• Title/Summary/Keyword: grass concrete

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Toughness and microscopic pore structure analysis of pasture fiber recycled concrete

  • Hailong Wang;Lei Wang;Hong Yang
    • Advances in concrete construction
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    • v.16 no.3
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    • pp.141-153
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    • 2023
  • In order to develop and take full advantage of pasture fiber and waste concrete, this article studied how different amounts of pasture fiber influenced the toughness and pore structure of concrete with different replacement rates of recycled fine aggregate. Pasture fiber recycled concrete constitutive equations were established under idealized stiffness and toughness damage rate, based on fracture energy and damage mechanics theories. The relationship between pore structure and toughness was studied utilizing nuclear magnetic resonance and fractal theory. The toughness of text groups (0% (JZ), 10% (ZS10), 20% (ZS20)) first increased and then decreased with increasing amounts of pasture fiber, based on the damage rate of toughness. The toughness of concrete samples with recycled fine aggregate and pasture fiber is negatively correlated to the fractal dimension of small and medium-sized pores with a pore size of 0-500 nm. At a replacement rate of 10% of the recycled fine aggregate, the fractal dimension of the air voids (r: 500-9000 nm, i.e., Lg(r) ∈ [2.7, 3.9]) shows a gradual decrease with the increase of grass fiber dosage, indicating that with such a replacement rate of the recycled fine aggregate, the increase of pasture fiber can reduce the complexity of the pore structure of the air voids (500-9000 nm).

The Properties of Concrete containing Waste-glass Powder (혼화재로서 폐유리 미분말을 사용한 콘크리트의 특성 평가)

  • Choi, Sung-Woo;Ryu, Deug-Hyun;Kim, Jun-Hyoung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2017.05a
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    • pp.222-223
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    • 2017
  • In the automotive industry, such as scrap metal and plastic scrap process is being recycled. Although the glass beads are used as road paving or other additives and processing crushing, recycling is known that there are limits. The utilization of waste glass was evaluated as a concrete admixture by using powder characteristics and chemical composition of the glass. As a result of using waste-glass powder as an admixture, it is difficult to expect the pozzolanic effect, but it is found that it can increase the fluidity of concrete and ensure the durability performance in the appropriate amount range.

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An Experimental Study of Green Roofs on Indoor Temperature Reduction (옥상녹화의 건물 내 온도 저감 효과에 대한 실험적 연구)

  • Kang, Da Won;Choi, Hui Dong;Seo, Yong Won
    • Proceedings of the Korea Water Resources Association Conference
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    • 2021.06a
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    • pp.157-157
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    • 2021
  • 2015년 파리에서 체결된 파리협정은 1850년 대비 2100년까지의 지구 평균기온 상승을 1.5℃ 이내로 제한하기 위해 5년마다 참여국에 상향된 온실가스 배출 감축 목표를 제출하게 하고, 탄소 배출 및 온도상승 저감 목표 달성을 위해 도시 내 그린인프라를 적극적으로 도입하는 등 국제사회 공동의 종합적인 이행을 예정하고 있다. 그린인프라의 유형 중 하나인 옥상녹화(Green Roof)는 기후변화 적응을 위한 도시 인프라 구축 방법의 하나로 국내에서도 많은 각광을 받고 있다. 옥상녹화(Green Roof)는 도시의 불투수층인 지붕 면적을 모두 혹은 일부 식생으로 덮어 표면층에 추가의 투수층을 조성하는 것을 지칭한다. 옥상녹화의 경우 별도의 토지면적 확보가 필요하지 않고 기존의 시설물에 추가적인 설치가 가능해 여분의 토지가 부족한 도심지의 녹지 확보를 위한 친환경적인 그린인프라로 각광받고 있다. 현재까지 옥상녹화(Green Roof) 관련 국내 연구 현황은 '옥상 녹화의 공법'을 다룬 비율이 높고 실증적인 결과를 가진 선행연구가 거의 없다. 따라서 본 연구는 동일한 조건하에 4개의 실험동을 설치하고 동질성 검사를 한 후 옥상에 설치된 재료[일반 콘크리트(Bare Concrete), 고반사 도장(High Reflective Paint), 사사(Short Bamboo), 잔디(Grass)]에 따른 건물 내 온도 변화 저감효과에 대한 분석을 수행하였다. 2020년 8월 17일부터 22일까지 측정된 지붕 표면 평균 최고온도 모니터링 결과를 일반 콘크리트 지붕과 비교했을 때. 고반사 도장 지붕의 경우 8.26℃, 옥상녹화(사사, short bamboo) 지붕의 경우 7.21℃, 옥상녹화(잔디, grass)의 경우 10.8℃ 낮은 것으로 측정되었다. 또한 실내 천정 표면 평균 온도의 경우 콘크리트 지붕과 비교하여 고반사 도장 지붕은 6.46℃, 옥상녹화(사사, short bamboo) 지붕은 13.52℃, 옥상녹화(잔디, grass)는 13.3℃ 낮은 것으로 나타났다. 본 연구결과는 옥상녹화의 온도저감 효과를 정량적으로 제시하고 있어, 향후 기후변화 대응 및 적응 전략적 수립에 기여할 수 있을 것으로 판단된다.

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The effects of adjective meaning on response to color: A test using Stroop task (형용사의 의미가 색 구별에 미치는 영향: 스트룹 과제를 통한 검증)

  • Hong, Seongkyun;Kim, Kyungho;Li, Hyung-Chul O.;Kim, ShinWoo
    • Korean Journal of Cognitive Science
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    • v.28 no.1
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    • pp.27-42
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    • 2017
  • Stroop effect(Stroop, 1935) is a reliable paradigm which has been used in various psychological research. Although classic Stroop experiment used color and color name for experimental stimuli, subsequent research reported that a color(e.g. green) and an object(e.g. grass) which displays a typical color show similar effects depending on color-object congruency(Klein, 1964). Because past research that used Stroop effect to investigate semantic representation tested association between concrete object and color, they predominantly used concrete nouns and their corresponding color names as stimuli(e.g. Dalrymple-Alford, 1968, 1972; Klein, 1964). Recently, Sherman and Clore(2009) reported that response time to white or black words is affected by moral value of words (e.g., honesty, crime) even when the words do not have specific referents. Based on this result, we tested association between thermesthesia-related adjectives(e.g., 따스한, 냉정한) and color(warm color, cold color) using Stroop task. The results showed that subjects were faster in their response to color when adjective-color was congruent than when incongruent, and there was an interaction between color and meaning of adjectives. The Stroop effect in this research is unique because, contrary to previous research that used concrete nouns, the effect was obtained even with abstract adjectives which do not have specific referents. In addition, unlike Sherman and Clore(2009) that used achromatic color, our results show that Stroop effect obtains between abstract adjectives and chromatic color.

Planting Properties of Porous Polymer Block Using Recycled Coarse Aggregates (재생굵은골재를 사용한 다공성 폴리머 블록의 식생 특성)

  • Sung, Chan-Yong;Kim, Young-Ik
    • Korean Journal of Agricultural Science
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    • v.37 no.1
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    • pp.87-96
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    • 2010
  • This study was performed to evaluate the planting properties of herbaceous plant and cool-season grass in porous polymer blocks that were manufactured by using recycled coarse aggregates and unsaturated polyester resin to develop environmentally friendly planting blocks. Unsaturated polyester resin, natural and recycled coarse aggregates and $CaCO_3$ were used. The mix proportions were determined to satisfy the requirement for the workability and slump according to aggregate sizes(5-10 and 5-20mm). Tests for the void ratio and compressive strength of porous polymer concrete were performed at curing age 7 days. Also, porous polymer block using recycled coarse aggregates were applied to kinds of plants such as tall fescue, Perennial ryegrass, Lesedeza and Alfalfa. After seed, initial germination, germination ratio, cover view and growth length for planting blocks were estimated by various methods.

Psychological Character Analysis of Pavement Materials (포장재료의 심리적 특성 분석)

  • Kim Dae-Hyun
    • Journal of the Korean Institute of Landscape Architecture
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    • v.32 no.5
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    • pp.43-51
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    • 2004
  • Recently, the importance of choosing correct pavement materials has been increasing in urban spaces and streets. Much research regarding the pavement theory and construction method have been conducted, but analysis in terms of human psychological character has not yet been performed. The purpose of this study is to investigate the psychological characters to 12 pavement materials, that are commonly used in our urban spaces and streets. The results of the psychological character for each pavement material can be summarized as follows: 1. The psychological characters to each pavement material were as follows: ① Clay embodies a natural, traditional, soft and intimate psychological character; ② Pebble stone has a natural, hard, cool and intimate psychological character; ③ Turf grass incorporates an intimate and soft psychological character; ④ Ceramic brick has an artificial and hard psychological character; ⑤ Tile pavement has a modern, artificial, hard and cool psychological character; ⑥ Water permeable concrete has a modern and artificial psychological character; ⑦ Flag stone has a natural psychological character; ⑧ Granite has a modern and artificial psychological character; ⑨ Portland concrete has an artificial and hard psychological character; ⑩ Small compacted brick has an artificial, dynamic and modern psychological character; ⑪ Wood block pavement has a natural and traditional psychological character; ⑫ Asphalt concrete pavement has a modern, hard and artificial character. 2. On the results of the cluster analysis regarding psychological indexes for 12 pavement materials, pavement materials were categorized in 3 clusters. Among them, one cluster was mainly used as the most popular pavement material in our urban spaces and streets. From this point of view, psychological character for pavement material in our urban spaces and streets was not as various as we expected. 3. In conclusion, the proper selection of pavement materials was very important and the factors affecting the human psychological character should be considered in the design of urban spaces and streets.

Effect of Autoclaved Lightweight Concrete on the Growth of Zoysia Japonica Steud (경량기포 콘크리트 부산물 시용이 잔디의 생육에 미치는 영향)

  • Yuk, Chang-Soo
    • Korean Journal of Soil Science and Fertilizer
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    • v.31 no.4
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    • pp.368-372
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    • 1998
  • A field assay was conducted to study whether the by-product of Autoclaved Lightweight Concrete(ALC) could be used as a silicate fertilizer for Korean Zoysiagrass. ALC application rates (0, 2.0, 4.0, 6.0 and $8.0Mg\;ha^{-1}$) were investigated for their effects on growth status, mineral nutrient concentrations, yield of fresh and dry matter of lawn grass and soil properties after experiments. The number of stolon and length of stolon at 180 day after Zoysiagrass transplanting were increased in the treatemnt of $2.0{\sim}6.0Mg\;ha^{-1}$ of ALC application, but those of $8.0Mg\;ha^{-1}$ of ALC plot were deceased with excess of ALC. The fresh weight and dry matter at harvesting time of lawn grass treated with $6.0Mg\;ha^{-1}$ of ALC was heavier than those of other ALC plots. There were statistically significant between the number of stolon and length of stolon remarkably. Mineral nutrient contents such as Si and Ca in Zoysiagrass were increased by higher ALC application, while T-N, available P and K were no difference with application lavel of ALC. Soil pH and Si contents in soil after experiment were increased by ALC application remarkably.

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Field survey of slope hazards mitigation method in Muju-Jangsu area (무주-장수지역에 적용된 급경사지재해 대응공법 현장조사)

  • Song, Young-Suk;Cho, Yong-Chan;Chae, Byung-Gon;Kim, Kyung-Su;Kim, Man-Il
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.03a
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    • pp.1053-1059
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    • 2009
  • In this study, slope hazards mitigation methods for a natural terrain are systematically classified to survey the mitigation methods and develop a data base system. Also, field survey sheets which can be recorded the features of mitigation methods installed in the natural slope are developed. The slope hazards mitigation methods in the natural slope are classified as hillside part method and valley part method. The slope part sheet and the valley part sheet are also drawn up for field survey. As the result of the filed survey of mitigation methods about 50 points in Muju and Jangsu area, grass painting and slope covering methods are dominant in case of slopes part. In case of valley part, slit dam, concrete check dam and slope foot barrier are applied simultaneously.

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The Politics and Governance of 'Maeul' Community Archives in South Korea (마을공동체 아카이브의 거버넌스 모델 연구)

  • Lee, Kyong Rae
    • The Korean Journal of Archival Studies
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    • no.45
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    • pp.51-82
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    • 2015
  • Maeul-making, which is to restore inherent characteristics of maeul as a living community has been proceeded by local communities themselves since the 1990s when political democracy and local government in Korean society has been progressed in full-scale. Although New Maeul Movement has been done in the 1970s before and after, it is different from maeul-making because it was focused mainly on improving physical environments of rural communities and initiated by government. The development of maeul community archives in Korea has been related closely to such a maeul-making since the 1990s. Maeul-based community archives, maeul community archives had been begun to build as part of maeul-making and grass-root movement by the 2000s. Initiated by self-motivated communities, maeul community archives were carried out through cooperations between civic activists and residents in maeul communities and voluntary professional archivists from outside. Although records about the maeul community has been collected by mainstream cultural institutions such as public archives, museum, local historical association, and local cultural center, it was at this time to collect records of the maeul community by self-motivated local residents. This tendency of 'independent' maeul community archives, however, is currently entering upon a new phase with the city of Seoul's project (2012) to support making a maeul community, that is, the governance phase based on private-government partnership. At this point of time, it is important for maeul community archives to be built on privately-led governance model that guarantees their autonomy and at the same time bring government's knowhow and supports into them, as opposed to the way captured or driven unilaterally by government. This article explores the growth of maeul community archives and collections in Korean society through a range of self-motivated bodies; the interaction with government; and as a result of those interactions, the creation of maeul community archives based on governance. To introduce and explicate the motivations behind maeul archiving endeavors, this article will first sketch something of the historical, social, and political context in which 'maeul' communities have arisen, collapsed, and restored. It will then examine in more detail some specific examples of maeul community archives as grass-root movement of maeul community. The third section will attempt to identify the governance model of maeul community archives under the auspices of the city of Seoul and its limitations. Finally through these activities, it will suggest the ways in which maeul community archives commit themselves to their duty of grass-root movement of community and at the same time, secure sustainability, that is, concrete ways of privately initiated governance model.

Deterioration and Conservation Treatment of the Three Storied Stone Pagoda in Seoak-ri, Gyeongju (경주 서악리 삼층석탑의 훼손상태 및 보존처리)

  • Lee, Myeong-Seong;Jeong, Min-Ho;Jung, Young-Dong;Lee, Chan-Hee
    • Journal of Conservation Science
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    • v.18 s.18
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    • pp.63-74
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    • 2006
  • All rock materials of the three storied stone pagoda in Seoakri were composed of light gray alkali granite with medium grained and developed with small mialolitic cavities. This stone pagoda is preserving almost archetype except the head part because there was repair work already. But, foundation, basement and roof rocks are serious state by microbial invasion such as lichens. Because there are tree and grass that cause direct effect to stone pagoda surrounding. Therefore, conservation treatment executed the primary dry cleaning and secondary wet cleaning treatment. Stone surface is partly not removed well such as lichens which part removed using cleansing device that use high temperature steam. Some treated part concrete and epoxy resin remove and retreatment with mixing talc and alkali granite powder to epoxy resin. Did color matching at mixing process of epoxy resin and fillers to properties with set the feel of a material. Also, drainage ditched to minimize inflow of rainwater fall from slope that is on the east of stone pagoda, tree and grass in stone pagoda surrounding wished to do remove and control occurrence of lichens hereafter minimizing moisture conteats.

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