• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.3
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• pp.53-60
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• 2011

As Construction & Demolition(C&D) debris increase every year, a system has enforced for recycled aggregate made out of C&D debris, then recycled aggregate usage increased in construction field. But as environmental problem by alkalinity of recycled aggregate occurred, the study for lowering alkalinity of recycled aggregate is needed. In this study we made alkalinity reducing facility and installed in the C&D debris midterm-treat field. Then we certified effect of lowering alkalinity and quality of recycled aggregates before and after carbonation. As a result, the most effective carbonation condition is 30seconds in carbonation time, -50~100 kPa of reaction pressure with change of 3cycles. This condition made pH 9.33~9.8 of recycled aggregate possible. The quality of recycled aggregate after carbonation was better than before carbonation in terms of plasticity index, modified CBR, abrasion loss, sand equivalent, liquid limit, size distribution, density and water absorption.

• Journal of the Korean GEO-environmental Society
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• v.9 no.7
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• pp.25-35
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• 2008

In domestic cases, the standard support pattern of 2-lanes road tunnels is presented because construction experience and high degree various data was abundant. But, it is not desirable to apply standard for 2-Arch tunnels that the precedent and measuring data is insufficient existing support pattern blasting plan and interpretation of separate way concerning specific terrain and rock quality. In this study, behavior according to load distribution ratio and Unsymmetrical Pressure about standard support pattern which is applied in design and construction of 2-arch tunnels was analysed and the examination of blasting vibration has influence on the center wall is conducted as a consequence reasonableness of support whether or not with presumed support pressure and ground reaction curve method. In result appropriateness of standard support pattern, support quantity is proper but considers specific terrain and rock quality condition when design and construction of further step 2-arch tunnel standard support pattern must be decided by considering terrains, soil properties and construction condition of the objective tunnel.

• Journal of the Korean housing association
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• v.22 no.4
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• pp.83-92
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• 2011

Apartment is settled down as a main housing type and massive supply has been conducted since 1990's. The government has focused on the housing supply to improve the housing number and cut its price. On the contrary, the management of the housing has been neglected to get an early deterioration. Since 1995's, various ways have been made to improve and maintain the building function and performance. Among these, the long-term repair plan has played a main role to manage the housing condition and plan the repair schedule for preparing the massive cost of repair such as a roof proof, elevator change. The long-tern repair plan provides the repair time and repair rate according to various construction types. Most of the management agent apply the repair standard into the field area. But the repair time could not reflect the present condition and bring into the wrong maintenance. Therefore, the repair time for the long-term maintenance plan would be revised and reflected from the material and technology development. |n this study, it aimed at improvement for the repair time in various construction types which are provided in the long-term repair plan. For this, the 22 management agents are surveyed directly. This study shows that the repair time of the painting are correspondent to the repair time of the long-term plan irregardless of the painting materials. Most of other areas would correspondently similar to the long-term plan. This study could not include the building location, material and other haracteristics. Therefore, the further study would be needed to reflect the building and materials attributes to get the detailed repair time.

• Journal of Korean Home Economics Education Association
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• v.4 no.1
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• pp.57-75
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• 1992

The purpose of this study was to survey the actual condition of education on the western clothing construction in Home Economics and Housework curriculum of high school. And the finding of this study will the helpful to the persons in authority who take part in the course of compilation of the western clothing contruction. The subjects of this study were 101 high school teachers in Chonbuk province. Their responses to the questionaires were analyzed by frequencies and percentiles. The major findings of the study were as follows. 1. Most high school had only a little educational facilities for learning of clothing construction of, if any, they could only show examples in practice. 2 In case of making clothes, students who sew by hand carried out drafting and cutting on their desks in the classroom. When they have practical training, 56.4% of them cheese only one of one-piece dress trousers, and skirt which are presented in the textbook. The related teachers indicated that content composition of the texbook was not fit for the purpose of the students level, and also pointed out the deficiencies of educational facilities, lack of teacher’s research and training, and lack of school hours of evaluation, practical skill was performed in parallel with paper-test at 73.3%. 3. Pajamas and one-piece dress presented in the textbook were the most suitable for the practice at 64.7%. They hoped that illustrations in textbook are so large and full that clothes made through the practice can be worn. Also they hoped that their opinions and wearable guidance will be reflected in the textbook. They emphasized the need of western clothing construction unit because of acquistion of elementary knowledge. The current amount of content composition was enough or excessive. In addition, they understood the curriculum of high school is rather closely connected with that of middles school. Their recognition of the rate of difficulty is very similar to that of other school teachers. They recognized the goal of learning should be applied to the real home life.

• International Journal of Highway Engineering
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• v.20 no.1
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• pp.1-8
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• 2018

PURPOSES : Case studies of an asphalt-overlay project with a performance-based contract method were conducted on a national highway in Korea to evaluate the effect of the method on asphalt pavement maintenance. This study evaluated the procedure of the performance-based contract method. METHODS : In this study, an asphalt-pavement maintenance project for a national highway was assessed with a performance-based contract to investigate the advantage of the new contract procedures. This is the first trial applying the performance-based contract to a pavement-rehabilitation project in Korea. In the four case studies, the warranty period of the performance-based contract was designed for seven years. The research team monitored the construction site to compare the normal contract method with the performance-based contract method. The case studies' project sites were investigated after the end of the construction. RESULTS : Based on the limited case studies, the performance-based contract method could extend the service life of the asphalt pavement and reduce the pavement-maintenance budget because the quality control was well managed by the contractors. However, a few construction laws would be necessary to apply the performance-based contract method in the future. CONCLUSIONS : Using the performance-based contract, the construction company made great efforts to guarantee the warranty period and to apply the optimal maintenance method, based on the pavement distress condition. The contractor and the agency would need to understand the new performance-based contract system for it to be activated. Therefore, a proper education program for the performance-based contract system would be needed to educate the stakeholders regarding the procedures and their effects on the pavement management and maintenance.

• Journal of the Korean Geotechnical Society
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• v.30 no.8
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• pp.39-47
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• 2014

Frost heaving and thawing settlement cause unexpected stress around buried pipelines, which results in deformation and permanent demage. A large scale laboratory test has been performed to observe deformation, stress, and temperature of a buried pipe during atmospheric temperature changes. From the experimental results, the stress concentrated around the buried pipe is inevitable and deformation is caused by the frost heaving. Even though backfill materials are sandy soils which are normally assumed to be non frost susceptible, it is revealed that frost demage can happen due to drainage condition, the level of ground water table, and water content.

• Korean Journal of Construction Engineering and Management
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• v.6 no.1 s.23
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• pp.169-176
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• 2005

The purpose of this study is to analyze the maintenance condition and cost in the past ten year on the subject of permanent Rental Housing in Seoul and Gyeong-Gi. It also suggests the problems and improvements related to long-term maintenance. The Interviews with thirty experts who have had experience in this area more than ten years and data analysis are adopted as basic methods. The data on the maintenance cost such as a budget in practice by a term and the real cost far the repair are analyzed. The primary findings of this study are as follows : 1) the rate of maintenance cost for 13 years is $4.56\%$ when the prime construction cost is regarded, while the figure is $6.70\%$ when the construction cost is considered 2) it is just of forced the basic lists for repair applied commonly to Rental housing. Hence, individually managers consider the features of housing and determine the detail lists.

• Journal of the Korean Institute of Rural Architecture
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• v.13 no.3
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• pp.125-132
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• 2011

By this time the main tendency of studying traditional residential building was to find out and analyze the regional and spacial peculiarity. But that kind of study has been set limits in terms of including each building into one category and being researched by the viewpoint of an observers rather than a resident. Due to this kind of problem, the outcome of that study didn't obtain good results. This study, which has synthetically not been investigated until now, have put a little more deep interpretation on traditional residential building, by surveying Andong Kwon family's Yuhoedang-Chongga located 299 Musudong Daejon. The purpose of this study is to investigate the characteristic of construction in the architecture of Yuhoedang-Chongga of the Andong Kwon family, and to develop the viewpoint and analytic process of traditional construction. As the first step to study it efficiently, basic architectural investigation on Yuhoedang-Chongga has been carried out with an actual evidence, and the new viewpoint of traditional residential building has been developed by this survey such as collecting, arranging, analyzing and examining this positive proof. For example, from the house-picture book handed down from that family, the condition of then established was compared with the present state of it. And then this article examines the arrangement, floor-plan types, interior, structures and condition of location. The transition-history of this house was searched into, and the development process of this was examined. The related documents was synthetically analyzed, so the characteristics of this construction was grasped.

• Proceedings of the Korean Geotechical Society Conference
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• 1998.04a
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• pp.47-60
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• 1998

It is considered in this paper that the main causes of tunnel collapse during the construction were the insufficiency of data of geotechnical investigations, or their limits due to special ground condition such as its heterogeneity and anisotropy It is thought that safety of ground can be affected by the geological conditions such as presences of discontinuities in good intact rocks, and considered to be necessary that awareness of the conditions of discontinuities in advance is important to apply adequate reinforcement measures. It is also shown that a serious accident had occurred because of the unawareness of the permeable alluvial deposits at the top of the tunnel. And it is shown that the example of application of the results of geotechnical investigation such as face-mapping, pilot boring etc. during tunnel construction, and a serious deformation of tunnel under special geological condition. Therefore, it is strongly recommended to perform an adequate geotechnical investigation to confirm the geotechnical conditons of ground before design, and supplimentary investigation is also needed depending on conditions for safe and econonic construction.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.2
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• pp.146-151
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• 2015

Recycled aggregate by the recycling construction waste has a lot of advantage such as the developing the alternative resource and protecting of environment. However, recycled aggregate is used as the low quality grade, because it is difficult to remove old mortar from aggregate. To use the recycled aggregate as high quality grade, it is important to develop the technology to produce the high quality recycled aggregate. To manufacture the high quality recycled aggregate, old mortar attached on the aggregates should be removed efficiently. Therefore, in this study, we suggested the optimum condition to remove old mortar effectively using sulfuric acid and low speed wet rotary mill for high quality recycled fine aggregate. The results shows that the recycled aggregate satisfy on the standards of KS F 2573 in density, absorption and solid volume, when adequate condition of sulfuric mole ratio and aggregate ratio are make.