• Journal of the Korean Geotechnical Society
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• v.23 no.7
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• pp.65-76
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• 2007

Recently, there have been many construction projects on soft ground with growth of industry and various construction problems concerning soft soil behavior also have been reported. Especially, foundation piles of abutments and (or) buildings which were constructed on the soft ground have been suffering from a lot of stability problems of inordinary displacement due to lateral flow of soft ground. Although many researches for this phenomena have been carried out, it is still difficult to assess the mechanism of lateral flow on soft ground quantitatively. And reliable design method for judgement of lateral flow occurrence is not established yet. In this study, PNN (probabilistic neural network) and CNN (committee neural network) theories were applied for judgment of lateral flow occurrence based on eat data compiled from Korea and Japan. Predictions of PNN and CNN models for new data which were not used during model development are compared with those predicted by conventional empirical methods. It was found that the developed PNN and CNN models can predict more precise and reliable judgment of lateral flow occurrence than conventional empirical methods.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.2
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• pp.112-119
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• 2023

In this study, the variations in CO₂ uptake according to the type and amount of alkali-based activator (Ca(OH)₂, CSA) of geopolymer paste were evaluated. As the amount of activator added to the geopolymer paste increased, the fluidity of the paste is decreased and the compressive strength increased. According to the type of activator, it was confirmed that the addition of Ca(OH)₂ had a greater effect on improving the compressive strength than CSA. As a result of changes in chemical properties according to carbonation curing, the amount of C-S-H and C-A-S-H gels produced before carbonation increased as the amount of activator increased, and amount of CaCO₃ produced after carbonation increased. The reactivity of the blast furnace slag and zeolite increased due to the addition of the activator, and the reactivity tended to increase as the amount of addition increased. As a result of CO₂ uptake, 10.3 wt% when Ca(OH)₂ 10 % was added and 8.77 wt% when CSA 10 % was added was confirmed. It increased by 421 % and 388 % respectively, compared to the case where no activator was added.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.3
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• pp.161-168
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• 2023

Converter slag is a by-product generated by refining the pig iron produced into molten steel in the blast furnace, occupying about 15 % of the weight of steel production. It has a high free-CaO content that can generate expansion cracks when used for concrete aggregate. This is the main reason to make it difficult to recycle. To solve this problem, government guideline requires that converter slag has to be aged in an open yard for 90 days. However, aging can not be perfectly performed because it entails time and cost. In this study, we tried to investigate the applicability of converter slag as a cementitious material rather than an aggregate by mixing converter slag with mortar formulations. According to the EDS results of the converter slag in the experiment, we found that screening in the aggregate phase was more effective than that in the powder phase. When the particles separated by a magnet in the aggregate state were pulverized and used for concrete up to a 15 % replacement ratio, various engineering characteristics, such as flow, length change, and compressive strength, showed engineering characteristics similar to those of the control mix.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.3
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• pp.184-191
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• 2023

With increasing corrosion in RC (Reinforced Concrete) structures, cracks occurred due to corrosion products and bearing load resistance decreased. In this study, corrosion was induced through an accelerated corrosion test (ICM: Impressed Current Method) with 140 hours of duration, and changes in USV (Ultra-Sonic Velocity), flexural failure load, and corrosion weight were evaluated before and after corrosion test. Three levels of cover depth (20 mm, 30 mm, and 40 mm) were considered, and the initial cracking period increased and the rust around steel decreased with increasing cover depth. In addition, the USV linearly decreased with decreasing cover depth and increasing amount of corrosion. In the flexural loading test, the bending capacity decreased by more than 10% due to corrosion, but a clear correlation could not be obtained since the corrosion ratio was small, so that the effect of slip was greater than that of reduced cross-sectional area of steel due to corrosion. As cover depth increased, the produced corrosion amount and USV changed with a clear linear relationship, and the cracking period due to corrosion could be estimated by the gradient of the measured corrosion current.

• Journal of the Korean Recycled Construction Resources Institute
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• v.12 no.3
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• pp.298-305
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• 2024

This paper is a basic study to improve floor impact noise of reinforced concrete slabs. Considering the case where thickness differences occur due to construction, changes in sound insulation characteristics were analyzed when the cross section of a reinforced concrete slab was restored with mortar. The houses subject to analysis were divided into two types, 84 type and 59 type, with different floor plans. When pre-mortaring was done with heavy mortar to restore the cross section on the reinforced concrete slab, the case was when pre-mortaring was done with the reinforced concrete slab alone and with general mortar. Compared with, the difference between vibration acceleration level and sound pressure was measured. As a result of measuring the vibration acceleration level of the slab after pouring the mortar, the CS mortar was 66.4 dB and the ES mortar was 66.1 dB at 84 type 63 Hz, which was more than 2 dB lower than that of regular mortar. In addition, compared to the reinforced concrete slab alone, CS mortar was reduced by 5.5 dB and ES mortar was reduced by 4.6 dB, showing relatively excellent values. As for the floor impact sound pressure, the 84B type was similar at 63 Hz for CS mortar and general mortar at 67.3 dB, and the reduction compared to the reinforced concrete slab alone was 3.6 dB for CS mortar, 2.7 dB for ES mortar, and 2.7 dB for general mortar was reduced by 1.4 dB. By pouring mortar to compensate for the thickness of the reinforced concrete slab, the vibration acceleration level and floor impact noise were reduced, and when a heavy mortar using copper smelting slag fine aggregate was used, relatively excellent performance was found.

• Cartoon and Animation Studies
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• s.41
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• pp.553-578
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• 2015

The Korean society was forcefully merged with the invasion of Japan in 20th century, and traditional culture of Korea was damaged severely by colonization from Japan. After liberation, Korean society experienced drastic social change with Korean War, and industrial economy and democratic system developed as modernization and democratization occurred. However, Korean traditional culture dissolved more severely as Korean society developed industrial economy and democracy. As criticism of existing Western center of society and the emphasis of cultural identity of non-western regions and third-world, world society preferred exchange of culture of diverse nations and people with each other in advent of postmodernism thoughts in mid-late 20th century. If the cultural identity of Korea was dissolving meanwhile, it was needed to be recovered again. Despite the research in Korean history, language, art, architecture was performed to recover cultural identity of Korea, it did not go in-depth with Korean mythology, for Korean mythology is considered as superstition or savage. Mythology shows subconscious group psychology of people who live in certain specific region. Studying Korean mythology is one of the ways to rediscover cultural identity of Korea. In order for Korean mythology to be known to many people, its stories should be told by media. There were movies, plays, drama, and novels produced based on existing Korean mythology as introduction, then these mythical stories are appear in subculture contents such as recent comics, animation, webtoon, games, and light novels. Then population of game players and webtoon readers increased as dissemination of PC and smart phones, and increasing market scale of subculture contents increased a population of consumers of comics, animation, and light novel. Consumers of sub-culture contents were interested as many of these contents were created, base on Korean mythology. Therefore, this paper is written as research on Korean mythology and its signification in sub-cultural contents which were produced base on Korean mythology.

• The Journal of Sustainable Design and Educational Environment Research
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• v.20 no.3
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• pp.1-10
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• 2021

Before long the number of Elementary School students per class will be 20 in Korea, but the current Area and Module of Elementary School are planned for 30 students. Therefore, necessary Area and Module for less than 20 students should be prepared. The purpose of this research is to find out necessary Area and Module for less than 20 students in Elementary School Classroom. I researched 60 Classrooms of 10 Elementary Schools before 2 researches of mine, and researched the sizes of every path in the classrooms. With the Plans for 20 students, I found the conclusion as follows: First, the one-way class requires a minimum of 5.4m×8.1m (43.74m²), a maximum of 5.4m×8.7m (48.6m²). Second, the 3-row alignment class requires a minimum of 7.2m×7.2m (51.84m²), a maximum of 7.5m×7.5m (56.25m²). Third, the group study class requires a minimum of 6.0m×8.7m (52.2m²), a maximum of 6.3m×9.3m (58.59m²). Fourth, the group study class requires a minimum of 2.34m², a maximum of 14.85m² more than the one-way class. Fifth, the suitable module which fits both 2-row alignment class and group study class except the 3-row alignment class is 6.0m×8.7m (52.2m²).