• 한국건축시공학회지
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• 제17권5호
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• pp.393-401
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• 2017

본 논문에서는 발포폴리스티렌 비드 (EPB)와 폐 발포폴리스티렌 (WEP)의 대체율에 따른 경량 모르타르의 기초 특성을 평가였다. EPB 및 WEP를 이용한 경량 모르타르의 기초 특성으로서 단위용적중량, 압축 강도, 휨강도, 흡수율, 열전도율 및 폴리스티렌 (EPB 및 WEP) 분포를 분석하였다. 그 결과 경량 모르타르는 WEP의 대체율이 증가할수록 단위용적중량, 압축 강도, 휨강도, 흡수율 및 열전도율은 증가하고, 폴리스틸렌 면적 분포는 감소하였다.

• 한국멀티미디어학회논문지
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• 제5권1호
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• pp.47-56
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• 2002

멀티미디어 저장 시스템을 위한 기존의 버퍼 캐시 기법들은 멀티미디어 파일의 순차적 접근만을 고려하고 반복 참조는 고려하지 않고 있다. 그러나, 외국어 영상 학습의 경우 사용자가 어떤 장면을 반복 구간으로 설정하면 자동으로 수회 반복 상영하는 기능이 있을 수 있다. 본 논문에서는 순차 참조와 반복 참조가 혼재하는 멀티미디어 저장 시스템을 위한 새로운 버퍼 교체 기법인 HBM(Hybrid Buffer Management)을 제안한다. 제안한 기법은 응용 수준에서 파일의 참조 유형을 파일 시스템에게 알려주고 HBM이 각 파일에 적절한 버퍼교체 정책을 적용한다. 실험 결과, HBM은 DISTANCE나 LRU와 같은 이전 버퍼 교체 기법보다 캐시 적중률을 높일 수 있음을 알 수 있었다.

• Advances in concrete construction
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• 제14권5호
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• pp.341-354
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• 2022

Treatment of solid waste building materials is a crucial method of disposal and an area of ongoing research. New standards for the treatment of solid waste building materials are necessary due to multisource features, huge quantities, and complicated compositions of solid waste. In this research, sustainable nanomaterial mixtures containing nano-paper waste (NPW) and nano-metakaolin (NMK) were used as a substitute for Portland cement. Portland cement was replaced with different ratios of NPW and NMK (0%, 4%, 8%, and 12% by weight of cement) while the cement-to-water ratio remained constant at 0.4 in all mortar mixtures. The fresh properties had a positive effect on them, and with the increase in the percentage of replacement, the fresh properties decreased. The results of compressive strength at 7 and 28 days and flexural strength at 28 days show that the nanomaterials improved the strength, but the results of NMK were better than those of NPW. The best replacement rate was 8%, followed by 4%, and finally 12% for both materials. The combination of NMK and NPW as a replacement (12% NMK + 12% NPW) showed less shrinkage than the others because of the high pozzolanic reactivity of the nanomaterials. The combination of NMK and NPW improved the microstructure by increasing the hydration volume and lowering the water in the cement matrix, as clearly observed in the C-S-H decomposition.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.569-576
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• 2000

This study performs a series of Triaxial Compression Test for clay-sand composite specimens changing area replacement ratio. Purpose of the test is to conform the propriety of weighted average method in estimating shear strength of the composite ground. The test results show that measured values of shear strength of composite specimens are larger by 20∼30% than those from estimation using the current weighted average method. It is thought that the differences are from pseudo-overconsolidation behavior of composite specimens.

• 한국지반신소재학회논문집
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• 제17권3호
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• pp.19-32
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• 2018

GCP(Gravel Compaction Pile, 이하 GCP)공법은 현재 정량적인 설계법이 제시되어 있지 않아 경험적인 방법에 의해 설계 및 시공되고 있어 팽창파괴, 전단파괴 등 다양한 형태의 파괴가 빈번히 발생하고 있으나 명확한 원인 규명과 파괴 예방 대책수립이 어려운 실정이다. 또한 국내와 시공 장비, 재료 특성 등이 다름에도 불구하고 해외의 지반에 적용하는 공법을 그대로 국내에 적용하고 있어 지지력, 침하량 등이 실측값과 큰 차이를 나타내고 있다. 본 연구에서는 GCP공법의 합리적이고 안전한 설계법을 제안하기 위한 연구로써 국내 점토지반에 GCP공법을 적용하여 지반강도 변화에 따른 침하 및 응력 거동특성을 분석하고자 하였다. 이를 위해 ABAQUS를 이용하여 복합지반의 침하량과 침하감소율, 응력분담비, GCP의 최대 수평변위량 및 발생 예상위치를 분석하고자 하였다. 분석 결과, 치환율 30%이상에서 복합지반의 침하감소율이 60%이상 감소하는 것을 확인하였고, GCP의 최대 수평변위량은 말뚝 직경의 2.6배의 깊이에서 발생하였으며, 치환율 40%이상에서는 수평변위량의 차이가 미미한 것을 확인하였다.

• 상하수도학회지
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• 제37권6호
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• pp.409-423
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• 2023

In this study, we analyzed how the revenue water ratio(RWR) is affected by changes in conditions of the water supply area, such as the ratio of aging pipes, maintenance conditions, and revenue water. As a result of analyzing the impact of pipe aging and maintenance conditions on the RWR, it was confirmed that the RWR could be decreased if the pipe replacement project to improve the aging pipe ratio was not carried out and proper maintenance costs were not secured. It was also confirmed that an increase in the revenue water could be operated to facilitate the achievement of the project's target RWR. In contrast, a decrease in the revenue water due to a population reduction could affect the failure of the target RWR. In addition to analyzing the causes of variation in the RWR, the calculation of estimated project costs was considered by using leakage reduction instead of RWR from recent RWR improvement project cost data. From this analysis, it was reviewed whether the project costs planned to achieve the target RWR of the RWR improvement project in A city were appropriate. In conclusion, the RWR could be affected by variations in the ratio of aging pipes, maintenance conditions, and revenue water, and it was reasonable to consider not only the construction input but also the input related to RWR improvement, such as leakage reduction, when calculating the project cost.

• 산업기술연구
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• 제22권B호
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• pp.211-218
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• 2002

The paper is to show the behavior of composit ground which is installed with sheet pile in soft soil improved by sand compaction pile. The results of load-settlement relationship, earth pressure, stress concentration characteristics, and final water content were obtained by centrifuge model test. Two cases of tests, installation of sheet pile on the corner and both side of the loading plate for the improved SCP ground which was designed twice of the footing width, were performed for the tests under the vertical and horizontal loading and both side of corner. Finite element program(CRISP) for sand compaction pile using elasto-plastic model and numerical analysis for soft soil using modified cam-clay constitutive equation were compared and analized with the results of model tests. The result of analysis show the increased bearing capacity of soil after, SCP and sheet pile was installed.

• 상하수도학회지
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• 제31권3호
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• pp.237-248
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• 2017

The estimation method of economical leakage management target utilized upon planning business for improvement of revenue water ratio in South Korea is presented and applicability of methods developed in this study is assessed through application on site. With a consideration of revenue water ratio in application target area, estimation method of long-term economical leakage management target is applied. Three leakage reduction methods such as replacement of residual aged pipe, leakage investigation and restoration and water pressure management are applied with a consideration of characteristics of site. Due to difficulty of obtaining data, analysis of cost/benefit by leakage reduction methods is performed by applying method of leakages estimation equation among statistical methods. As a result of application, revenue water ratio corresponding to long-term economical leakage management target is 91.6 %.

• Earthquakes and Structures
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• 제12권2호
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• pp.201-211
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• 2017

This paper experimentally investigates the effect of yield strength of reinforcing bars and stirrups on the seismic performance of reinforced concrete (RC) circular piers. Reversed cyclic loading tests of nine-large scale specimens with longitudinal and transverse reinforcement of different yield strengths (varying between HRB335, HRB500E and HRB600 rebars) were conducted. The test parameters include the yield strength and amount of longitudinal and transverse reinforcement. The results indicate that the adoption of high-strength steel (HSS) reinforcement HRB500E and HRB600 (to replace HRB335) as longitudinal bars without reducing the steel area (i.e., equal volume replacement) is found to increase the moment resistance (as expected) and the total deformation capacity while reducing the residual displacement, ductility and energy dissipation capacity to some extent. Higher strength stirrups enhance the ductility and energy dissipation capacity of RC bridge piers. While the product of steel yield strength and reinforcement ratio ($f_y{\rho}_s$) is kept constant (i.e., equal strength replacement), the piers with higher yield strength longitudinal bars are found to achieve as good seismic performance as when lower strength bars are used. When higher yield strength transverse reinforcement is to be used to maintain equal strength, reducing bar diameter is found to be a better approach than increasing the tie spacing.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.189-190
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• 2021

Recently, the spread of intense social distancing and untact culture due to COVID-19 has increased the time spent indoors. In addition, according to the International Cancer Institute, fine dust was classified as a first-class carcinogen, a substance found to be carcinogenic, such as asbestos and benzene. As a result, interest in indoor air quality is increasing, and many studies are underway to reduce air pollutants. This study is a basic experiment of a board made to improve indoor air quality. The basic characteristics of the board, flexural strength and compressive strength, are analyzed and the results of the test are as follows. Experiments have shown that flexural strength and compressive strength tend to decrease as the replacement rate of hydrocarbons increases. It is believed that the strength of the sludge has decreased due to the increase in internal voids due to the increase in non-surface area, volume and diameter of microfiber as it undergoes the carbonation process. In addition, it is believed that the amount of moisture needed for curing during the mixing process was reduced due to the absorption of hydrocarbons.