• Title/Summary/Keyword: Concrete properties

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The Study on the main viewpoints chosen for the landscape simulation evaluation (경관시뮬레이션 평가를 위한 주요 조망점 선정에 관한 연구)

  • Lee, Im jung;Choi, Joo youn
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.11
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    • pp.7534-7540
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    • 2015
  • In this paper, we set up a vista point overlooking the focus of new research center placed on the existing research literature and point to the selection of books, reports or studies actually suggested focusing on topics such as for landscape simulation evaluation. To re-organize and classify a number of items were presented to spill the evaluation items of this view point selection via the SPSS Statistics. Evaluation items 16 through a professional survey to establish a concrete and systematic plan with selected research results leaked technical characteristics of the view that detailed questions to the factors of technical characteristics and population-specific comparisons through factor analysis in the first, landscapes simulation The views were set out. Second, if you set 16 classified by type of view that considering a similar nature or characteristics depending on the properties of the view that publicity, overlooking castle, the castle was divided into three types of places. Third, the views point for the public good are three items, vista point at which the gender perspective has six items that gender point of view places is set to seven items, was set up to view the most appropriate place to point gender. These results provide a framework for analysis and future system reliability and landscape simulation evaluation study is expected to be used as reference material.

Durability Characteristics of Ternary Cement Matrix Using Ferronickel Slag According to the Alkali-Activators (알칼리 활성화제 종류별 페로니켈슬래그를 사용한 3성분계 시멘트 경화체의 내구특성)

  • Cho, Won-Jung;Park, Eon-Sang;Jung, Ho-Seop;Ann, Ki-Yong
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.8 no.2
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    • pp.190-197
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    • 2020
  • This paper evaluates the mechanical properties and durability of cement matrix blended with mineral admixtures and ferronickel slag(FNS) powder which is an industrial b y-product during ferronickel smelting process. The hydration heat, pore structure, compressive strength, length change, rapid chloride penetration test(RCPT), and freezing and thawing resistance of ternary blended cement matrix were investigated and compared with ordinary portland cement matrix. The result showed that the compressive strength of ternary blended cement matrix using ferronickel slag powder and mineral mixture was low in strength compared to the reference concrete, but recovered to a certain extent by using alkali activator. Length change of cement mortar using FNS powder have shown less shrinkage occurs than the reference specimen. In addition, irrespective of using the alkali-activators, all ternary mix are indicative of the 'very low' range for chloride ion penetrability according to the ASTM C 1202, and the freeze-thaw resistance also showed excellent results.

Composting Effectiveness of A Sundry System with A Bin-type Composter for Recyle of Animal Wastes (축분뇨처리를 위한 Bin형 부숙조- Sundry 시스템의 퇴비화효율 평가)

  • 최홍림;김현태;정영윤
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.35 no.2
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    • pp.92-103
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    • 1993
  • A sunday system with a horizontal bin-type composter was constructed and operated to evaluate its composting performance for four days for each test in October, 1992. A sundry system is one of popular systems for composting livestock manure, of which main benefit is to utilize unlimited, clean, and free solar radiation. A rectangular concrete bin(composter) with dimension of 300cm(length) X90cm(width) X60cm(height) was bedded alternatively with four lanes of aeration pipes and heating pipes, and was insulated at three walls with 50mm styrofoam. Each aeration pipe of a diameter of 25mm had 4mm perforated holes at every 15cm longitudinally, and supplied air of about 2m$^3$/min to the composter to maintain aerobic condition . A stirrer rotating at 1 rpm made one round trip every 20 minutes on the conveying chain along the the length of the composter. Five tests (Test 1~Test 5) were implemented to evaluate the composting effectiveness of a sundry system with a horizontal bin-type composter. Treatments of two levels of the mixture ratio of swine manure and paper sludge cakes(manure : paper sludge cakes= 1 : 4 and 1 : 2) and two levels of the water content(W/C ; 70% and 50%) were made to test the significance of the physicochemical properties for decomposition of the mixture materials. Temperature, C/N ratio, water content, microbial activity of the composting materials were taken measurements to evaluate its performance with the lapse of composting time for tests. A small-scale sundry system with a bin-type composter did not appear to be an appropriate system for composting livestock manure. Since heat generation by the composting materials could not overcome heat loss due to areation in a small-scale composter, a proper thermal enviroment could not be maintained to propagate massively thermopilic microorganism relatively in a short period of time. Different from the result of Chol et al.(1992) 6), a temperature variation of the composting materials did not show the peak clearly and C/N ratio didn't lower with time as expected. Mesophilic microoragnism seemed to play an important role for decomposition of the mixture materials. A sundry system with a bin-type composter may be good for a large-scale livestock farm household which may produce enough animal manure. Therefore a decision should be made very carefully to choose a system for composting livestock waste.

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A Fundamental Approach for Developing Deformation Strength Based on Rutting Characteristics of Asphalt Concrete (소성변형과의 상관성에 근거한 아스팔트 콘크리트의 변형강도 개발을 위한 기초연구)

  • Kim, Kwang-Woo;Lee, Moon-Sup;Kim, Jun-Eun;Choi, Sun-Ju
    • International Journal of Highway Engineering
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    • v.4 no.4 s.14
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    • pp.23-39
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    • 2002
  • This study dealt with developing a new approach for finding properties which might represent rut resistance characteristics of asphalt mixture under static loading. Two aggregates, a normal asphalt (pen 60-80) and 5 polymer-modified asphalts were used in preparation of 12 dense-graded mixtures. Marshall mix design was used in determination of OAC and each mixture at the OAC was prepared for a newly-developed Kim test on Marshall specimen (S=10cm) and gyratory specimen (S=15cm), and for wheel tracking test. Kim test used Marshall loading frame and specimens were conditioned for 30min at $60^{\circ}C$ before loading through Kim tester an apparatus consisting of a loading column and a specimen and column holder Diameter (D) of column was 3cm and 4cm with each column having different radius (r) of round cut at the bottom. The static load was applied at 50mm/min in axial direction of the specimen, not in diametral direction. The maximum load ($P_{max}$) and vertical deformation (y) at $P_{max}$ point were obtained from the test. A strength value was calculated based on the $P_{max}$ r, D and y by using the equation $K_D = 4P_{max}/{\pi}(D-2(r-\sqrt{2ry-y^2}))^2$ and is defined as the deformation strength ($kgf/cm^2$). The values of $P_{max}$/y and $K_I=K_D/y$ were also calculated. In general the leading column diameter and radius of round cut were significant factors affecting $K_D$ and $P_{max}$ values while specimen diameter was not. The statistical analyses showed the $K_D$ had the best correlation with rut depth and dynamic stability. The next best correlation was found from $P_{max}$ which was followed by $P_{max}$/y and $K_I$ in order.

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Estimation of the Original Location of Haechi (Haetae) Statues in Front of Gwanghwamun Gate Using Archival Photos from Early 1900s and Newly Taken Photos by Image Analysis (1900년대 초반의 기록사진과 디지털 카메라 사진분석을 활용한 광화문 앞 해치상의 원위치 추정)

  • Oh, Hyundok;Nam, Ho Hyun;Yoo, Yeongsik;Kim, Jung Gon;Kang, Kitaek;Yoo, Woo Sik
    • Journal of Conservation Science
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    • v.37 no.5
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    • pp.491-504
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    • 2021
  • Gwanghwamun Gate of Gyeongbokgung Palace was dismantled and relocated during the Japanese colonial period, destroyed during the Korean War, reconstructed with reinforced concrete in 1968, and finally erected at its present location in 2010. A pair of Haechi statues located in front of Gwanghwamun was dismantled and relocated several times, and the statues have yet to be returned precisely to their original positions. This study assesses the historical accuracy of their current placement under the Gwanghwamun Square Restructuring Project of the Seoul Metropolitan Government and the Cultural Heritage Administration based on archival photos from the early 1900s, and proposes a method to estimate the original positions of the Haechi through image analysis of contemporary photographs and recent digital camera photos. We estimated the original position of the Haechi before the Japanese colonial period by identifying the shooting location of the archival photo and reproducing contemporary photographs by calculating the angle and distance to the Haechi from the shooting location. The leftmost and rightmost Haechi were originally located about 9.6 m to the east and 7.4 m to the north and about 1.9 m to the west and 8.0 m to the north, respectively, of their current location indicators. As the first attempt to determine the original location of a building and its accessories using archival photos, this study launches a new scientific methodology for the restoration of cultural properties.

A Comparative Study on Joy in Russian and Korean (기쁨의 의미연구 - 러시아어와 한국어의 비교를 중심으로 -)

  • Kim, Jung-Il
    • Cross-Cultural Studies
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    • v.41
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    • pp.113-140
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    • 2015
  • This paper explains how the basic and instinctive emotion "joy" is verbally expressed in Russian and Korean. In particular, the main concern of this pater is on the cultural context with which the emotion "joy" is related and the ways in which the emotion "joy" has a wide range of uses. The semantic and pragmatic characteristics of the uses of the expression "joy" can be explained through the cultural and historical backgrounds in both languages. In Russian, joy has two variants, radost' and udovol'stvie. It is very difficult to distinguish a significant difference between them; however, the former is mainly connected with more mental, spiritual, cultural, and religious contexts, whereas the latter is mainly related with more concrete, instantaneous contexts and daily life. The former produces an impression that has a more wide, spiritual, and macroscopic attitude toward a situation, whereas the latter produces an impression that has a microscopic and instantaneous attitude toward a situation. Compared with the Russian expressions, the Korean equivalents, 기쁨 and 즐거움, have a very similar opposition like that of the Russian. The former is based on a more logical and causal relation between an anticipation or desire and the current situations, whereas the latter is based on the participation of speakers in a situation and has a very instantaneous characteristic, like a udovol'stvie in Russian. Thus, it can be reasonable argued that the Russian udovol'stvie and the Korean 즐거움 share many similar semantic properties. In brief summary, in both languages there exists two distinctive variants that show a privative opposition to express the emotional concept of joy.

Environmental Characteristics and Floristic Study of Endangered Pedicularis hallaisanensis Habitats (멸종위기야생식물II급 한라송이풀 자생지의 환경특성 및 식물상)

  • Kim, Lim-Kyu;Choi, Sung-Dae;Choo, Gab-Chul;Hwang, Bu-Yeong;Gang, Geun-Hye;So, Soon-ku;Park, Eun-Hee
    • Journal of agriculture & life science
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    • v.52 no.6
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    • pp.163-173
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    • 2018
  • This study was carried out to propose the baseline data for in situ conservation by analyzing environmental and growth characteristics in Pedicularis hallaisanenesis habitats. P. hallaisanensis habitats, according to investigations, were located on the slope of southwest at an elevation of 1,400 m in Mt. Gayasan and on the slope of southeast at an elevation of 1,500 m in Mt. Hallasan. Pedicularishallaisanensis habitats. Also, habitats were found at the grassland with no upper vegetation. In the study sites, soil pH and soil organic matter were 4.9-6.5 and 4.4-8.1%, respectively. A total of 55 vascular plants taxa were identified in ten quadrats in two habitats, of which 25 were inhabited in Mt. Gayasan and 37 in Mt. Hallasan. Current status of P. hallaisanensis habitats were very vulnerable with the pressure of the vegetation constantly threatening the species' survival. Thus, concrete conservation plans including diverse factors as light intensity, temperature and genetic analysis to protect natural habitats should be set up as soon as possible.

An Analytical Model Proposal Considering Different Surface Type of Bond Behavior between GFRP Rebar and Concrete (GFRP 보강근의 외피형상을 고려한 부착 해석모델 제안)

  • Park, Ji-Sun;Song, Tae-Hyeob;Lee, Jung-Yoon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.23 no.3
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    • pp.150-159
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    • 2019
  • The bond analysis model equation was proposed through the regression analysis of the experimental values of bond behavior for each rebar. In order to verify the appropriateness of the bond analysis model equation, the bond behaviors calculated by the proposed bond analysis model, BPE model and CMR model were compared with experimental values. The proposed bond model showed the closest behavior to the experimental values when compared to other analysis models. The former models can not consider the different properties of GFRP rebar according to composed materials, mixing and manufacturing method and the latter has limitation to express the relationships between bond behavior because of derived formula by numerical analysis. This study proposed the analytical model different considering bond mechanism according to surface type. In order to verity the appropriateness of the bond analytical model, the bond behaviors calculated by the proposed bond analytical model, BPE model and CMR model were compared with experimental values. The proposed bond model showed the closest behavior to the experimental values when compared to other analysis models.

Fishes distribution and their connection to artificial reefs off Bukchon, Jeju Island using geographic information system (지리정보시스템을 활용한 제주도 북촌의 인공어초해역에서 어류 분포와 어초와의 관계)

  • KANG, Myounghee;FAJARYANTI, Rina;JUNG, Bongkyu;YOON, Eun-A;MIN, Eunbi;LEE, Kyounghoon;OH, Woo-Seok;PARK, Geunchang;SHIN, Young-Jae;CHOI, Yong-Suk;YI, Byung-Ho;HWANG, Doojin
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.55 no.2
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    • pp.121-128
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    • 2019
  • Various artificial reefs provide the fish habitat and nursery, and contribute the improvement of fisheries productivity. The evaluation methods of fishery resources in the artificial reefs have been done by fishing, scuba diving, underwater camera, and scientific echo sounder/sonar. There are a number of studies using echosounders on the quantitative and qualitative evaluations of artificial reefs in various seas around the world. This study focused on the spatial distribution of fishes around artificial reefs and the influential area of reefs off Bukchon, Jeju Island. Not only acoustic data but also various properties of artificial reefs were used in the geographic information system to extract relevant results. As a result, the major material of reefs on this study site was concrete and the number of reefs with that material was the most. The volume of reefs consisted of steel only and steel with riprap was considerably large compared to other reefs. The average NASC in the vertical distribution of fishes in artificial reefs was $31.6m^2/nm^2$ in April, and that was $61.3m^2/nm^2$ in June. The distance between the fish school and their nearest reef in June morning had a wide range from 750 to 3250 m. On the basis of the influence ray of artificial reefs, it had a tendancy of NASC to decrease with distance from the reef in the June morning. It is a preliminary study to present the geospatial analysis example to understand a better way of comprehensive artificial reef environments.

Study on Optimum Mixture of Industrial By-Products for Lightweight Foamed Filler Production by Mixture Experimental Design (혼합물 실험계획법에 의한 경량기포 충전재 제조를 위한 산업부산물의 최적 배합 검토)

  • Woo, Yang-Yi;Park, Keun-Bae
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.7 no.1
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    • pp.37-43
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    • 2019
  • This research studied production of lightweight filling production for sink hole restoration utilizing various industrial by-products(2kinds of fly ash, petro-cokes CFBC ash, blast furnace slag fine particle). For this purpose, the mixed raw material properties(compressive strength) behaviors according to the blending ratio of industrial by-products were examined by applying the experimental design method and statistical analysis was performed using the commercial program MINITAB. Compressive strengths of industrial by-products were strongly dependent on blast furnace slag powder. Compressive strength(3days aging) was 3~11MPa depending on the amount of blast furnace slag powder used. The use of CFBC fly ash was evaluated to have the least effect on compressive strength. In addition, the compressive strength and the coefficient of permeability were measured by preparing foamed concrete for the experimental batch 1 condition in the mixture experimental design. In this case, the bulk density is 0.9 to 1.0, the apparent porosity is 30 to 50%, the compressive strength(3days old) is 1 to 2MPa, and the permeability coefficient is $10^{-2}$ to $10^{-3}cm/sec$.