• 한국농공학회지
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• 제42권
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• pp.78-84
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• 2000

Permeable polymer concrete can be applied to roads, sidewalks, river embankment, drain pipes, conduits, retaining walls, yards, parking lots, plazas, interlocking blocks, etc. This study is to explore a possibility of utilizing industrial by-products, a blast furnace slag and a fly ash, as fillers for permeable polymer concrete. Different mixing proportions are tried to find an optimum mixing proportion of permeable polymer concrete. The tests are carried out at 20$\pm$1$^{\circ}C$ and 60$\pm$2$^{\circ}C$ relative humidity. At 7 days of curing, compressive, flexural and splitting tensile strengths and water permeability ranged between 239~285kgf/$\textrm{cm}^2$, 107~133kgf/$\textrm{cm}^2$, 37~46kgf/$\textrm{cm}^2$ and 4.612~5.913$\ell$/$\textrm{cm}^2$/h, respectively. It is concluded that the blast furnace slag and fly ash can be used in permeable polymer concrete.

• 한국건축시공학회지
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• 제12권5호
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• pp.468-477
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• 2012

This study aimed to mix and test mortar incorporating activated Hwangtoh to improve the Hwangtoh brick bond strength of brick structures. To do this, the bond strength correlation of mortar was analyzed by means of materials and experiment factors and levels, and the optimum conditions were suggested after analyzing the physical properties of brick and the mix ratio of mortar and additive. Furthermore, the compressive strength and bond strength were found to be in inverse proportion, and in terms of the materials and mixing level, W/C ratio, substitution ratio of activated Hwangtoh, and fine aggregate grading were shown to have a considerable influence on the strength. In conclusion, the optimum mixing conditions to improve the bond strength are found to set W/C ratio at 65% and replacmenet ratio of activated Hwangtoh at 10%.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.150-151
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• 2014

Although there has been many research regarding improving anti-shock performance and durability of concrete using fiber-reinforcement, there are still drawback on workability with interruption of fibers such as fiber-ball. Hence to solve this problem, in previous research, the optimum combination of fibers to improve workability of HPFRCC. In this research, based on the result of previous research, to improve the workability further, various fine aggregate contents is evaluated on workability, and the most appropriate mixing proportion is suggested.

• 월간산업보건
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• 통권8호
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• pp.4-30
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• 1988

Examination of working environments was conducted to get more detailed data about harmful working environments and to make a contribution to more effective management. Study was carried out on 722 factories located in Taegu city and eight counties in Kyungpook Province, Korea, for a period of one year, from February 1 to December 30, 1986. The total number and proportion of workers exposed to harmful material was 37,697, 45.2% among 83,368 workers. The results according to exposed material were as follows: 1. In the case of noise, proportion of exceeding the 8-hour TLV was 59%, Included were nail-cutting in assembly metal manufacturing industry and weaving process in textile. 2. Dust in mill process of coal manufacturing industries exceeded the TLV of second class of dust at all parts and exceeded the TLV at 6% as a whole.: 3. The fields of industry lower than 70 lux of illumination were storage equipment of food, auto-winder of textile, painting of wood wares and coal mixing, and 44% of all cases was lower than standard. 4. As a result of temperature index investigation(WBGT), about 12% of all sujects exceeded limit value. Included parts were rolling machine and reducing room. 5. In the case of organic solvents, TLV was exceeded at about 8%, The parts exceeded TLV according to materials belonged to this category were as follows. 1) Toluene: adhesive work in assembly metal manufacturing 2) Xylene: printing and paint mixing in chemical manufacturing 3) Methyl ethytl ketone: paint mixing in all parts examined and coating machine partially in chemical manufacturing 4) Methyl isobutyl ketone: printing in chemical manufacturing 5) Acetone: vapor polishing in assembly metal manufacturing 6. Among specified chemical materials, the concentration of HC1 in the air in metal assembly manufacturing factory exceeded TLV. in one of three assembly metal manufacturing examined. Others, such as benzene, acetic acid, formic acid, sodium hydroxide, formalin, ammonia, copper, chromate etc. were lower than TLV in its indoor atmospheric concentration. As a whole, the proportion of exceeding TLV was about 0.8% 7. The concentrations of inorganic lead were lower than TLV in all parts examined. The results of this investigation show the fact that current management of working environments is not satisfactory, and so more active management is needed.

• 한국작물학회지
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• 제51권3호
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• pp.187-190
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• 2006

저 마약형 대마 품종이 육성되지 않았을 경우 그 대안으로서 섬유용 대마의 THC 함량을 낮추기 위해 저 마약형 도입 유전자원중 경장은 작지만 개화기가 재래종과 비슷한 IH3 과 재래종 종자를 1:1, 2:1, 3:1로 혼합하여 채종시험을 실시하고 각 혼합비율별로 채종한 종자를 섬유용으로 재배하여 종실용 및 섬유용 대마 생육특성과 수량, 그리고 cannabinoid 함량분포를 검정한 결과를 요약하면 다음과 같다. 채종시험에서 IH3 의 비율이 클수록 천립중은 무거웠으나 종실수량은 100 kg/10a 내외로 차이가 없었다. 혼합비율별로 집단 채종한 종자를 섬유용으로 재배하였을 때 섬유수량은 $193{\sim}198kg/10a$로 비슷하였으나 THC 함량은 종자 IH3 혼합비율이 클수록 낮아져 3:1 에서는 0.39%이었다. THC 및 CBD 함량분포에서도 IH3 혼합비율이 높을수록 마약형 및 중간형 비율이 낮아졌고 저 마약형 비율은 증가하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.549-554
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• 2002

In Powder System, SCC demands high dosage of superplasticizer and a lage amout of powder for suitable fluidity and viscosity. Okamura's method of most representative mixing design method in SCC of Powder-System is unfavorable economically because of using a large amount of powder. In addition, many ready-mixed concrete plants do not use his mix design method and procedure due to complexity for practical application. Therefore, Nan Su proposed more simple mix design method than Okamura's. It had an advantage in simplicity in practical application and required a smaller amount of powders compared with Okamura's method. This paper proposed an optimal mixture proportion of SCC with consideration of Nan Su's method. The new and modified mix design method required a smaller amount of powder than that of Nan Su's. To check the properties of SCC, considered with the requirements specified by the Japanese Society of Civil Engineering.(JSCE)

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.533-536
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• 2003

The objective of in this study makes investigation into the characteristics of antiwashout underwater concrete as to mix proportion, casting and curing water through experimental researches. in this study, sea sand is blended with river sand, crushed sand is blended with river sand and sea sand as to investigate the quality change and characteristics of antiwashout underwater concrete with variation of blend ratio of sea sand and crushed sand(0, 20, 40, 60, 80, 100%). Higher compressive strength is measured following the order of river sand, sea sand, crushed sand regardless of age and casting condition. Except for case of using river sand, blended ratio of 40% is appeared on most compressive strength.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.385-390
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• 1997

In the mixing proportion of high flowing concrete we have to use quantity of power such as cement and superplasticizer, and increase the proportion of fine aggregate more than that of plain concrete to increase flowability and segregation resistance. Therefore, the fresh state of high flowing concrete is largely affected by superplasticizer and change of grade the percentage of surface water. This study aims at development of self-filling up high flowing concrete without compaction, in case of using the fine aggregate of standard grade range, by examination on the influence of fresh state of high flowing concrete, and by understanding influence on various fluidity such as flowability, reinforcement passibility, fillingability, segregation resistance.

• 한국농공학회지
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• 제43권3호
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• pp.66-76
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• 2001

Recently the use of the antiwashout underwater concrete with the antiwashout admixture is increased considerably. Antiwashout underwater concrete is quite different in concept from conventional underwater concrete. By mixing an antiwashout admixture with concrete, the viscosity of the concrete is increased and its resistance to segregation under the washing action of water is enhanced. The aims of this research is statistically evaluated to mix proportion factor of antiwashout underwater concrete. Experiment was performed to analyze the influence variables(cement, water, and antiwashout admixture) on fundamental characteristics of antiwashout underwater concrete. The influence variables can be considered for use in a wide range of underwater work where their have statistically significant effect on the characteristics(fluidity, filling ability, resistance to washout, etc.) of antiwashout underwater concrete.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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• pp.111-112
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• 2016

Waterproofing methods for applying to roof-top in the building are various, but it is not enough to development, which are simplified and low-cost method for old building. Especially, these buildings have not only a low insulation, but a disadvantage for energy. A floating floor method is necessary for this. This study performs an experimentt about bonding capacity of complex panel for waterproofing and heat insulation. The bond strength experiment is based on KS F 4716, and it is considered by bond mix proportion about panel and slab.