• 한국농공학회:학술대회논문집
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• 한국농공학회 2002년도 학술발표회 발표논문집
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• pp.153-156
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• 2002

The purpose of this research was to evaluate on the properties of fresh and hardened high-performance concrete(HPC) incorporating high-reactivity metakaolin(HRM). Setting time, heat of hydration, compressive strength, resistance to chloride-ion penetration, and repeated freezing and thawing test were carried out in order to investigate the properties of fresh and hardened state concrete. The properties of the HRM concrete were also compared with those of the portland cement concrete and silica fume(SF) concrete. The laboratory test results indicate that HRM material can be used as a supplementary cementitious material to produce high-performance concrete.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2006년도 춘계학술논문 발표대회 제6권1호
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• pp.27-30
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• 2006

This study investigated influence of organic fiber type and contents on engineering properties of concrete. Test showed that increase of fiber contents decreased fluidity of fresh concrete and it was even worse in concrete adding cellulose fiber. It is decided that concrete containing more than proper level of fiber should be considered. In addition, concrete adding more fiber, nylon and cellulose, resulted in increase of air content but it was satisfied in aimed value. Bleeding capacity of concrete containing more fiber significantly declined and setting time of that was also slightly retarded. For the properties of strength, both compressive and tensile strength of fiber containing concrete were indicated at similar value to control concrete. However, it is clear that if those concrete containing fiber revised the value of increased air contents at fresh state, the strength value of that would be slightly increased.

• 한국식품영양학회지
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• 제37권1호
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• pp.40-47
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• 2024

Gastrodia elata has been used in traditional Chinese medicine for treating headaches, dizziness, and convulsive illness for centuries. G. elata has traditionally been processed by steaming or blanching to increase the content and quality of its main ingredients. This study aimed to identify changes in physicochemical properties and active ingredients of G. elata depending on the steaming time. Data of this study could be used to develop traditional medicine and health foods. No steaming was used as a control. Steaming time was 5, 10, 20, 30, 60, or 120 min. The drying yield according to the steaming time ranged from 20.2% to 22.9%, with the lowest drying yield at 120 min. As the steaming time increased, gastrodin content increased more than that in fresh G. elatadue to inhibition of β-glucosidase enzyme activity, 4-hydroxybenzyl alcohol condensation, and parishin decomposition. Steamed G. elatadid not show higher total polyphenols, total flavonoids, or ABTS radical scavenging activities than fresh G. elata even with an increase of steaming time. The steaming time to improve the quality of G. elata may varied depending on the size of G. elata. Thus, it is important to set the steaming time taking these characteristics into consideration.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표회 논문집(I)
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• pp.117-120
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• 1998

The objective of this study is to investigate the possibility for application of E.P-dust as both admixture and fillers for aggregates under various mixproportion, replacing method and the ratios of replacement. According to the experimental results, improvement of viscosity and reducing of segregation at fresh state and gain in strength at hardened state can be achieved by applying E.P-dust. It can be considered from the results that application of E.P-dust will be more efficient as fillers for aggregates than as binder

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.539-540
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• 2009

이 연구에서는 레올로지 제어를 이용하여 자기충전용 ECC(Engineered Cementitious Composite)를 개발하는데 그 목적을 두었으며, 레올로지 제어를 위하여 시멘트 페이스트에 대한 시멘트와 혼화제(감수제, 증점제)의 흡착정도를 평가하였고, 모르타르에 대하여 자기충전성과 유동특성을 평가하였다.

• 한국건설순환자원학회논문집
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• 제6권4호
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• pp.304-310
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• 2018

본 연구에서는 경량 기포 콘크리트의 부피 안정성을 확보하기 위해 소포를 저감시킬 수 있는 요소들을 레올로지 특성을 연계하여 분석하였다. 실험계획으로는 비빔시간, 물-결합재비, 증점제, 기포제, 폐지 첨가량에 대한 변화로 각 요인을 통해 실험하였다. 먼저 과도한 비빔과 기포제의 첨가량에 의해 발생한 다량은 기포는 슬러리 내에서 불안정한 상태로 존재하여 침하를 발생시킨다. 특히 기포제의 경우 계면활성제로써 물에 영향을 미치므로 배합 계획 시 물에 대한 질량비로 계획해야할 것으로 판단된다. 또한 레올로지 특성을 통해 경량 기포 콘크리트의 소성점도와 소포량이 반비례관계를 가진 것을 확인할 수 있었다. 따라서 본 연구의 결과는 경량 기포 콘크리트의 소포를 저감시킬 수 있는 요소들을 분석함으로써 경량 기포 콘크리트의 배합 조건에 대한 기초적인 자료를 제공될 것으로 판단된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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• pp.171-176
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• 1995

In recent years, Hith Performance Concrete has attracted world wide attention for its workability, strength and long-term durability. A field test was conducted to confirm the properties of high performance Concrete in situconditions. This paper describes the concrete materials, mix proportions, fresh state properties, some aspects of placability and qualty control results for field test. From the result, it was found that it is possible to produce High Performance Concrete with self-compactable and high strength.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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• pp.30-35
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• 1995

This paper presents fundamental experiment for the properties of high performance concrete in its fresh and hardened state made with ground granulated blast-furnace (GGBF) slag. The result is that the effect of decreasing xoncrete temperature is to the mixing ratio of GGBF slag, but it presents disadvantage in the slump loss phase. In addition to, we know that the splitting tensile strength, compressive strength and elastic modulus of concrete mixed with high fineness GGBF slag are increased at age 28days.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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• pp.318-320
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• 2013

The spherical bead manufactured by rapidly cooling process shows high density of 3.64g/㎤, high unit volume weight of 2.6kg/l, and high solid volume of 71%. When it applies to the grouter, it is possible to obtain even high fluidity with only a small amount. This study, focusing the grouter using a rapidly-cooled electric arc furnace oxidizing slag(RC-EAFS), deals with the properties of flow and setting time in fresh state, compressive strength and length variation at 1, 3, 7 and 28 curing day in hardened state. As the results, even though the grouter with RC-EAFS shows comparative low strength, it will be possible to development the competitive product due to the properties of increasing flow and low cost.

• Advances in concrete construction
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• 제7권2호
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• pp.97-105
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• 2019

In this paper, the workability and static stability were evaluated using a proposed test method. Workability and static stability represent a key property of self-compacting concrete (SCC) in fresh state. A number of standardized test methods were developed to assess these properties. However, no accelerated test method reliably predicts both workability and static stability of SCC. In the present work, a modified K-slump test method was developed to evaluate workability and static stability of SCC. In order to take implicit mixture variations of SCC constituents that can affect fresh SCC properties, a central composite design was adopted to highlight the effect of gravel to sand ratio (G/S), gravel 3/8 to gravel 8/15 ratio (G1/G2), water to cement ratio (W/C), marble powder to cement ratio (MP/C) and superplasticizer content (SP) on workability measured with slump and flow time (T50) tests and static stability measured with sieve stability test (Pi), segregation test index (SSI), Penetration test (Pd) and the proposed K-slump test (Km). The obtained results show that G/S ratio close to 1 and G1/G2 ratio close to 60% can be considered as optimal values to achieve a good workability while ensuring a sufficient static stability of SCC. Acceptable relationships were obtained between Slump flow, Pi, Pd and Km. Results show that the proposed K-slump test allow to assess both workability and static stability of fresh SCC mixtures.