on the maximum load value and structural behavior of reinforced concrete columns containing shells as a substitute fine aggregate of concrete, through making reinforced concrete test columns with shells. In this study, the main factors consist of the grain sizes and the percentage of substitution of shells to fine aggregate in two kinds of water cement ratio. The results of the study showed as followed. The maximum load value decreased with increased the rate of substitution about shells and as the grain size of shells became smaller, the load values of them were somewhat changed higher but it is important that we must consider absorption rate of shells sufficiently. If we have a proper water cement ratio in column productions containing the shells, we can meet the requirement of the percentage of substitution until 30%. The deflection and deformation properties of reinforced concrete columns with shells represented typical curves like that of normal reinforced concrete. But as the failture types, they are able to make some change without being out of the fundamental graph forms. After the analyzing structural behaviors and the properties of reinforced concrete test columns containing shells, the most excellent grain size of shells represented 3.0mm and less with taking uniformly, and the percentage of practicable substitution of them to fine aggregate was about 30%.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.127-128
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• 2014

The aim of this research is selecting an economical aggregate type for ultra-high strength concrete with 80 to 120 MPa of compressive strength. As the tests, the effect of water-to-binder ratios and types of aggregate on autogenous shrinkage of ultra-high strength concrete were evaluated. as the results of a series of tests performed, the slump flow was satisfied the target range of 600 ± 100 mm, and the concrete mixture with RLA showed higher elastic modulus than the other cases. For the autogenous shrinkage preventing performance, in the case of water-to-binder ratio of 15, and 20 %, the mixture with BA showed slightly improved autogenous shrinkage reducing effect than the mixture with RLA while the mixture with RLA showed better performance at 25 % of water-to-binder ratio. Therefore, based on the tests results of slump flow, elastic modulus, and autogenous shrinkage, the RLA is considered as a better aggregate type for this purpose.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.751-754
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• 2004

There are many factors that affect on the flowing properties of high flowing concrete(HFC), which are fluidity, compactibility, non-segregation ability and fillingability. And because the aggregate which is one of the factors occupies high volume in concrete, it has a much effect on the properties of high flowing concrete according to its size, quality and quantity etc. This is an experimental study to analyze the effect of admixture and volume of coarse aggregate in concrete on the flowing properties of high flowing concrete. For this purpose, the kinds of admixture are fly-ash and blast furnace slag. Also volume of coarse aggregate in concrete are 280, 290, 300, 310, 320 $(\ell/m^3)$. The test of flowablity properties is slump-flow, Air content, V-lot, L-Flow. According to test results, it was found that the compactibility of HFC is more superior to use blast furnace slag than other, and according .to kind of admixture, most compatible volume of coarse are different. Also when used blast furnace slag, the volume of coarse are increased than used fly-ash.