• 한국노년학
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• 제31권1호
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• pp.111-127
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• 2011

본 연구는 최근 급격한 복지확대를 경험하며 명실상부한 복지국가로 부상하고 있는 한국과 대만이 이전소득 체계를 통해 노인 빈곤을 효과적으로 감소시키고 있는지 비교론적 측면에서 분석함을 목적으로 한다. 분석대상은 서구 12개 복지국가와 동아시아의 한국과 대만이며, 가장 최근의 룩셈부르크 소득자료를 활용하여, 노후 소득의 혼합구조와 공적이전 및 사적이전 소득의 노인 빈곤율 및 빈곤갭 감소효과를 분석하였다. 연구결과는 크게 세 가지로 요약된다. 첫째, 복지국가 유형에 따라 정도의 차이는 있었지만 서구 복지국가의 노후 소득 구조는 공적이전을 중심으로 구성되어 있었으나, 한국과 대만의 경우 공적이전의 비중이 상대적으로 낮은 반면 사적이전과 근로에 의한 소득의 비중이 높아 전체적으로는 매우 혼합적인 구조를 가지고 있었다. 둘째, 빈곤선의 수준 및 복지국가 유형에 따라 상당한 편차가 존재함에도 불구하고, 서구 복지국가는 공적이전을 통해 노인 빈곤을 효과적으로 감소시켜 왔다. 셋째, 한국과 대만의 경우 최근의 급격한 복지확장에도 불구하고, 공적이전의 빈곤감소 효과는 여전히 제한적인 수준에 머물렀고, 사적이전의 빈곤감소 효과가 더 큰 것으로 나타났다. 이러한 일련의 국가 간 비교분석을 통하여, 근로소득의 비중이 30% 이상을 차지하는 한국의 노후소득 구조가 기형적인 것임을 지적하였으며, 공적연금이 성숙해 감에 따라 노후소득 구조와 공적이전의 기능이 어떻게 변화되어 가는 지에 대한 추가적인 연구의 필요성과 함께, 정책적 측면에서 현세대 노인에 대한 소득보장의 확대가 시급한 과제임을 논의하였다.

• 한국구조물진단유지관리공학회 논문집
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• 제28권1호
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• pp.24-31
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• 2024

기존 대부분의 3D 콘크리트 프린팅 연구는 모르타르를 재료로 활용하고 있다. 다만, 굵은 골재를 포함한 콘크리트에 비해 모르타르를 사용할 경우에는 높은 바인더 함량과 잔골재량으로 인하여 경제성이 저하될 수 밖에 없다. 따라서, 3D 프린팅 기술의 건설산업 적용 확대를 위해서는 굵은 골재를 사용한 콘크리트 3D 프린팅에 대한 연구가 요구된다. 본 연구에서는 굵은 골재가 포함된 3D 프린팅 용 콘크리트의 배합설계 프로세스를 제안하고자 하였다. 다양한 문헌연구 및 배합실험을 참고하여 3D 프린팅에 적합한 배합을 도출하였으며, 출력실험을 통하여 압출성을 검증하였다. 콘크리트 배합의 증점제(Viscosity modifying agent, VMA) 함량을 출력실험의 변수로 설정하였으며, 출력된 필라멘트의 치수 적합성, 골재분포도, 표면 품질을 평가하여 압출성능을 검증하였다. 실험결과, VMA의 함량이 높은 배합이 더 우수한 치수 적합성과 표면 품질을 보였으며, VMA 함량이 다름에도 불구하고 모든 배합에서 골재분포가 균등하게 나타났다. 실험결과를 바탕으로 굵은 골재가 포함된 콘크리트의 압출성을 향상 시킬 수 있는 배합설계 프로세스를 도출하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2004년도 학술.기술논문발표회
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• pp.109-112
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• 2004

Contemporary, architecture calls for a wide range of surface textures and treatments. A surface compatible with the architecture's design may vary from a glass-smooth finish to one requiring special sculptured ornamentation. These surfaces require many different types of form sheathing and lining. The purpose, of study development new design form and made elaborateness shape. Easy to used in field that architecture finish material not used expect effective reduce of working hours, personnel expenses, architecture finish material, cost, through this study, we have figured out the best mix proportion for durability and glossability of glossing exposure concrete.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.281-286
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• 2002

To study of binder and fine aggregate a lot of replacement fly-ash concrete, initial characteristics, standard environment of curing temperature $20^{\circ}C$, hot-weather environment of curing temperature $35^{\circ}C$, . Flesh concrete tested slump. air contest and Hardening concrete valuated setting period of form, day of age 1, 3, 5. 7, 10, 28 compression strength in sealing curing. Purpose of study is consultation materials in field that variety of fly-ash replacement concrete mix proportion comparison and valuation. (1) Experiment result age 28day compression strength more higher plan concrete then standard environment in curing temperature $20^{\circ}C$, , most strength F43 is hot-weather environment in curing temperature $35^{\circ}C$, replacement binder 25%, fine aggregate 15%. (2) Hot-weather environment replacement a mount of fly-ash is a same of plan concrete setting period of form. Age 28day compression strength replacement a mount of fly-ash more hot-weather concrete then plan concrete.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표논문집(II)
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• pp.275-280
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• 1998

In this study, to increase fluidity and resistance of segregation of materials, the effect of each of the materials, which have effects on high performance concrete from investigating the properties of strength and drying shrinkage of high performance concrete made by the basic mix proportion used fly-ash and ground granulated blast-furnace slag after hardening, has been checked. By the results of this experiment, fluidity on W/C=34% was satisfied within slump-flow 65$\pm$5cm and U-type self-compacting difference 5cm. On the properties of strength, high performance concrete produced compressive strength over 400kg/$\textrm{cm}^2$ in 28days when powder was replaced by 40% of fly-ash and 60% of ground granulated blast-furnace slag. And compressive strength was taken over 600kg/$\textrm{cm}^2$ equal to non-replacement in 91days. Also, the length change of concrete with the addition of fly-ash was smaller than that without it. Therefore, it may be effective on the decrease of drying shrinkage volume.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.245-248
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• 1999

In our standard specification, the specific provision of steel fiber pavement concrete didn't describe yet. The purpose of this study presents criteria of recycled aggregate steel fiber pavement concrete including standard crushed stone steel fiber pavement concrete. This study examined a lot of factors which influence consistency of SFRC(Steel Fibre Reinforced Concrete) including crush stone and recycled aggregate. According to this examination, this study decided optimum S/α and W which are essential to pavement concrete mix proportion. Come to the conclusion, this study is expected to effect economically in recycling of resources and bring to affirmative result in aspect of environment.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.147-150
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• 1999

Glossing Exposure Concrete is a high quality architectural concrete, i.e., appearance of natural stone and a marbling effect concrete to achieve high quality glassy reflective surface for outer wall of the building. In this study to obtain the conservation and durability of gloss of the "glossing exposure concrete" we developed a from practice and the best mix proportion and derived the optimistic removal time of form to bring out the durable glassy reflective surface and durable concrete. Hereby with the "glossing exposure concrete" obtained, we investigate the accelerate carbonation and accelerate durability test to evaluate the durability factor of this type of concrete.is type of concrete.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.641-646
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• 2001

Generally, when Fly-Ash was used as replacement material of cement in concrete, it might occur retardation of setting and hardening. So, it is unable to use a large amount of Fly-Ash as replacement for cement. However, if it is used as replacement material of fine aggregate in concrete, we can use a large amount of Fly-Ash and settle a problem of natural-aggregate exhaustion. Furthermore, engineering properties of High Volume Fly-Ash Concrete Is better than that of plain concrete But, the larger Fly-Ash is replaced, the more fluidity of High Volume Fly-Ash Concrete decrease, because porous organization of Fly-Ash adsorb water and Superplasticizer. In this study, after appending additional water to High Volume Fly-Ash Concrete in proportion to weight of Fly-Ash, we intend to find proper ratio which doesn't affect strength and satisfy fluidity As a result of this study, it was found that fluidity of mortar with 25~28 percentage of additional water was satisfied with fluidity of plain mortar, and compressive strength of that was similar to plain mortar's

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.281-286
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• 2001

The development of automobile, vessel, rail road, and machine industry leads increase of foundry production used as their components, which cause a by-product, waste foundry sand (WFS). The amount of the WFS produced in Korea is over 900,000 ton a year, but most WFS buries itself and only 5~6% WFS is recycled as a material in construction materials. In this study, WFS is used as a fine aggregate for concrete. Five types of concretes aimed at the specified strength of 240$\pm$10 kgf/$cm^{2}$ , air contents of 4.5$\pm$1% and slump of 12$\pm$1.5cm were mixed with washed coarse seashore sand(WFS) in which salt was removed and then optimum mix proportion of concrete was determined. Moreover, basic properties such as setting time, workability, bleeding and slump loss of the fresh concrete with WFS were tested and compared with those of the concrete mixed without WFS. In .addition, both compressive strength of hardened concrete at each ages and tensile strength of it at the age of 28 days were measured and discussed.

• 한국지열·수열에너지학회논문집
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• 제7권1호
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• pp.10-16
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• 2011

Performance of ground-source heat pumps (GSHPs) is mainly affected by ground heat exchangers which makes up more than 40% of construction cost. Exact construction and grout as backfill are important, because it is difficult to repair after being installed. As grout materials, bentonite grout material and cement material are used In this paper, thermal conductivity according to mix proportion of cement grout has been experimentally studied. Some variables were set to evaluate thermal conductivities according to change in cement content, unit water ratio, mass per volume of fresh mortar, and aggregate types. From the experimental analysis, high performance cement grout has been proposed.