• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.781-786
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• 2001

The Salt attack is one of the primary factors that cause the deterioration of durability in steel reinforced concrete structure. And to depreciate the deterioration from the Salt attack in concrete structure, pozzolanic materials are used widely in recent years. In this study, experiments about the resistance of chloride infiltration of concrete according to the replacement rations of Activated Hwangtoh and various pozzolanic materials(silica fume, fly ash, blast furnace slag and non Activated/Activated Hwangtoh) are performed and the results of this study were shown as follows; 1) As the replacement ratios of Activated Hwangtoh were getting higher, the strength of concrete was increased and in case of various pozzolanic materials, strength of Activated Hwangtoh in specimen was better than that of fly ash, blast furnace slag and non Activated Hwangtoh. 2) As the replacement ratios of Activated Hwangtoh were getting higher, the resistance of chloride infiltration of concrete was increased and in case of various pozzolanic materials, silica fume is better than any other pozzolanic materials and Activated Hwangtoh was better than that of fly ash, blast furnace slag and non Activated Hwangtoh.

• Advances in concrete construction
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• 제9권2호
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• pp.207-215
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• 2020

This paper describes the experimental studies carried out to determine the properties of fresh and hardened concrete with Recycled Plastic Waste (RPW) as a partial replacement material for fine aggregates. In the experimental study, RPW was used for replacing river sand and manufactured sand (M sand) aggregates in concrete. The replacement level of fine aggregates was ranging from 5% to 20% by volume with an increment of 5%. M40 grade of concrete with water cement ratio of 0.40 was used in this study. Two different types of RPW were used, and they are (i) un-activated RPW and (ii) activated RPW. The activated RPW was obtained by alkali activation of un-activated RPW using NaOH solution. The hardened properties of the concrete determined were dry density, compressive strength, split tensile strength, flexural strength and ultrasonic pulse velocity (UPV). The properties of the concrete with river sand, M sand, activated RPW and un-activated RPW were compared and inferences were drawn. The effect of activation using NaOH solution was investigated using FT-IR study. The micro structural examination of hardened concrete was carried out using Scanning Electron Microscopy (SEM). The test results show that the strength of concrete with activated RPW was more than that of un-activated RPW. From the results, it is evident that it is feasible to use 5% un-activated RPW and 15% activated RPW as fine aggregates for making concrete without affecting the strength properties.

• 한국농공학회논문집
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• 제51권4호
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• pp.21-27
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• 2009

This study was performed to evaluate the physical and mechanical properties of porous concrete using waste activated carbon. Material used were ordinary portland cement, recycled coarse aggregate, waste activated carbon and superplasticizer. The replacement ratios of waste activated carbon were 0,1,2,3,4,5,6,7,8,9, and 10 %. The void ratio was decreased and ultrasonic pulse velocity was increased with increasing the waste activated carbon powder, respectively. The compressive strength and flexural strength of porous concrete using waste activated carbon powder were in the range of 8.21${\sim1}$6.58 MPa and 1.69${\sim1}$3.68 MPa, respectively. The pH degree of porous concrete in 1day and 77days were shown in 12.50${\sim1}$12.63 and 10.21${\sim1}$10.70, respectively. Accordingly, waste activated carbon can be used for porous concrete material.

• Geomechanics and Engineering
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• 제33권1호
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• pp.19-27
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• 2023

A series of experiments were performed to evaluate the effects of activated carbon on the compressive strength and air content of Portland Cement Concrete (PCC). Activated carbon/PCC composites were prepared by mixing concrete components with commercial activated carbon granules with weight fractions of 0, 0.5%, 1%, and 2% to cement. All PCC specimens were then tested for compressive strength on 7, 14, 21, and 28 days. The experimental results showed that adding 0.5% of activated carbon increased the compressive strength significantly over the curing periods compared to the normal PCC without activated carbon. For the specimens has 0.5% activated carbon, the 7, 14, 21, and 28-day compressive strengths increased by 28.7%, 22.2%, 26.8%, and 22.9%, respectively. However, adding excessive amounts of more than 1% activated carbon had a minimal effect on the compressive strength or even decreased it, which agrees with other studies. Regarding the air contents of the mixtures, adding activated carbon decreased the air content from 3.6% to around 1.5%. The surface morphologies of fine aggregates and activated carbon particles were compared using a novel image processing technique. The results indicated that the surface of activated carbon significantly differs from that of aggregates.

• 한국농공학회논문집
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• 제51권1호
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• pp.21-26
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• 2009

This study was performed to evaluate the physical and mechanical properties of concrete using waste activated carbon. Materials used were ordinary portlant cement, crushed coarse aggregate, natural fine aggregate, waste activated carbon, and superplasticizer. The substitution ratios of waste activated carbon were 0,1,2,3,4,5,6,7,8,9 and 10%. The unit weight was decreased and water absorption ratio was increased with increasing the waste activated carbon content, respectively. When the substitution ratio of waste activated carbon was 3%, compressive strength, flexural strength and dynamic modulus of elastisity were more higher than that of the ordinary portland cement (OPC), and it was decreased with increasing the waste activated carbon content, respectively. The most effective contents of waste activated carbon was 2% in performance and 4% in practical use Accordingly, waste activated carbon can be used for concrete material.

• 콘크리트학회논문집
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• 제22권5호
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• pp.685-694
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• 2010

지금까지 환경 친화적 재료로서 황토에 관한 연구는 포틀랜드 시멘트를 부분적 대체하거나, 완전 대체하는 연구로 진행되어 왔다. 기존의 대부분의 연구에서는 압축강도, 건조수축, 크리프 등 황토 콘크리트의 역학적 성질에 초점이 맞춰졌다. 이 연구에서는 황토 콘크리트로 제작된 보 실험체의 전단강도를 실험하였다. 또한 황토 콘크리트에 정착된 인장 철근의 부착강도를 실험하였다. 이번 실험에서 시멘트를 20% 대체하는 활성 황토와 시멘트를 100% 대체하는 활성 황토를 사용한 콘크리트가 사용되었다. 실험 결과, 시멘트 20% 대체 활성 황토와 무시멘트 활성 황토 콘크리트 보의 전단 강도는 일반 포틀랜드 시멘트 콘크리트 보와 동등하였다. 반면에, 무시멘트 활성 황토 콘크리트의 부착 강도는 일반 포틀랜드 시멘트 콘크리트보다 작았다.

• International Journal of Concrete Structures and Materials
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• 제9권2호
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• pp.145-158
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• 2015

The consequence of sulfate attack on geopolymer concrete, made from an alkali activated natural pozzolan (AANP) has been studied in this paper. Changes in the compressive strength, expansion and capillary water absorption of specimens have been investigated combined with phases determination by means of X-ray diffraction. At the end of present investigation which was to evaluate the performance of natural alumina silica based geopolymer concrete in sodium and magnesium sulfate solution, the loss of compressive strength and percentage of expansion of AANP concrete was recorded up to 19.4 % and 0.074, respectively.

• International Journal of Concrete Structures and Materials
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• 제5권2호
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• pp.125-131
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• 2011

Five all-lightweight alkali-activated (AA) slag concrete mixes were tested according to the variation of water content to examine the significance and limitation on the development of cementless structural concrete using lightweight aggregates. The compressive strength development rate and shrinkage strain measured from the concrete specimens were compared with empirical models proposed by ACI 209 and EC 2 for portland cement normal weight concrete. Splitting tensile strength, and moduli of elasticity and rupture were recorded and compared with design equations specified in ACI 318-08 or EC 2, and a database compiled from the present study for ordinary portland cement (OPC) lightweight concrete, wherever possible. Test results showed that the slump loss of lightweight AA slag concrete decreased with the increase of water content. In addition, the compressive strength development and different mechanical properties of lightweight AA slag concrete were comparable with those of OPC lightweight concrete and conservative comparing with predictions obtained from code provisions. Therefore, it can be proposed that the lightweight AA slag concrete is practically applicable as an environmental-friendly structural concrete.

• 콘크리트학회논문집
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• 제22권4호
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• pp.567-574
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• 2010

지금까지 환경 친화적 재료로서 황토에 관한 연구는 포틀랜드 시멘트를 부분적 대체하거나, 완전 대체하는 연구로 진행되어 왔다. 기존의 대부분의 연구에서는 압축강도, 건조수축, 크리프 등 황토 콘크리트의 역학적 성질에 초점이 맞춰졌다. 이 연구에서는 황토 콘크리트로 제작된 보 실험체의 휨 성능을 실험하였다. 이번 실험에서는 시멘트를 20% 대체하는 활성 황토를 사용한 콘크리트와 시멘트를 100% 대체하는 활성 황토 콘크리트가 사용되었다. 단순보 실험은 2점 정적 재하 하중으로 실험하였다. 휨 강도, 균열 모멘트, 처짐, 연성도 등의 결과를 일반 포틀랜드 시멘트 콘크리트로 제작된 보의 실험 결과와 비교하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 추계 학술논문 발표대회
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• pp.105-106
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• 2011

The present tests examined the resistance to freezing and thawing of alkail-activated (AA) slag concrete having compressive strength between 30~56 MPa. To enhance the compressive strength and resistance to freezing and thawing of AA slag concrete, Na ions were used for an activator. Test results revealed that the resistance to freezing and thawing of AA slag concrete is comparable to that of cement concrete when compressive strength is more than 50 MPa.