Proceedings of the Korean Institute of Building Construction Conference (한국건축시공학회:학술대회논문집)
The Korean Institute of Building Construction
- Semi Annual
Domain
- Construction/Transportation > Construction Engineering/Materials/Management
2014.05a
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Planning earthmoving haul-route must be preceded for appropriate equipment fleet assignment. However, traditional haul-route planning methods have limitations relative to practical usage because multiple variables (e.g., grade/rolling resistance, length, equipment's weight etc.) should be considered at a time. Genetic algorithm(GA) was introduced to improve these traditional methods. However, GA based haul-route planning method still remains in inefficiency relative to computation performance. This study presents a new haul-route searching method that computes an optimal haul-route using GA. The system prototype is developed by using MATLAB(ver. 2008b). The system identifies an optimal haul-route by considering equipment type, soil type, and soil condition.
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The objective of this study is the competitiveness evaluation of oversea construction by country in order to provide preliminary data of government policy in 2013. In result the United States ranked first, followed by China(2nd), Germany(3rd), France(4th), and Spain(5th), while Korea ranked 7th overall. In particular, Korea's competitiveness in the construction infrastructures by country ranking(8th) was lower than the competency evaluation results of construction companies by country, therein ranking 7th.
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At the moment, construction industry has negative images such as faulty construction, 3D industry and corruption/bribe and they are being projected onto normal people and those engaged in the industry through various news media. Not only does this worsen the lack of skilled manpower by affecting high school students who will be responsible for the construction industry in the future but also makes the future of the industry uncertain by promoting the avoidance of industrial jobs. Therefore, this study suggested basic data for improving the images of construction industry by investigating interest and images of workers in the industry that high school students think as promising construction manpower, and extracting the present negative images through evaluation of associated images.
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Energy load of building affected by insulation performance of building's exterior. and insulation system can be classify interior insulation, exterior insulation, sandwich insulation according to install place of insulation. but within interior insulation system, corner wall and the cross outer wall-slab insulation part may occur thermal bridges. And then, within exterior insulation system is more superior insulation performance than interior insulation, but it has difficult to apply, easily broken at high building because of strong wind load. And also difficult to maintenance exterior insulation system. So, in this study, to found requirement performance of cast-in-place sandwich insulation system that is superior insulation performance and easy construction and maintenance. requirement performance of cast-in-place sandwich insulation system is 1) To avoid thermal bridges in the insulation performance, 2) Both sides concrete wall can be composite action in the structural performance. Because of this study, can develops cast-in-place sandwich insulation system and this insulation system contribute to improve insulation performance of apartment-house and high building.
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Domestic CM market has continued to grow, and the CM services in the international market is evaluated as a high value-added area. However, CM services are currently being challenged to perform its genuine CM roles because of the limitations by government's CM policies, market size, business functions, and technology capabilities. In order to identify the issues for revitalization of CM, this study analyzed the history of CM studies through a thorough review of the previous literatures that have been published since the enactment of CM policies in 1996. Based on this literature review, it is expected to suggest strategies that could improve current immature CM systems.
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The modular construction is as yet early stage of market in Korea. So It is have difficulty of market demand forecast of the modular building. Therefore, this study was done analysis for market trends of the modular building using ARIMA(Auto Regressive Integrated Moving Average) model by time series data.
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The curtain wall construction applied on high-rise building facades in Korea became generalized, but specialty of the CMr(Construction Manager) who needs to perform economical project management with specialty in the curtain wall construction is still lacking. Therefore, this study analyzed the structure design standard of the curtain wall, researched economical design alternatives. Based on the research results, if the ratio of dead load against wind load is less than 0.1256, LRFD will be more economical.
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As issued the development of energy resources, EPC work process through the IT technology is essential for efficient business management, and systematic management of data generated in this process is needed. In domestic, the research related to system development for the collection and management of construction data detected in the field has been done continuously, but pipeline business target the long-distance in extreme cold weather, almost no cases have been studied up to now. Therefore, this research is aimed to derive the data item for efficient management in EPC Stage of pipeline business in extreme cold weather. WBS system of EPC work are classified easily at two levels, data items can be divided based on the type of document. In the future I will be expected to be the foundation of the systematic management of data generated in the EPC step-by-step of pipeline business.
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Recently, activation of related construction projects due to the large traditional gas resource development of frozen soil region of Russia are expected. It is necessary to provide a plan that can be utilized and collectively managed the occurrence data in the engineering & construction stage for continued contracts of the pipe construction. Therefore, this research is aimed to provide a management plan of occurrence data for efficient management in engineering & construction stage of pipeline business in frozen soil region. The data of the engineering & construction(related pipe construction projects) can be accumulated each version and multiply managed. Furthermore, I will be expected to be the foundation of the systematic management of the classifying based on metadata and the optimizing operations using big data method.
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An infrastructure has been expand with government-initiated series of supporting business in the country rural village. However, there has still been a shortage of it compared to the city. it needs the infra-improvements that making international competitiveness for agricultural competitiveness securing and improving for housing condition. In particular, Public using facilities in rural village are not function as communal identity but life as enjoy culture for farmer. Therefor it is hot-issue that changed rural economy recently is innovated suitable. This study suggests the customized revitalization strategy for the variation of inside and outside of rural communities, after analyzing and classifying on current status of public using facilities in rural village, in chungcheong area.
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Up to now, most the fenestration industry is consisted of glazing and window frame in Korea. According to the Fenestration Energy Consumption Efficiency Rating System and Energy Saving Design Standards of Buildings, u-value of fenestration is defined as the value of calculation with glazing and frame. For this reason, when applying for a building permit, in most cases, the official approval test report of the set of windows and doors is used. Nevertheless, in windows construction progresses, most construction manager take delivery of the glazing and frame separately. For those reason, windows and doors are constructed regardless of the report of the Fenestration Energy Consumption Efficiency Rating System in most construction fields. From now on, the research of the connection method between reality of policy and reality of construction fields should be carried out.
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Sustainable development has become a growing concern throughout the world. Construction industry also has participated in the efforts to minimize the environmental impacts. In Korea, the government has already established the green construction certification(G-seed) and guidelines for sustainable construction. However, domestic guidelines are focused on the design and construction phase, not on the construction project. In addition, it is difficult to find instructions due to the complex structure based on the work unit. Therefore this study aims to deduct the component structure for sustainable construction guidelines in the planning, design and construction phases by utilizing the Factor Analysis. Following the literature review, a total of 26 criteria were identified. Further, a survey was conducted to capture the perceptions on the importance of the criteria. According to the factor analysis, the criteria can be grouped into 8 factors : Environmental factors management, Management planning, Cost and Design management, Energy management, Material management, Certification and regulation management, General Management and Others.
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Cable net system openness and flexibility is good high and the large deflection caused no damage to the structure itself. However, cable installation, install complex systems and technologies are needed. In this study, for the basic materials of cable net construction management, cable net expert's advice and mock-up test results are summarized.
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The appropriate selection of a construction material is important considering the effect on the total project cost and quality. However, the methodologies of the existing systems and databases to suggest search results have been analyzed to lack reliability. Therefore, this study suggests a material searching methodology that results in quantitative results using similarity.
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When various construction types of architectural construction are proceeded in order, the reinforced concrete construction is the frame construction which takes up the most important proportion among the construction process. Thus, the analysis of the effectiveness and productivity of the reinforced concrete construction is necessarily needed for smooth performance of construction projects. However, the conventional studies are performing the analysis of the productivity of only part(mould and steel) of the reinforced concrete construction and they have limitation in that they do not propose quantitatively the overall productivity of reinforced concrete construction.
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According to increase of foreign laborers in domestic, their safety accident is continuously increasing. The purpose of this paper is to draw improvement priority from factors of unsafe act of foreign laborers in domestic. Assessment on each data was performed by Importance-Performance Analysis(IPA) based on safety accident statistics of KOSHA. The result showed that there was required urgent improvement of five factors. The outcome of this study can be utilized in construction safety training and management.
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In order to reduce fatal accidents, a systematic safety management should be performed at a construction site. A lot of researches on direct causes of fatal accidents and indirect causes which affect the direct causes have been conducted for effective safety management. In the previous studies, these causes are considered separately because of the difficulty of recognition of indirect causes. It is also hard to measure the negative impact of these causes and notice their occurrence the perception of its problem. However, a study on identification of complicated relationship between these two types of causes is necessary since an accident occurs due to the chain reaction that indirect causes trigger the direct causes which lead to the fatal accidents. Therefore, this study proposes a safety management plan that considers indirect and direct causes of fatal accidents cases in the Korean construction industry. Then this paper suggests a plan of safety management by identifying major causes of the accidents.
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Today, the potential safety risk is increased due to a construction industry is high-rised, mechanized, and complexed. Most workers injured in accident caused by lack of safety awareness. Therefore the safety education is focused in construction site, but it can not get workers' interest and has many problems to reduce construction accident. This study will investigate the effects of education used BIM intended for workers in construction site to verify the objective effectiveness in future.
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Few studies on crew productivity has been conducted, although the data is significant for time and cost estimation. Crew productivity data was collected for over 9 months from a nuclear power plant and analysed in order to identify factors driving the productivity. It was revealed that the crew productivity of form work, rebar work and concrete pouring work was 45.64(㎡/crew·day), 2.93(t/crew·day), 110.25(㎡/crew·day) on average respectively. Moreover, 'nightwork', 'No. of workers per crew' and 'total work amount' were identified as drivers.
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Process of Cost Estimation in Feasibility Analysis Considering ratio of Renewable Portfolio StandardRecently the Korean government also has strictly restricted a law such as GBCC(Green Building Certification Criteria)and RPS(Renewable Portfolio Standard) on the construction. Especially the government announced a obligation of renewable energy consumption over 12% for all the public buildings of total area over 1,000㎡ since 2014. Regarding to the policy, this study presented the economics of energy analysis of the public office buildings that supplies 12% renewable energy output in the early stage of construction project. This paper calculated on CO2 emission by the geothermal, solar heat, and solar photovoltaic system and estimated the saving cost. Reduced cost through the energy saving are predicted to influence on the total construction cost. As a result air pollution and energy saving cost are expected that renewable energy system would be saving total initial cost of construction on planning phase.
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Recently, BAI(Board of Audit and Inspection of Korea) has recommended that "Result unit cost" of Korean government apply to national power plant construction project when plant owner corporations estimate budget price for tender. but nuclear industry have difficulties with this suggestion. the purpose of this study is to review the "Result unit cost" and problem with application of NPP construction cost estimating. And proposed the direction of application of "Result unit cost" to NPP construction cost estimating.
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Green Frame is a column-beam system that uses composite precast concrete members. Previous studies have proven this system to be not only structurally safe, constructible, and economically feasible, but also environmentally-friendly. If the computerized program is used to estimate the quantity, the result of it shall be calculated much easily, quickly and exactly than manual estimation, because precast concrete members of Green Frame has standard size and connection method between it. Therefore, this study suggest quantity survey concept for column-beam structure comprised of composite precast concrete members. Hereafter, the quantity survey of Green Frame shall be much quickly and accurate, if the system would be made based on the result of this study.
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Although price of construction equipment affects overall cost of a construction projects, the cycle of updating them presented in the Poom-Saem in Korea is more than six years. Recently there is a demand of using the 'Standard Market Price of Construction Equipment', published by the ministry of Security and Public Administration, for estimating equipment operating and ownership cost. It is urgent to introduce an advanced system for updating the prices which can timely reflect market changes.
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The Work Breakdown Structure (WBS) is a primary tool which provides a framework that defines clear scope of all deliverables throughout the project life cycle. Once the WBS is established in projects, it should allow project team members to measure and manage work performances by the WBS; further, it should provide a reference point when any work scope needs to be redefined. Based on the project information in the Progress and Performance Measurement System (PPMS) of UAE's Barakha Nuclear Power Plant (BNPP) projects, an attempt was made to develop a new WBS which provides hierarchical and systematical decomposition of the total work scope of NPP construction projects while avoiding from the preexistence concept in Korean NPP projects that the WBS is a combination of Physical Breakdown Structure (PBS) and Functional Breakdown Structure (FBS). The unique features of the new WBS are as follows: (1) defined the definition of each level of the WBS, (2) subdivided the WBS into 5 hierarchical levels, and (3) adopted globally used general coding structure. The new WBS provides a basic hierarchical structure for the project scope and can be used as a basic tool for schedule control, performance measurement, project status monitoring, and communication among project participants. In addition, by putting the Work Package (WP) under the WBS, the Earned Value Management System (EVMS) per WP can be utilized for the project.
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The structure of construction management service in the Construction Technology Management Act has changed recently. The new Construction Technology Promotion Act becomes effective to support and promote the development of related construction industries and construction technology for domestic and overseas markets. The purpose of research is to analyze the main contents of Construction Technology Promotion Act and to investigate corporate status, problems, and issues. The research is conducted to improve as reorganization of the CM service system based on the interviews with experts. Accordingly the research is to derive countermeasures of CM enterprises. The research results are presented in the following categories of contract awarding, project management, human resource management, general administration and staff education management as countermeasures of enterprises.
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As school facilities have been expanding quantity better than quality, efficient school facility management has been focused on from 2001 in domestic. Due to obsolescence of school facility, objective management and maintenance cost of school facility is very important. However LCC(Life cycle cost) analyst, owner, engineer, contractor and facility manager have a difficulty to obtain and facilitate the basic analyzed data required to analyze LCC of school facility and establish maintenance plan. Therefore this research presents muti-dimensional analysis method through data warehouse technique for supplying maintenance cost information of school facility that can trace and accumulate the scattered LCCing data in the perspective of life cycle of school facility.
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EVM(Earned Value Management) is a management methodology for integrating scope, schedule and resources, and for objectively measuring project performance and progress. EVMS(Earned Value Management System) has been used for the performance measurement of R&D and construction projects in developed countries such as United States, United Kingdom and Australia. The nuclear power plant (NPP) projects in Korea have not applied EVMS. However, EVMS has come into request for overall schedule and cost risk management and performance measurement in overseas project of the nuclear power plant as a contractor. In this paper, based on the global EVMS guidelines, EVMS per unit processes have been developed for NPP projects. Moreover, using Business Process Management (BPM), it proposes an integrated process model with tasks, roles, and procedures for EVMS for NPP construction projects.
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the reference values are high, because the Korean construction standards quote the foreign construction standars indiscriminately. Therefore ten experts were consulted to draw the items about the machine equipment construction standards for project cost saving in this study.
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Recently freeform buildings which are free from simple shape are implemented depending on improvement of construction method. However, freeform buildings are spent more time and cost to materialize than typical form. Because molds for production of freeform shape cannot be reused. For these reasons, low productivity, delay of construction schedule and budget overflow are occurred. Thus, technology of molds need to be developed for manufacturing of freeform concrete segments. The objective of this study is manufacturing of freeform concrete segments using rod type mold. This technology can implement not only application to various shape but also mass production. Thus, problems of construction period, productivity and cost can be solved. After this study, productivity analysis should be continued through the field application.
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Design and construction of freeform building technologies are being implemented to reduce time and cost due to the development of materials and equipments. However, production of freeform concrete segments takes much more time and manpower than typical due to disposable mold and various shape. Therefore, manufacturing technology of freeform concrete segments need to be developed for securing economic and constructive feasibility. The objective of this study is development of efficient casting technology for freeform concrete segments in a short time. This technology includes details about the fluidity of concrete and the sectional shape of freeform concrete segments. And problem of cost and time can be solved. Also, mold can be reusable and freeform concrete segments will be produced quickly and accurately. After this study, productivity study for validation will continue through prototype development and example application.
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Production of freeform concrete segments use various molds because of the unique shape of it unlike common concrete segments. As a result, the mold for freeform concrete segments cannot be reused. Therefor, cost overrun is occurred by needs of more time and manpower to produce the freeform concrete segments compared with common concrete segments. To prevent the cost overrun, a new production method for the freeform concrete segments is needed to develop and the requirements for it should be analyzed before. Therefor, the aim of this study is requirements analysis for production of freeform concrete segment. The requirements of production of freeform concrete segments and form for it is analyzed in this study. The result of this study would be used to suggest the new production method of freeform concrete segments.
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The structural work is the main process of building construction which influence on the time, cost, safety and quality. The form work is one of the main process which has from 20 to 30 percentage of structural work. Especially the form work for beams is complex and need more manpower compared with form work for column or slab. When the existing forms such as plywood form, steel framed wooden form and aluminum form, is used for form work of beam, it would result in the cost overrun caused by needs of lots of manpower and resources. Therefore, the aim of this study is analysis of the requirement for development of SMART beam form. The result of this study shall be used for the development of SMART form work system.
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Recently the concurrent construction method of framework and windows work has been applied for early beginning of exterior finishing works in tall building construction. However, the conventional method makes difficulties in auto-climbing of gang-form and climbing work of lift car since the removal of ACS(auto climbing system) should be preceded for operation of lift car up to the top floor. This study propose a concept model of integrated ACS and lift car system to resolve these problems and begin windows works early in tall building construction.
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In remodeling business or construction of both new strucures and existing structures, Case that pile foundation was set is often. Micro pile, holding compressive force and tensile force by spherical friction, is supported by skin friction rather than end bearing capacity. but, This is weak in tension. Active area of micro pile's skin friction is narrow and micro pile don't do unification behavior hence. So bearing capacity was not fully mobilized in existing researching. In this study, in order to compensate for this method, micro pile to install Resisting Fixture is proposed.
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Stone is one of the oldest and most popular materials used on the external wall because of its durability, abundance and aesthetic effect. However, there are two main problems in the existing pin hole construction method. One is uniformity of construction quality, and the other is a repair work of stone panels. Therefore, a new method is needed to overcome these problems. This paper presents a new stone curtain wall system using under cut anchor and secondary holes that was developed by authors. The improved quality and reduction of construction period can be obtained by this system.
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This study is concerned with the VS shear reinforcement that it can be installed easily in filed as product at the factory and seismic performance can be achieved. The method of study is as follows. first, we researched constructability and economy of existing construction method. Secondly, we made specimen and were examined structural performance tests in order to verify the performance of the shear reinforcement for lateral force like seismic load. As a result, developed VS shear reinforcement increased in shear strength and stiffness of reinforcement, structural safety is judged to be increased.
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Generally significant reinforcement is used for nuclear power plant structures and may cause potential problems when concrete is poured. In particular pouring concrete into structural member joint area is more difficult than other areas since the joint area is very congested due to hooked bars, embedded plates, and other reinforcements. The purpose of this study is to solve the problem by applying high-strength(ASTM A615 Gr. 75/80) bars. In addition large-sized(#14 & #18) headed deformed bar could be used as alternative of standard hooked bars to relieve the congestion to some extent. In order to apply headed deformed bars to nuclear power plant structures effectively, the large-sized diameter bars and the high-strength bars shall be used as thick as clear cover thickness 1". Therefore, test results were obtained by taking bar size, yield strength, and clear cover thickness as variables.
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Concrete with self-healing admixture can reduce the crack width by using a compound for chemical reaction with incoming water and carbon dioxide through the crack. Also, concrete with self-healing admixtures can reduce early-age shrinkage crack by using a inorganic expansive agent. In this research, we perform the basic workability test and compressive test. Also, We measure the drying shrinkage of concrete specimen. Finally, we make mock-up (3m X 3m X 0.23m) and monitor the crack width and length for 3 months.
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Green frame is column-beam structure composed of precast concrete members. Based on Revision of Structural Concrete Design Code, the bottom rebar of beam shall be extend at least 150mm into the support member. However, if the bottom rebar extend to satisfy Revision of Structural Concrete Design Code, the installation fo beam is impossible due to interference between the columns and beams. Thus, the aim of this study is estimation of production length of precast concrete beam by using splice length of bottom rebar. In this study to solve this problem, lap splice were used on the join. This study was calculated length of the reinforcement by the diameter. According to the length of the rebar, the production length of beam concrete was calculated. The results of this study will satisfy the Revision of Structural Concrete Design Code about column-beam connection when green frame will be applied.
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Recently, construction project has greatly increased the needs for cost savings due to excessive competition and economic recession. The purpose of this study is to introduce application of building using optimal design technique for improving constructability and economic efficiency of structural wall. As a results, design results of irregular wall show about 15% reduction of the longitudinal bar compared to single walls and ultimately improve constructability.
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In this study, the effect of very fine sand on drying shrinkage cracking of concrete was experimentally evaluated. As a result of the study, the time-to-cracking of concrete used very fine sand was shorter than plain concrete. Also, the stress rate of concrete used very fine sand was higher than plain concrete. It was due to the increase of water content when very fine sand was used in concrete. In conclusion, the use of very fine sand can lead the increase of water content to meet the target slump and higher potential of cracking of concrete.
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This study was carried out to process the shape of dry bottom ash using the impact crusher and gravity crusher, which are identified as most effective in improving grain shape through the preceding research, and a comparison was made between concrete that utilized the processed dry bottom ash as aggregate and concrete containing dry bottom ash before processing to understand properties of the new concrete.
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The purpose of this study is to evaluate the corrosion protective property of Al-Mg high-freqeuncy arc metal spray method in comparison to Zn-Sn and Zn-Al alloys by electrochemical method and CASS test. As a result, it appeared that Al-Mg alloy had very higher corrosion protective property through the electrochemical characteristic and the CASS test comparing with the other alloys.
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The purpose of this study is to analyze the adhesion strength of metal spray coating system in steel using high-frequency arc metal spray method. For the purpose the experimental factor such as surface roughness was selected at 3 levels. As a result of experiment, it appeared that high-frequency arc metal spray method had higher adhesion strength than existing metal spray method. Especially, Al-Mg showed the highest adhesion strength than other metals. In case of surface roughness, the higher roughness steel has, the higher adhesion strength appeared.
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The newly developed eight-directional collector was installed at five different locations in the coastal area after its functionality was verified through experiments. Based on the airborne chloride amount measured for one year, the distribution characteristics of airborne chlorides were examined by direction. In terms of direction, a large amount of airborne chlorides was collected, not only in the direction facing the coast but also in the opposite direction. The amount measured at effective three directions was 1.5 times that measured at non-effective three directions.
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The global warming because of the CO2 emission and solution about this emerge as the international enviroment problem. Particularly, it is the absolutely it is needed for reducing the CO2 in the cement industry and harmful material actual condition. And the construction of home and abroad and material manufacturers tries for the technology development for the carbon dioxide and harmful material reduction which the portland cement in manufacture is usually emitted along with the increase of concerns about the environment-friendly concrete and panel. Therefore, in this research, the compressive strength of the inorganic binder and flexural strength tries to be measured in order to draw the inappropriate high temperature cure time of the ternary system inorganic binder using the blast furnace slag, red mud, silica fumewhich is the industrial byproduct with the cement substitute material, and etc.
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Due to the nature of the existing load, the criteria of assessing the intensity of the lightweight wall's impact resistance has been though of as obscure. The current study, therefore, focuses on the standardized assessment of the impact resistance to the force of the large soft body applying to the lightweight wall. The gypsum board wall showed a low level of the maximum residual displacement. It is, however, required to be careful about the selection of the finishing process since the high level of the maximum displacement is likely to cause harm to finishing materials. Unlike the gypsum board, the ALC block wall displayed a considerable rigidity while showing almost no maximum residual displacement. Even with the low level of the maximum displacement due to the stiffness, the ALC block wall is still likely to be affected by the vibration derived from any impact on the surface, which demands a need for additional study. The future experimental study, accordingly, will focus on the impact of the vibration on finishing materials, consequently leading to the accurate prediction of the possibility of potential damage to the lightweight wall caused by the large soft body.
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In this study, fundamental properties of mortar with the variation of dosage of anti-rust agent has been tested to evaluate the effect of the anti-rust agent. Dosage of anti-rust agent was fixed as 0,3,6,9%, respectively. The variation of the flow, compressive strength and diffusion speed of chloride ion has been tested to evaluate the effect of the anti-rust agent. Results showed that flow has been smally increased. For the compressive strength, compressive strength increased with the increase of dosage of agent. For the diffusion speed of chloride, the speed decreased with the increase of dosage of the anti-rust agent. For the overall consideration, it could be identified that when the dosage of anti-rust agent was fixed as 3-6%, the mortar showed the optimum performances.
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This study dealt with an experimental study on development of tile grout cement complied with international standards criteria. Tile Grout Cement is divided two grade, 1 type and 2 type, in KS F 1592:2011. International Standards(ISO) is divided 9 grade. performance evaluation for cement content was measured according to KS L ISO 13007. water absorption test results are based on the cement content 30% were satisfied with International Standards criteria. strength test results are based on the cement content 25% were satisfied with International Standards criteria.
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The purpose of this study is to enhance durability of solidifying mat. solidifying mat excellent mechanical properties of geotextile. multi-layer coating system is applied to the mat and the chloride ions penetration resistance, chemical resistance, accelerated carbonation test were evaluated by testing the durability. Durability test results are as follows. chloride ions penetration resistance results are coated mat is approximately 70 % lower than plain. chemical resistance test results are coated mat no discoloration. accelerated carbonation test results are coated mat is approximately 90 % lower than the plain.
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Amount of slag which is a recycled aggregate that be produced as a industrial by-product from steel production process is increasing. But there is few suggestions for usage of slag except for shaft furnace slag and studies for utilizing this are lacked. In this study, it reviews flow characteristics according to replacement ratio of rapid cooling steelmaking slag from the perspective of rheology. Replacement ratio of ps ball is used by replacing 40, 45, 50% for each binder mass.
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This study was done to resolve the air reduction in mortar when mixed with ERCO. Effects of the water repellent ALC powder due to its particle size and substitution ratio on the cement mortar with ERCO was analyzed. Results showed more water repellent ALC powder ensured more air but did not affect the size of particles. It was determined the compression was caused by more air and water added to achieve the flow. Therefore, substituting with water repellent ALC powder may compensate for the air reduction in mortar with ERCO. Other measures and approaches are needed in order to resolve the reduced strength.
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Recently, the construction structure repeats the brilliant development including the shper high rising, high functionalization, environmental friendliness, conversion to ubiquitous, and etc. upon with the construction industry development and it is continually soothed. Meanwhile, as to the construction structure of the modern society, the research for corresponding to the box-frame construction way where the response to the diversity of the life of the occupant is difficult is needed. Thus, the lightweight of the structure is the important factor in order to secure the functionality. Therefore, this research tries to study the water absorption ratio and flexural strenght of the magnesium oxide light weight matrix according to the powdery modified sulfur addition ratio.
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This study is to environmental safety assessment of ground solidification materials using industrial by-products. also, physical and chemical properties were investigated. as a result, compared to conventional cement the survival rates are capable, was judged to be possible utilizing of ECO-friendly ground solidification materials.
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A fire in a steel framed building can decrease a structural stability and cause deformation. And the fire continues the building can be demolished. Therefore, every country requires fire resistance performance of structural elements. In case of column, fire protective thickness derived from a specific fire test using an horizontal furnace is allowed to apply any kinds of sections and lengths of column. However, the lengths and sections of the column in steel framed buildings are various. In this paper, to know the differences of fire performance of steel column according to variance of lengths, a maximum allowable stress, steel surface temperature history, deflection are calculated and the thickness of fire protective material for longer column(4700 mm) need to enforce about 10% more than shorter column (3500 mm).
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Measurement of the strength of concrete is an important indicator of the safety of the fresh as well as old concrete structures. It is possible to evaluate the strength of the concrete by means of an ultrasonic velocity method which is a kind of non-destructive inspection method for safety diagnostic evaluation of the building structures with aging. Steel embedded in the concrete and age of the concrete may affect ultrasonic pulse velocity. In order to accurately assess the strength of the concrete, it is necessary to understand rebar embedded in the concrete, steel shapes in various forms which effect ultrasonic pulse velocity. In this study, by measuring the velocity of ultrasonic waves generated when the waves pass through the ultrasonic pulse in a direction perpendicular to the reinforcing bars embedded in concrete, the effect of reinforcing bars on ultrasonic velocity accurately was verified and used to estimate the strength of the concrete.
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Polymer concrete has more excellent durability, tensile strength, flexural strength and waterproof performance mechanically than normal concrete, and as it mixes as a polymer binding material, it can reduce the cement use amount. This study reviews fundamental properties of cement material mixed with complex polymer. As a result of this study, as percentage of complex polymer mix increases, flow value will decrease so that liquidity and compression strength will decrease. On the other hand, in case of flexural strength, when the mixture is 10%, it increases significantly more than OPC.
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At construction sites, due to the reason of inconvenience and difficulties of producing and using curing equipment and when it comes to measuring compression strength of the actual structure, strength of structure concrete according to general standards which are suggested in concrete standard specification are assessed. However, this method does not consider various variables of the sites such as kinds concretes and sizes of frame works so that it is not easy to measure proper curing period and strength. Thus, this study reviews description of strength development according to In-situ temperature system and analyzes and compares properties of strength development of the existing curing methods such as sealing curing so that it provides basic materials for period of removal of molds.
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In this study, flowability of the mortar added with length change and combination of steel and inorganic fiber has been tested to evaluate the performance of fiber-reinforced mortar. The following results could be made as the conclusion. Early age flow of the mortar has been decreased when fibers added. Slump also decreased with the adding of fibers. For the air content, comparing with Plain, all the specimens with fibers showed higher air content than Plain., Addition of every kinds fibers showed the similar EIS test results.
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In this study, Analyse about flowability for fiber-reinforud mortar has been focused. Organic and inorganic fibers with different length have been combinatiorly used. The results showed using combination length of the fibers decrease the flowability, comparing with plain, fracture styess has been increased, Results also showed when several kinds of fibers used together showed the highest fracture stress.
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Huang, Jin-Guang;Park, Jae-Yong;Jung, Sang-Woon;Jeung, Kwang-Bok;Han, Min Cheol;Han, Cheon Goo 132
In this study, high volume of industrial by-products including blast furnace slag, recycled aggregate powder and incineration ash have been utilized on the slurry of the foamed lightweight concrete. As to decrease the price of the lightweight foam concrete, mortar based slurry and concrete based slurry has been fixed. As the variation of the foam conduction ratio and aggregates, the foam ratio and compressive strength has been tested. Results showed that using recycled aggregates in the slurry showed better effect than using natural aggregates due to the alkali properties of the recycled aggregates could activate the potential hydraulic properties of the blast furnace slag. Consider about the low price of the recycled aggregates, it could be identified that using recycled aggregates in high volume blast furnace slag blended lightweight concrete showed better compressive strength than natural aggregates. -
In this study, mock-up test for high strength concrete with ERCO has been carried to analyse the effect of autogenous shrinkage reducing of using ERCO. The following results could be made as the conclusion. Results of EIS were lower than 2.5 and showed good resistance for separation of materials. For the setting time, specimen with ERCO showed delay of setting comparing with Plain. For the autogenous shrinkage, as the generation of saponification, capillary pores inside the concrete were filled by soap and the autogenous shrinkage has been obviously decreased. It could be identified that using ERCO in high strength showed good effect on reducing autogenous shrinkage in high strength concrete.
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In this study, fundamental performances of high strength concrete with ERCO has been analysed according to mock-up test. The following results could be made as the conclusion. For the fresh concrete, flowability and air content decreased with the addition of ERCO, and all the specimens satisfied the target range. For the strength properties, all the specimens with different nominal strength showed higher compressive srength than Plain which with 0% dosage of ERCO.
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In this study, conventional aggregate obtained from a ready mixed concrete factory and the aggregate with a modified grading produced in lab. condition were prepared. Results showed that a good grading of aggregate the ratio of 5~13 mm and 13~25 mm is 20~40 % produced in the lab. condition significantly improved the slump and the compressive strength of the concrete.
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Nowadays, as to increased the workability of the press concrete and decrease the cracking, the fiber-reinforced admixture has been widely used. As the low adhesion force between the paste and fiber-reinforced admixture, it was considered as could not be used in the structure. Even more, as the loss of flowability and the exposure of the fiber, further study is needed. In this study, as the different environment and position of the building, the dosages of the fiber-reinforced admixture has also been changed. The fundamental properties and cracking of fiber-reinforced concrete have been tested.
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In this study, as to enhance the efficiency and workability, binder contained 3 types of gels have been used to replacement the OPC. Fundamental properties and length change of the concrete have been tested to evaluate the effect of different binders. The following results could be made as the conclusion. When the binder contained 3 types of gels used, the flowability increased, whereas the air content decreased. There showed some different air content when the component of binder changed but the difference was consider as limit. For the strength properties, with the using of binder contained 3 types of gels increased the strength. Specimen of FA20SF5 showed the better strength and lower length change of drying shrinkage than other specimens.
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Nowadays, as to increased the workability of the press concrete and decrease the cracking, the fiber-reinforced admixture has been widely used. As the low adhesion force between the paste and fiber-reinforced admixture, it was considered as could not be used in the structure. Even more, as the loss of flowability and the exposure of the fiber, further study is needed. In this study, as the different environment and position of the building, the dosages of the fiber-reinforced admixture has also been changed. The fundamental properties and cracking of fiber-reinforced concrete have been tested.
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In this study, as the resistance of the carbonation for high volume admixture incorporating concrete, coating effect of using refined cooking oil in the surface of high volume admixture incorporating concrete has been tested. The following results could be made as the conclusion. For the fresh concrete, the slump and air content has been identified as satisfying the target range. For the hardened concrete, comparing with specimen of Plain, specimen with coating showed better long age compressive strength. For the carbonation speed, the specimen of FA30 showed highest speed and the specimen of BS60 showed higher speed than specimen of Plain. For all the specimens coated with RCO, as the decrease of capillary pores inside the concrete, the carbonation speed has been obviously decreased and with even better effect than using PEP coating. It could be identified that specimens with coating by RCO showed good effect on refrain the speed of carbonation.
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In modern society, population overcrowding and concentration of facilities are happened because of the concentration on to city. So this phenomenon demands improvement of material's performance, technical development of structure analysis and design and improvement of constructing ability .High strength concrete has some merits. High strengthening makes the cross section reduced, and that cause decrease of structure weight. And using high durable and superplasticizer promote liquidity, thus high quality concrete can be produced. Because of these advantages, this study is for showing validity of using it by compression/tensile strength experiment. As this experiment's result, when concrete become stronger, interface intensity coefficient between cement and aggregate is different and they don't adhere to each other. So there is brittle failure. Fragility factor also steadily increase with strong concrete, it tells high strength concrete has problem. Therefore the sources used in high strength concrete like cement and aggregate must have great quality. So the source's performance must be supervised well because their quality decides performance criteria.
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A mold of free-form concrete segment can be used only one time. Thus, the construction duration and cost are increased. The materials of the mold such as wood and metal have limitations due to the implementation and reuse. The review of the material of the mold for free-form concrete segment is needed to reduce duration and production cost. Phase change material can be used both to implement free-shape by heating and to produce mold after cooling. After using Phase change material can be re-used to mold by heating. The scope of this study is many kind of phase change materials for molding. The aim of this study is to analyze the phase change materials for production of changable mold for free-form concrete segment. In this study, the paraffin wax that is melted at 64℃ was selected by considering both the energy efficiency and the weather of Korea.
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Small photovoltaic equipment spreads to the detached house owing to the support of government. This study analyzed the payback period of small photovoltaic equipment, and presented a plan of spreading PV equipment by electricity consumption according to the results. The results of payback period analysis showed that a household of 500kWh or above in the average monthly electricity consumption could produce an economic effect without the subsidies of government, and a household of 300kWh or above could secure economical efficiency in case of receiving the subsidies of government and municipality. However, it was shown that the economic effect was not large in case of a household of less than 250kWh. Therefore, the analysis showed that it would be necessary to be supported by additional subsidies or to develop a new supporting policy with regard to a household of less than 250kWh.
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PC apartment house 15 years have elapsed have various deteriorations by water leakage in roof and wall. The prior investigation such as investigating of leakage repair history of PC apartment and the field investigation were carried out to solve the water leak problem in its structure. The path of water was analyzed on the parts of greatest water leak such as roof parapet, roof floor, side wall, corridor and balcony. As a result, the specific path of the water leakage was identified in various structure units.
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There is urgent for defect consulting work to standardize the investigated method, repaired and reinforced method, and estimated cost about defect in increasing a defect lawsuit of apartment building. For the purpose of developing the standard process of defect consulting work, the review that a used process in law and institution should take precedence. There is not prepared the national standard for defect consulting but is dependent on an experience and a practice of consultants. This study analyzes defect consulting case, defines main steps for developing the standard process, and draws phased work factors. As systemizing this, it is expected to apply to basic structure for developing the standard process of defect consulting work for the next.
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This paper describes the classification problems of the unit modular housing through reviewing design drawings. Modular construction is a new industrialized homebuilding technology that uses large, factory produced modules. In general, more than 70% of construction processes in unit modular construction method are produced in factory after that the modular, which is completed is lifted on site and assembled. This research considers categorization in which the design drawing of the unit module housing can have problems. There are 17 types of construction method and 14 types of design approach as a result of the classification.
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Operation and maintenance stage consists the largest portion of project life cycle cost. Appropriate management and analysis of such stages have massive effect on the total project cost. The effective prediction of optimized repair period is one of main factors in ㅌ management. However, it has been analyzed that the prediction of appropriate repair period revealed limitations in reliability. Therefore, this study suggests a methodology of repair period prediction by dividing finished projects into similar groups with same properties to be compared with the target project using quantitative variables.
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In the case of U.S, various damage prediction models of buildings from natural disasters have been used widely in many organizations such as insurance companies and governments. In South Korea, although studies regarding damage prediction model of hurricane have been conducted, the scope has been only limited to consider the property of hurricane. However, it is necessary to consider various factors such as socio-economic, physical, geographical, and built environmental factors to predict the damages. Therefore, as a basic study on a damage prediction model development of buildings, this study is to analyze the correlation between various factors related to hurricane. The findings of study can be utilized to develop for predicting the damage of hurricane on buildings.
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Recently, in according to increase cognizance of energy and resources exhaustion, renewable energy system is received attention. In particular, ground heat pump system(GSHP) utilizing annually stable ground temperature for energy saving have been attracted in many buildings. However, GSHP system have disadvantage due to increase of initial installation and boring cost. In this study, in order to reduce the initial cost and to supply ground heat pump system into small scale house, an unit-type ground heat exchanger was developed.
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Construction Technology Service is currently hardly managed due to failure to offer standard management system of service performance, company performance, and business evaluation in every Ordering Agencies. After Construction Technology Promotion Act is enforced in May 2014, Ordering Agency obligates them to report to Minister of Land and Transportation within 10 days upon contract/ amendment/ completion. In 2013, in advance to enforcement of this law, performance management system for construction technology service was developed for a test run. However this system only applies to main contractors while management and operation of subcontractors are unavailable that causes problems on connection and integration with Experience Management Trustee. Therefore, this research will establish systematic foundation that enables real-time information of service performance and evaluation of subcontractors to result standardization of performance and evaluation for public ordered services.
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The buildings constructed with steel structure is coated with certified fire resistive material to resist from fire. Coating materials lose their initial performances as time passes, so they need some maintenance. This study is covers standardization of the methods for assessing the durability of SFRM. In Korea, more than 90 percent of SFRM are used indoors. So This study is to decide proper test method through investigation and examination of effect factor to performance of fire-resistant structure and applicable test method.
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The study is used to verify the applicability of the sensor to monitor penetration of chloride into the concrete, like real coastal environment. After manufacturing the specimen adapt corrosion sensor for chloride penetration monitoring, chloride spray experiment was conducted. And then, It was checked the possibility of monitoring of the penetrated chloride by measuring the resistance of the corrosion sensor that was embedded in each depth of the concrete. Experimental results, it is confirmed that the corrosion resistance of the sensor was increased depending on the concentration of chloride. Therefore, it is estimated that the sensor is available for monitoring of chloride penetration.
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A Rural house in Chungcheong area have been variety of matters, rapid deterioration of house and incomplete of maintenance control, that is represented lack of durability heating from lack of heat insulation property, health worsening form use of toxic substance and so on. For farmers who did not know where to repair and how to repair, they are urgently needed measures of standard and basis that is to realize a condition of rural house. Accordingly, this study drew major matters and priority for revitalization through analysis of type of rural house from research on the actual condition in order to develope of diagnostic criteria of rural house.
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Although the modified epoxy mortar can be applied to the reinforcement for RC member, the mortar has been little used in construction site. In addition, there is a few studies regarding the experiment as the material improving the seismic performance. Therefore, this study is to propose an effective reinforcement alternative for RC Ordinary Moment Resisting Frame (OMRF) through evaluation of seismic performance and economic analysis. The findings of this study can be utilized as the basic data in construction sites when the modified epoxy mortar is applied for seismic performance reinforcement.
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Corrosion is very serious problem in RC structure under ocean environment. There is no enough experiment information using the reinforced geo polymer concrete applied by electo chemical protection system. Three condition, such as tidal zone, submerged zone and crack were simulated to geo polymer specimen. Corrosion rate and natural electrode potential were measured through accelerated test. Anti corrosion property of geo polymer was better than OPC regardless of specimen condition and applied time.
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International construction contracts to Korean construction companies have been dramatically increased over the 48 years (Contract received worth 65.2 billion dollars in 2013). Especially, the plant construction sector has achieved about 61% among the 65.2 billion dollars. Under this trend, in order to ensure plant construction's competitiveness, 'standard classification' is an important area for systematic management. However, these standards in the plant construction are not widely utilized yet, in comparison with civil and building sectors. Therefore, in this research, a higher level of standard classifications is proposed for various types of power plants from a PMO's (Project Management Office) perspective. This study also provides a comparative analysis outlining different features and common components based on various types of power plants.
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The principal government building of Kyungsanbuk-do was designed to show korean traditional architecture with tile-roofed house to reflect the image of Kyungsangbuk-do as the province of traditional culture. The roof of korean traditional architecture is the most importanat part that distinguishes the design character of a building and is important to determine degree of completion. As this is so, in the design phase, we reviewes the design documents about the proportional and slope of the roof, durability and sizes of component material and the structure of eaves. In the construction phase, it was required to cooperated with specialists of traditional architecture for realization of traditional beauty of the buildings as designed.
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Recently, structural system of apartment building is changing from wall type to column type to accommodate various life styles of residents in Korea. Reinforced-concrete bearing wall structures have been mainly used in apartment construction since 1980's. It is impossible to remove the bearing wall in case of remodeling a house, so that the lightweight wall is needed to apply to the column type structure of the Long Life Housing. Therefore, the purpose of this study is to evaluate the construction performance of the wall. Constructibility reviews are performed throughout interview survey from builders who charge with managing the construction of the lightweight wall in field. This paper present that constructor prefer the bearing wall rather than the lightweight wall because of the schedule delay, difficulty of management, and lack of skilled labor. The results indicate what we should improve on the lightweight wall from now on.
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Recent construction sector integration and fusion technologies in various areas of research and planning systemis being maintained by the system. Past experience of conservative management in this emerging technology-driven business management through the convergence of various technologies and to find synergies to secure the future of construction technology because it is a need. The purpose of this study is builton the basis of technical and Technology Management Contact optimized system for integrated management of the area you want to build.
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Due to the decreasing domestic construction market since 2007, Korean construction companies are expanding overseas market. As a result, the international market share by Korea has been continuously increased and achieved 65.2 billion dollars in 2013. Despite of such visible results, profitability concerns are constantly arising. It is pointed out that the low-priced bid competition between Korean construction companies and various unpredictable risks are the most crucial factors which aggravate the profitability in the overseas projects. From this point of view, predicting the risks in advance and controling them could be the most important tasks to improve the profitability. This research proposed 202 risk factors with a hierarchy and relational database schema for power plant construction, which is based on the 24 risk classifications in previous research (Kim & Jung 2013). Proposed risk classification and relational database schema could be utilized as the basic data in risk management system.
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In modern building, it is constructed with non-uniform complex design. These buildings can't be expressed in 2-D drawings, and it requires shown in 3-D. So, BIM is necessary to communicate between a designer and constructor, and it prevents misunderstanding of drawings. Especially, to design and construct these non-uniformed buildings, BIM needs knowledge and know-how of structure engineer. BIM should fully include construction process information which satisfy constructors so it leads to success in construction market. In this Thesis, I show some example of BIM efficiency to construct non-uniformed large scale building.
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Low carbon construction is an important operation management goal such as cost, time, and quality in construction community. This paper introduces a system which measures the variability of carbon dioxide amounts. First, this system allows creating construction operation models of which the level of detail is breakdown into the work task level. Second, the system implements sensitivity analysis along with a ranges of resources that are allocated in an operation model. It facilitates to find the optimal resource combination using the operation performances such as the amount of emissions, operation completion time, and cost. Lastly, it identifies the best fit probability distribution functions of performance criteria given a certain resource combination. It allows project manager to query the percentages to complete the operation within a limitation specified by the system users.
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In construction management the estimation procedure of construction expanses follows a series of submission phases: production of drawings, the assessment report, and the expanse report. In South Korea, it is a widely known issue that the expanse report only includes the net expanses at each construction phase and part, which makes it difficult to trace detailed basis from the records. This issue with inefficient record management should pose a number of problems, which result from discontinuation of construction record, unproductiveness for reproduction of records at each construction and submission phases for construction management, and failure to perform fair management among the contracting parties. Thus, the amendment in which the assessment report and the quantity estimation report reflect common codes to share throughout types of construction, space, and parts should be applied into practices so as to model production of acceptable reports and record.
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The construction industry in recent years, due to the multi-species engineering specialty, interest and importance of human resource management is growing. But, not many studies on the operation ratio are being proceeded due to the difficulty of casting people on site and actual survey. Thus, this study proposes the work type-specific quantitative operation ratio through work type-specific operation ratio analysis of reinforced concrete construction which takes up an important part of construction work.
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Among common test methods of assessing structure safety for existing lightweight walls, the criteria of the quality assessment of the horizontal static load resistance has been considered ambiguous. In the current study, therefore, an experiment was conducted to figure out the standardized assessment criteria of the lightweight wall's horizontal static load resistance. Based on the findings of the experiment with gypsum board and ALC block walls, an acceptable amount of each standard and the variables of the stud wall arising from the appropriate load (1000N) on the wall in a daily life were accounted for, arbitrarily setting the maximum deformation amount below 15mm.
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Blast furnace slag is one kind of industrial by-product and was utilized with recycled fine aggregates for the manufacture of zero cement mortar. As the blast furnace slag was from different areas, the strength of the specimen using blast furnace slag showed different performances. In this study, blast furnace slag generated in different areas in Korea has been chosen, fundamental performances of the blast furnace slag blended mortar has been tested to evaluate the quality of the blast furnace slag. Results showed that difference for flowability is limited. As the alkali activation of the blast furnace slag, the compressive strength showed different results. The flexural strength showed little difference when the aggregates and types of blast furnace slag changed.
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Recently, many environmental problems occur due to the waste shells in South Korea. In case of oyster and cockle, utilizing waste shells to produce fertilizer once also, but due to sluggish consumption, production is no longer difficult. The stored amount of waste shells in the fertilizer manufacturing company is overfilled, and thus cannot accept any more of the waste shells. As a result, landfill and dumping of waste shells have become an increasingly environmental problems. In this research, the basic physical properties and interfacial bonding form of the mortar mixed with waste shells (manila clam, cockle, clam, sea mussel, oyster) were evaluated.
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Nowadays, as to reduce the emission volume of CO2, blast furnace slag has been widely used to replacement of cement. Techniques about using industrial by-products has been extensively studied. For the previous study, blast furnace slag has been used with recycled fine aggregates. In thess study, considering about the different properties of blast furnace slag, as the change of blaine and chemical performances of blast furnace slag, the results of flowability and compressive strength has been analysed.
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In case of fire spray protection sheath, fire resisting capacity is assessed for each material and installation method according to fire-resistive construction recognition. This study reviews effects of the percentage of water content that exist in fire spray protection sheath during the assess process of fire resisting capacity on fire resisting capacity, and changes of the percentage of water content according to temperature conditions. As a result of exams, as curing temperature is higher and thickness of specimen is thinner, decrease of the percentage of water content becomes significant.
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Technologies on energy saving and materials used in curtain walls have progressed with increase of high-rise and large buildings. This study is explain fire resistance performance of the curtain walls. And focused on bond strength of light-weight inorganic ceramic board in high temperature for fire resistant curtain-wall system. From the result, curtain-wall system high fire resistant using the light-weight inorganic ceramic board.
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Optimum finishing position, thickness and phase change temperature of winter and summer season were selected and suitability of finishing materials was evaluated based on temperature measurement of specimens applying the coating material mixed phase change materials(PCM). As a result, when finishing position was interior and finishing thickness of coating material mixed n-Octadecane(28℃ PCM) was 4mm, thermal performance was effective. n-Octadecane in summer season and n-Hexadecane(18℃ PCM) in winter season are indicated effective on energy savings, respectively.
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The purpose of this study is to develop eco-friendly internal material of acrylic emulsion mortars using light-weight aggregate carrier which contains pyroligneous liquid. Four types of light-weight aggregates (vermiculite, perlite, charcoal, zeolite) that are widely used in building materials are selected and the properties such as adhesion, water absorption coefficient, antibiosis, crack and impact resistance are evaluated in accordance with KS F 4715. As a result, the properties of acrylic emulsion mortars using light-weight aggregate carrier are satisfied with KS requirements. The antibiosis is improved with increasing zeolite light-weight carrier content.
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The various type of polymer such as silicone, modified silicone, polyurethane, etc are being used in domestic construction sealant market. Once sealant is installed in building, it should maintain their specific performances such as preventing moisture, rain, air, etc against environment conditions for several decades. In this study, weather resistance as per polymer type of sealant has been evaluated using QUV accelerated weathering tester. As a result, weather resistance of silicone is highest and modified silicone is lowest in the comparison of other type of polymer.
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In this study, industrial by-products including blast furnace slag, incineration ash and waste gypsum were used with recycled fine aggregates to manufacture the zero-cement mortar.The replacement ratio of dihydrate gypsum and anhydrite gypsum was fixed as 0 and 10%, the replacement ratio fo WA1 was fixed as 0.5% and 1.0%, respectively. It could be identified that when the replacement of gypsum was 10% and WA1 of 1.0%, the strength could be in the range of normal strength.
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This study is intended for the review of the standards related with the released contaminants from building materials used in the building room. Because currently being used industry standard and test method for the emissions of air pollutant are ambiguous so the new enactment and revision of the test methods and standards need to be addressed to match the actual situation in the construction industry. Based on actual evaluation for seveal sealants used in the job site, this study will present a direction for the revision and new enactment of standards and test method appropriately.
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Recently, to ensure the high openness and prospect right of the building, curtain wall system is mainly applied to the high-rise buildings at domestic and overseas. As a result, the use of Structural Sealant is increasing. Structural Glazing Sealant is applied with the glass and AL-FRAME (Mullion) that the strong structural strength is required to hold. However, the structural sealant at the construction site in a variety of external influences, such as wind load, thermal load, uv, chemical pollutants etc, in case of storing condition, if structural sealant stored in high temperature for a long period time, it will not perform well compared with initial performance. In this study, the influence of the performance of one-component structural sealant evaluated for proper storage conditions at the construction site and how to use the non-intended.
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This study is concerned with the root penetration resistance competence and constructability of a waterproofing and root penetration resistance layer of an eco-bridge which is applied with various types of seeding. For the review of root penetration resistance competence, the competence was tested using herbs, woody plants, and tall trees. As a result, there was no tear of or damage to the waterproofing and root penetration resistance layer as well as the sweeping-down phenomenon of a waterproofing and root penetration resistance layer by soil. Also, the effect of the root growth of herbs, woody plants, and tall trees on the root penetration resistance system was confirmed.
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Recently, water treatment facility is usually eastablished in underground, and waterproofing and anti-corrosion materials for concrete structures applied water treatment tank is developing in various ways. However, as the limit of research focused on durability improvement of top coating material, it is insufficient to study on the adhesion strength between the concrete surface and primer. Therefore, there is to confirm the adhesion of between concrete surface and the three primers used as anti-corrosion waterproofing materials, and to investigate the properties of adhesion strength according to the condition such as wet codition and water pressure condition of the concrete surface in this study.
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Recently, waterproof construction used to self adhesive waterproofing sheet in the actual field in winter for reduce cost and term. However self adhesive waterproofing sheet's quality is declined in low temperature condition. So, this study was to confirm on the low temperature condition of concrete substrate effecting the adhesion of self adhesion waterproofing sheet using interface leakage test. As a result of this study, self adhesion waterproofing sheet must not be used at temperature below 5℃. Also, adhesion between waterproofing sheet and concrete is declined in low temperature.
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Recently, it changes to the frame construction in the wall type structure for the life span improvement of the apartment house of our country. The execution of the light panel increased while the execution of the frame construction increased. Therefore, the density and absorption ratio of the magnesium oxide matrix according to the wood flour amount of addition ratio property try to be analyze for the lightweight of the surface material of the light panel. The test result, the density has been declined as the addition ratio increase of the wood flour. In the case of the water absorption ratio, water absorption ratio has been increased as addition ratio increase of wood flour. However, wood flour addition ratio 15% determined the most appropriate when considering the density and water absorption ratio.
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It is well known that the bond characteristics of fiber govern the performance of fiber reinforced composite material. A preliminary study was carried out to investigate the pull-out behavior of amorphous and conventional single fiber in cement mortar in accordance with the JCI(Japan Concrete Institute) SF-8. The test was performed under displacement control, and results showed that the bond strength decreased with increasing fiber length. In addition, the amorphous steel fiber showed much higher pull-out load per unit weight compared to conventional steel fiber.
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The environmental pollution problem the globally related to global warming arises. In the construction industry the cement mostly use material, generates the great quantity of CO2 among the fired process and the global warming is more aggravated. In addition, the polysilicon that is the main raw material used in the solar power generation, produces 1 ton and the industrial by-product of 2 tons is generated. In this way, the arising sludge there is not method recycling and it is all discarded. Therefore, in this research, try to present as the fundamental research material for using the polysilicon sludge as the admixture of the cement in order to reduce the amount of the cement. The based on 'KS L ISO 679' was progressed mortar test. the liquidity, air flow rate, setting time, water absorption ratio, flexural and compression strength was measured. According to, appropriate replacement ratio of the polysilicon sludge tries to analyze.
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In this study, industrial by-products including blast furnace slag, incineration ash and waste gypsum were used with recycled fine aggregates to manufacture the zero-cement mortar. The replacement ratio of anhydrite gypsum was fixed as 0, 10%, 20% the replacement ratio fo WA1 was fixed as 0.5% and 1.0%, respectively. It could be identified that when the replacement of gypsum was 20% and WA1 of 1.0%, the strength could be in the range of normal strength.
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This is an experimental study on manufacturing of non-cement matrix. Materials like cement and blowing agent in foamed concrete is replaced by by-products from blast furnace slag and paper ash. Further, the experiment was performed by replacing alkali with red mud by (0, 5, 10, 15, 25, 35, 45) of weight of alkali (wt.%) in order to reduce the amount of expensive alkali acclerator. Sample Plain with density showed lowest. The compressive strength test result, showed a similar trend with density. And it showed that compressive strength of the RM-0.05 was highest.
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Photocatalytic cement is receiving attention due to its high oxidation power that oxidizes nitrogen oxides (NOx), thus contributing to clean atmospheric environment. However, there has not been a thorough investigation on durability of a parent material, cementitious material, as a result of photocatalytic reactions. In this study, durability of photocatalytic cementitious materials exposed to nitrogen dioxide (NO2) gas was examined. Titanium dioxide (TiO2) nanoparticles containing cement paste samples were exposed to cycles of NO2 with UV light, followed by wetting and drying to simulate environmental condition. The surface of samples was characterized mechanically, chemically, and visually during the cycling. The results indicate that the photocatalytic efficiency decreased with continued NO2 oxidation due to calcium carbonate formation. The pits found from SEM demonstrate that chemical deterioration have occurred, such as acid attack or leaching. In conclusion, the photocatalytic reactions and its product could alter cementitious materials chemically and mechanically which could further affect long-term durability.
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With the recent movement toward sustainable development, many efforts have been made to reduce environmental loads in various domains of industry. In particular, a great deal of research and technology development has been underway on approaches to reducing industrial waste and the emission of greenhouse gases. For this reason, a quantitative analysis of the reduction in CO2 emission that could be achieved by replacing limestone material with cementitious waste powder was performed in this study. Through the analysis, it was found that CO2 emissions were reduced by up to 50 percent compared with the scenario in which OPC was used, which suggests that it is possible to reduce global CO2 emissions by approximately 5percent, or by 446.4 Tg of the 965 Tg of CO2 emissions generated by the cement industry, in the total global CO2 emissions of 19300Tg.
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This study is to XRD and image analysis of low carbon type recycled cement from waste concrete powder and cement raw materials. Waste concrete powder possible to low carbon type recycled cement in small part of additive materials. Also, low carbon type recycled cement using waste concrete powder is suitable for ordinary portland cement.
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This study is a part of development to improve early-age compressive strength of concrete by using industrial by-products. It tried to investigate the characteristics of early-age compressive strength according to curing temperature and industrial by-product replacement ratio 10, 20, and 30 %. As a result, regardless of industrial by-product replacement ratio and age, early-age compressive strength of concrete was found to be high compared to Plain using 100 % cement.
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Concrete made with ground granulated blast-furnace slag(GGBS) has many advantage, including improved durability, workability and economic benefits. GGBS concrete is that its strength development is considerably slower under standard 20℃ curing conditions than that of portland cement concrete, although the ultimate strength is higher for same water-binder ratio. GGBS is not therefore used in application where high early age strength is required. However, hydration of GGBS is much more sensitive to temperatures, the strength development of GGBS concrete is significantly enhanced.
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Modern concrete high safety, constructability and economy due to advantages such as buildings used for more than about 70%, but due to the low thermal performance is essential, such as installation of additional insulation is required, and therefore increase the cost of construction, as well as the construction period and condensation Symptoms such as a domestic environment, such as to inhibit the problem by generating such an improvement has been desired. In this study, we want to present the base line data for the development of improved insulation performance concrete with analyzing and evaluating the Durable Properties of the concrete combination of hollow glass microsphere and lightweight aggregate.
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When press concrete with high W/B was hardened, it should consider a crack to make stress by drying shrinkage. For control of crack, wire-mesh used to reinforce concrete in site. Actually, it reported failure case in lack of quality control. This study conducted experiment to apply fiber reinforced press concrete. it was evaluated on fresh property, compressive strength and shrinkage crack of press concrete with fiber.
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The purpose of this study was to investigate properties of high fluidity concrete adding waste marble powder. A change in the replacement ratios of waste marble powder was measured compressive strength and slump flow, O-Lot and U-Box. Waste marble powder has replaced binder of high fluidity concrete at certain contents of 0~20%. As a results, Slump flow, O-Lot and U-box adding waste marble powder up to 10% have increased by adding waste marble powder. As the concrete with a replacement ratio of waste marble powder up to 10% was found to have a compressive strength superior to that of plain.
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Currently, CO2 existed in the air usually reacts concrete, and then CaCO3 can be appeared. As time goes by, pH of concrete is decreased and corrosion of steel can be happened. This phenomenon is called carbonation. For preventing carbonation of concrete, various methods like using corrosion inhibitor, high compressive strength concrete, and enough covering depth are adopted. But these method are usually passive methods focused on corrosion of steel and have limitation on economic. Thus, as basic study for active method of carbonation, cement pastes with CO2 reactive material (γ-C2S, MgO) and GBFS were in accelerated carbonation, and the compressive strengths were measured. On the result, the compressive strength was improved better than non-carbonation. Through measuring the weight change using TG-DTA, as specimens were carbonated, according to decreasing of Ca(OH)2 and Mg(OH)2, CaCO3 and MgCO3 were increased. Therefore it can be shown that carbonation curing can be realized.
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In order to develop concrete generating compressive strength of 10MPa~15MPa aging for 6hours in the room temperature curing, Hardening accelerator containing Ca2+ mixed with rapid hardening portland cement containing C3S in quantity. The result was that the more addictive contents of Hardening accelerator is, the more greatly early compressive strength was improved. That's because the composition of Ca(OH)2 was mass-produced at early-ages.
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In this study, a replacement ratio of blast furnace slag coarse aggregate and a water binder ratio by an optimum combination of PHC file was investigated. As a results, the target strength 78.5MPa was altogether satisfied in a mix proportion 28-G100-SG0 and W/B ratio 26 %. The surface rupture was generated in 28-G0-SG100 combination after curing with the autoclave. According to the result of measuring the ingredient, the majority were the MgOH2 hydrate.
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Existing the free-form concrete segments (FCS) mold is produced by state of solid such as steel, wood, Styrofoam that can not be recycled. Using FCS mold result in delay on schedule and decrease of productivity because it consists of irregular curved variety and it requires more time than fixed mold. Thus, FCS mold should be developed which can reduce the costs and also it can be used as semipermanent. The aim of this study is to suggest of flexible mold production process for using the phase change materials(PCM). PCM is maintain that its solid state at low temperature but it changes phase to liquid state by heating. PCM is suitable material for flexible mold due to change of phase in relatively high temperature compare to other phase change materials such as water. Flexible mold is possible that reuse semi-permanently made by PCM. Thus, this study is proposed the process of flexible mold production for using the PCM. The study results will be used as the basic theory for studies on production and installation of FCS.
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As the increase amount of high rise building, equipments for high rise building have been extensively studied. However quality problems caused as the pumping of concrete including loss of flowalility, air content and increasing of the temperature. In this study, fundamental performances of the 80 MPa concrete before·after pumping has been tested. Results showed slump flow increased after pumping temperature of concrete also increased after pumping. Results also shown air content all satisfied the target range and compressive strength of concrete increased about 20 % after pumping, All the performances satisfied the standard for 80 MPa.
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Recently, carbon dioxide emissions have increased in succession according to the development of industry. also, cement of construction materials is being increased carbon dioxide during the manufacturing process. it is predicted that amount of carbon dioxide will be produced about 10 % in the world. as a way of solve this problem, it is used to reduce the amount of cement and to replace cement using industrial by-products such as blast furnace slag, fly ash, and red-mud. but, these are not advanced in our country. Thus, the purpose of this study is to analyze the strength property of binary blended geopolymer concrete. So, this study carries out the basic performance test of concrete such as, slump, air content and compressive strength.
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This study was performed an evaluation of mechanical properties of reactive powder concrete using copper slag. So, various RPC containing copper slag were made by replacement ratio of copper slag and different the curing condition and their mechanical properties were investigated. From the experimental results, slump flow using copper slag tends to increase with replacement ratio. And also, 30% of copper slag with quartz sand was found to have a compressive strength superior to that of plain.
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Recently, it is certain that the increase of heating and cooling energy consumption by radical change in climate condition has caused serious problems related to environmental and energy concerns associated with increase of fossil fuel usage and carbon dioxide production as well as global warming. Therefore, various actions to reduce greenhouse gas and energy consumption have been prepared by world developed countries. The energy consumption by buildings approximately reaches 25% of total korea energy consumption. The greatest part in the buildings of the energy consumption is building facade. But a few research projects on concrete comprising more than 70% of outsider of buildings has been tried. This research is structural insulation concrete what improved insulation performance using micro form admixture and calcined diatomite powder and lightweight aggregate.
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An active study on UHPC, which has been recently used in high-rise building and bridges, is in progress. However, research on adhesion strength of normal concrete and UHPC is required to be studied due to the lack of information. In this study, experimental research progress for adhesion strength (shear strength of adhesive surface) evaluation of Bi-compressive strength concretes (UHPC, Normal concrete) is proceeded. First, specimens using glue are produced and surface treatment methods of concrete bonded section are considered. Second, Direct Shear test is applied on concrete bonded section of UHPC (80~180MPa) and Normal Concrete (NC). As a result of this study, it is confirmed that bond strength is deteriorated as the difference of intensity ration of NC and UHPC increases.
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In this study, effects of pore structure of ground granulated blast-furnace slag concrete on freezing-thawing resistance are reviewed. As a result, degradation of freezing-thawing resistance performance was occurred as replacement ratio of ground granulated blast-furnace slag increases under same specified concrete strength condition. It is considered that pore structure of internal binder affects freezing-thawing resistance performance.
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Performance degradation of Ultra High Strength Concrete occurs more than that of normal strength concrete at high temperature. Thus, strain of concrete subjected to high temperature and loading is one of the core assessment items for evaluating performance of structures. Therefore, in this study, creep of ultra high strength concrete subjected to various temperature conditions and 25%, 40% loading was evaluated. As the results, Creep strain increased with increase of temperature and loading. Creep strain of concrete at high temperature is influenced by loading.
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The purpose of this research is to examine strength properties of epoxy-modified mortar with expansive and swelling agent contents. The polymer-modified mortars (PMMs) using epoxy resin are prepared with various polymer-binder ratios, expansive and swelling agent contents. The PMMs using epoxy resin are tested for compressive, flexural and tensile strengths. As a result, the strength properties of the PMMs using epoxy resin are depending on the polymer-binder ratio rather than expansive and swelling agent content, and are remarkably improved over unmodified mortar (UMM).
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Many project (such ESCO or BRP) are being implemented for existing building energy saving. Most of medium or large building that use many energy being implemented this project. In the case of large or medium building must implement obligatorily Energy auditing. Therefore, They can be recognize their building energy consumption situation. But, In the case of small building don't need obligatorily energy auditing. Therefore, They can't be recognize their building energy consumption situation. As a result, Small buildings are difficult to participate in energy efficiency retrofit. In this research, Building owners of buildings energy load recognition and energy efficiency retrofit possible participation was analysis though survey. Survey results, Most building owners don't know building energy load. But they have a good mind to retrofit building energy efficiency. As a result, If they have energy load information, they will be participate energy efficiency retrofit.
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Recently, it is becoming necessary for architectural heritage to make spatial information structure by using BIM(Building Information Modeling). However, current BIM system can not be used because its information classification and structure is not suitable for architectural heritage. This is a basic study which focuses on upgrading spatial information structure of BIM so that it would be possible to use BIM in management of preservation of architectural heritage, too. This study analyzes Sungnyemun case and its spatial information structure.
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United Nations Framework Convention on Climate Change(UNFCCC), an international treaty to prevent the regulation and global warming, has passed through the General Assembly for 17 times from 1992 to 2011. To create a performance plan specific, such as the Kyoto Protocol, it is to promote the reduction of energy consumption and greenhouse gases worldwide. In South Korea, Korea Infrastructure Safety and Technology Corporation(KISTEC) is working and supporting for developing method of green remodeling policy. Among several solutions, "Remodeling" ensures to increase the energy efficiency of buildings and to reduce the emissions of greenhouse gases, and consequently it could maintain buildings high efficiency. For remodeling projects, it is most important to determine construction plan including remodeling scopes and methods, while the plan has been determined by the engineer's background and experience. Therefore, this study aims at developing a method for selecting optimal skin system which has remarkable influence to energy performance of the buildings.
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As a governmental plan for real estate revitalization, remodeling vertical extension has been permitted. Thus, the Ministry of Land, Infrastructure and Transport preannounced proclaiming the revised Housing Act and establishing the remodeling basic plan, and it is anticipated that the remodeling market will be revitalized in earnest after the enforcement of remodeling vertical extension(April 25th. 2014). As vertical extension is applicable up to 3 stories, the safety of building for remodeling is becoming important, so most remodeling construction works use various methods for structural reinforcement. In this process, the selection of structural reinforcement method has depended on structural engineer's experience and knowledge and there has been a limitation in selecting the optimum structural reinforcement method which considers remodeling project characteristics. Therefore, this study analyzed the factors to determine the kinds of structural reinforcement method in a remodeling project and suggested a process to select the best structural reinforcement method of remodeling construction.
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Measurement of beam deflection is a common procedure to determine proper behavior of the structure. Either LVDT (Linear Variable Displacement Transformer) or strain gauge is usually used in experiments. A newly developed coordinate reading measurement system can be also applied for the deflection measurements. In this study, an experimental measurement was made on a laboratory size beam specimen to examine the possibility of the use of such coordinate measurement system. Results have shown the possibility of utilizing the new system for beam deflection measurement.
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The green building certification criteria in detached houses in 2012 and it included in the green building certification subject. However, the green building certification result of the detached houses is slight after revising of the system. Therefore, in this research, we were performed the importance analysis for the green building certification assessment of the detached houses. The results of this study will contribute to the green building certification work.
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New and Renewable eco-friendly energy technique can be to enable rational use of resources, as well as securing economic efficiency. Therefore, most of the public facilities must apply eco-friendly energy systems. In this study was applied the solar light energy system to the construction projects. As a result, the proposed system was implemented various effect such as the power cost savings in public facilities. In addition to, the proposed system was improved functional aspects such as improving space utilization.
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Green building technology has the potential a competitiveness. Reflecting this situation, the renewable energy market is growing rapidly. And, this field became value-added field in construction industry. In this study perform to prioritize the value improvements of green building technologies. To do this, first, we will extract potential development field through literature and case studies. Next, we will built a hierarchy structure based on the economic efficiency, technical skill, and policy. Third, we decide to prioritize between the items by performing AHP analysis.
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A lot of very complex free-form buildings such as Seoul City Office and DDP(Dongdaemun Design Plaza) have been recently built nowadays in domestic. However, as construction methods and cost data are decided without enough discussion and collaboration with specialized subcontractors during design stage, construction quality problems and cost overrun of the free-form buildings are thus occurred during construction stage. Therefore design system and process or contract and ordering system should be developed participating the specialized subcontractors during design stage in order to perfect the free-form design and construction. Especially US has thus an effort to apply IPD(Integrated Project Delivery) system which can solve the problems of construction quality, productivity decrease and cost overrun by constructing the buildings based on exact drawings and collaboration as well as activating BIM(Building Information Modeling). Therefore this study reviews cases of the free-form buildings in domestic and then presents necessity review of IPD in domestic.