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
2019.05a
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Smoke and fire spread throughout the building as a result of problems in the fire prevention section of Uijeongbu Apartment Fire in 2015 and Jecheon Sports Center Fire in 2017 in Korea, causing a number of casualties. It is believed that the fire compartment standards need to be reviewed as the fire in recent buildings continues to show problems. In this study, a comparative analysis was conducted on the fire prevention zone standard with Japan to improve the fire compartmente standard in Korea.
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In order to solve problems such as scattered dust, dust and chemicals harmful to the human body, workability in a confined space, quality performance, and the like generated during the field construction of the conventional waterproof sheet construction method, a waterproof sheet is used as a PC formwork, Which is produced by pouring concrete after PC installation, and evaluating the applicability of the development method in comparison with the construction method of polypropylene waterproof sheet construction method and the construction period, safety, quality, construction cost.
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Euro forms and aluminum forms, which are currently used in formwork construction sites are limited by their heavy weight and the use of environmentally hazardous form oils. Therefore, in this study, 'eco-friendly light weight form' was developed, which does not require form oils during the removal process of form. In addition, the superiority of the developed form was verified by comparison with Euro forms and aluminum forms in terms of noise generation and weight. Application of the eco-friendly light weight form in construction sites is expected to reduce the noise level, and increase workers' convenience. The productivity of formwork is also increased.
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Interior stone walls are using commonly in non-bearing lightweight walls of apartments. The stones of interior wall were two types, one is a granite stone, another is a marble stone. Granite stone is attached by the epoxy adhesive and marble stone is attached by dedicated anchor and fastener. The impact resistance test was carried out interior stone walls in accordance with KS F 2613. The test methods included the impact resistance tests by each of soft impact body and hard impact body. The results of the test have proved that interior stone walls can withstand the soft impact bodies and hard impact bodies that are likely to happen in everyday life.
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The bearing capacity of the wall against the eccentric load when the washbasin was attached on the ALC block wall was tested. Test methods are BS EN 14688 and BS 5234-2. Tests in accordance with BS EN 14688 showed that the holding capacity of steel was much stronger and more stable when HA-II (chemical anchor) was used than when the washbasin was fixed using HA-I (plastic anchor). As an experimental result according to the Annex K of BS 5234-2, the bearing capacity of ALC block wall corresponded to the "stage in which the force works(performance grade) 1,500N" for all of the cases where a washbasin is fixed using two types of the wall's dedicated anchors(HA-I and HA-II).
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The demand for drywall is increasing as the structural type of apartment building is changing to a rigid frame structure. At present, the thickness of the gypsum board used for drywall is mostly 9.5mm and is required to be changed to 12.5mm to improve the performance of the wall. A structural safety test has been conducted in accordance with KS F 2613 to verify the effect of changing the thickness of the gypsum board to 12.5mm in terms of improvement as to stiffness. As a result of the test, the stiffness of the drywall has increased by about 19.6% and the impact resistance by about 30.4%.
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In this study, the initial strength reduction of coal gasification slag fine powders was confirmed through previous studies when used in cement formulations. It is also confirmed that the blast furnace slag is mixed with cementitious coal blast furnace slag, which is similar to coal gasification slag, to incorporate gypsum in order to prevent initial strength deterioration. In order to analyze the reactivity of coal gasification slag by desulfurization gypsum, the formation of hydrates and their reactivity at early ages were confirmed by electron microscope. In order to confirm the reactivity, the gypsum samples were prepared with unincorporated type and 2% mixed type. Experimental results showed that 2% of the desulfurized gypsum specimens reacted more actively than the uninjured ones.
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The purpose of this study is to apply a test method that evaluates durability under wet environment rather than the strength of the material itself to reflect the environment of use and field conditions of silic acid powder applied waterproof material, and to prepare a foundation data for differentiated performance criteria through test verification.
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This study is designed to apply natural clay replaceable redmud as ceramic material by mixing redmud with the materials used in existing brickmaking in laboratory environment. Therefore, through this study, the redmud is recycled as a raw material for clay bricks and presented as a basic material for the use of redmud in clay bricks.
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In this study, analysis of steel fiber orientation and distribution inside fiber reinforced concrete was performed using micro-CT scanning technology. Samples were extracted from the column according to its height and distance from the mold. Samples were scanned in order to attain the image of steel fibers then region of interest were obtained by binarization process. By calculating the principle moment of inertia of each fiber, direction vector, scale, center postion, volume, and surface area were gained in order to analyze the orientation and distribution. Most of the fibers inside the column tended to be perpendicular to the main axis of the column. Moreover, most of the fibers appeared at the bottom of the column and at the position where it is farthest from the mold.
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The construction of adobe houses in flood prone areas is a common practice. These houses collapse when hydraulic loads from flood exerts on the houses. The failure occurs because the adobe brick lacks strength. In order to improve strength of adobe brick, the effects of agriculture waste therefore rice straw, rice husk and rice husk ash as a stabilizing agent have been explored in this paper. The compressive strength test and splitting test was conducted on the adobe specimens which were stabilized with 2% rice straws, 2% rice husk and 2% rice husk ash by the dry weight of soil. The results showed the improvement in strength and elasticity of specimens containing rice straws & rice husk. Whereas with the addition of rice husk ash, the adobe loses its strength and showed plastic behavior.
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Recently, a bed company detected a radon more than Red Politics and became a hot topic of conversation. This has led to increased interest in radon, and a number of free-of-charge bodies have also been established to recognize the dangers of radon. In addition, the Korean Institute of Geological and Resource Research is planning to assist the installation of radon alarm systems in 10,000 households nationwide, free of charge. Since radon is a colorless, odorless and tasteless gas that causes lung cancer, it aims to reduce lung cancer incidence by absorbing radon using bamboo activated carbon as a way to reduce it. Due to the use of bamboo activated carbon, radon concentration per hour tends to decrease as substitution rate increases, and table flow tends to decrease as substitution rate increases. Through this experiment, 30% of the replacement rate of bamboo activated carbon is judged to be the most suitable replacement rate.
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Carbonation of the root concrete reduces the durability of the reinforced concrete, and it is important to check the carbonation resistance of the concrete to ensure the durability of the reinforced concrete structure. In this study, a basic study on the prediction of carbonation progress was conducted by considering the mixing conditions of concrete using deep learning algorithm during the theory of artificial neural network theory. The data used in the experiment used values that converted the carbonation velocity coefficient obtained from the mixing conditions of concrete and the accelerated carbonation experiment into the actual environment. The analysis shows that the error rate of the deep learning model according to the Hidden Layer is the best for the model using five layers, and based on the five Hidden layers, we want to verify the predicted performance of the carbonation speed coefficient of the carbonation test specimen in which the exposure experiment took place in the real environment.
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This study evaluated the effect of amorphous steel fibers on the spalling characteristics of high-strength concrete. with mix proportions of polypropylene (PP) fibers of 0.15% by concrete volume, and proportions of amorphous steel fibers of 0.3% and 0.5% by concrete volume. In the range of 0.3 vol% of amorphous steel fiber, the effect of suppression of the spalling and the prevention of degradation of strength was shown, but it was evaluated to be ineffective in the suppression of the spalling due to interferences in formation of pore network in the range of 0.5 vol.%.
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In recent years, the construction industry has also applied the dry method that can be assembled in the field by industrialization and factory production, which is free from climatic effects and can reduce the cost due to mass production and simplify the work in the field. Among the building materials used in this dry method, ALC products are made by mixing calcium oxide, gypsum, cement, and water in silica and putting them in an autoclave to create voids in the interior through steam curing at high temperature and pressure. But it requires curing cycle conditions of warming, isothermal, and temperature curing. It depends on the performance of the product depending on the curing conditions, the economical efficiency due to high oil prices, the emission of greenhouse gases by the use of fossil fuels. Experiments were conducted to select an appropriate animal protein foam for lightweight foamed concrete block which was cured by applying a prefilling method to replace existing ALC products. As a result of investigating the characteristics of lightweight foamed concrete by type of animal protein foam, it is considered that FP3 is most suitable for manufacturing lightweight foamed concrete block.
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In domestic construction industry progress, construction and quality control of large structures are considered to be important as the superstructure and mass scale of structures. In the case of mass concrete, high hydration heat caused by cement hydration generates temperature stress by generating internal temperature difference with the concrete surface. These temperature stresses cause cracks to penetrate the concrete structure. A method of lowering the heat generation by incorporating Urea in order to reduce the concrete temperature crack has been proposed. In this study, the heat function coefficient for the FEM temperature crack analysis of the mass concrete containing the element was derived and the adiabatic temperature rise test was carried out according to the incorporation of the element. As a result of this experiment, the maximum temperature of 41 ± 1℃ was obtained irrespective of the amount of urea, and the maximum temperature decreased by 16.9℃ in concrete containing 40kg/㎥ of urea.
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Mechanical properties of concrete containing furnace slag according to the CBS Dust Replacement Ratio were analyzed. The experimental study found that the compressive strength was excellent in the early age when the CBS Dust was replaced, and the drying shrinkage was excellent, and the replacement of CBS Dust 5% on the concrete containing the furnace slag would have a positive effect.
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Fine dust, which is emerging as a global problem, attracted much attention recently in Korea. One of the reasons is that recent factory relocation and expansion in China affected the increase of domestic fine dust concentration due to the influence of the Yangtze river battalion and westerlies. Fine dust is a big problem not only in outdoor but also indoors. The room requires periodic ventilation and is also essential for improving indoor air quality. The fine dusts are designated as Group 1 carcinogens in WHO and the risk of fine dusts on the human body due to respiratory diseases is also increasing. In this study, the characteristics of the fine dust adsorption matrix are examined and the actual application direction is derived.
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Major construction projects will be directly related to construction costs and disclosure period depending on the selection of the construction method. However, there are some sites that choose without taking into account sufficient conditions. Therefore, the company wants to present a quality model that suits the characteristics of major engineering fields.
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Accident rate in domestic construction industry has been increased rapidly in every year. In particular, the rate of death has been shown very high compared with other industries. It means that safety activities performed by government is not effective in reducing the rate of accident. To solve these problems, the risk factors should be predicted in advance, controlled, monitored and managed from start of project to end of project. However, most studies have been conducted by using frequency of occurrence of accident and only listed the importance of risk. Therefore, the objective of this study is to provide basic material to develop risk quantifying model for human accidents on construction site in South Korea. In the future, it is expected to be used as a reference of study on developing safety mangement checklist in construction industry and model for forecasting accident.
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Currently, the government has made a lot of efforts to improve construction productivity but there are few studies which measure between safety perception level and productivity in the South Korean construction industry. Therefore, the objective of this study is to analyze correlation between safety perception level of domestic construction companies and construction productivity. To achieve the objective, first, the concept of safety perception level was defined. Second, the safety perception level and construction productivity were investigated in the case projects. Third, correlation analysis was conducted between safety perception level and productivity. As a result, it was concluded that a high level of safety perception of executive and manager would increase construction productivity. In addition, To improve the safety perception level in the construction company, it is suggested that the provision safety resources for managements and the equal communication system between workers and managements and the development safety education tools considering the worker's experience. In the future, these findings can be utilized to develop future evaluation tools for a safety perception level in domestic construction company.
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In the case of High-rise buildings, it has a problem by stack effect that rise of vertical height. Especially in case of fire, it need to the consideration of stack effect that it has bigger than general. Therefore in this study, we used to the Contamw and FDS simulation for analysis of stack effect and pressure distribution characteristic in fire. As a result the Contamw simulation shows the pressure distribution by stack effect in general high-rise buildings. However, in case of fire, the height of the neutral plane is lowered and stack effect is larger. Therefore, it is necessary to multiply analyze the temperature distribution and the stack effect in fire.
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Currently in domestic, it is difficult to the evacuation in fire due to the building is higher. Therefore it is necessary to evacuation safety design of building. To conduct the evacuation fire design of building, it should be done the Evacuation Safety Verification. But it is not sufficient the Study about Evacuation Safety Verification in currently domestic. Therefore in this study, we conducted the evacuation safety verification using people who they can't the evacuation themselves. The method of verification, we suggest the comparative that people who they can't the evacuation themselves and available safety evacuation time. Available safety evacuation time is determined by determined method from disaster statistics of casualties or equivalence with current standard requirement. it is doing to objectively judge of evacuation safety design validity in building.
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Currently, the market for free-form building continues to grow, but the technology for construction of free-form building in Korea is still in need of much study. In this study, we focused on this problem and conducted basic study for development a side formwork control system to product various types of FCP. As a result of this study, it is expected that it will be able to secure competitiveness for the free-form building market, which is expected to contribute greatly to the growth of the construction industry.
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Precast concrete finishing panels can be implemented in different colors, textures and designs relatively freely by different designers in different finishing materials. Therefore, we tried to develop a PC finishing panel that can be applied in the field by using various color pigment and concrete surface retardation method and polishing method.
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A Study on Life Cycle Cost Analysis of Thermal Bridge Barrier Between Window Frame and Concrete WallThermal bridge on a building envelope causes additional heat loss which increases the heating energy consumption. As the higher building insulation performance is required, heat loss through thermal bridge becomes higher proportion among total building heating energy consumption. For the exterior insulation and finish system, thermal bridge between window frame and concrete wall should be constidered as one of main reasons of heat loss. In this study, the thermal bridge barrier between window frame and concrete wall(STAR) was proposed as the best practice for reducing thermal bridge. The STAR was confirmed that the use of thermal bridge barrier imporved the annual heat energy capacity by 35% or more and the innitial construction cost by 7.4% or less because of additional interior insulation against condensation. Finally the life cycle cost during 20 year by heating energy of a building reduced by 25% or more compared with the exist technology. This STAR thermal bridge barrier will be used as the main technology to improve the energy efficiency of building.
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With development of IT technology, the ubiquitous has been realized in various industry. In construction industry, as well, end-edge techniques have been introduced such as managing technique the temperature and compressive strength of the concrete placed in structure in domestic and abroad project sites. However, several problems were found during application at the actual field regarding difficulties of connecting Bluetooth communication due to the short communication range, diffuse reflection caused by aluminum formwork, and high cost by using one-time sensor. Therefore to recover these shortages, and improve the performances, the wireless sensor network based concrete IoT management system for concrete early-age quality management was developed.
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Due to the rapid deterioration of the domestic atmosphere, people are suffering from inconveniences such as wearing fine dust masks all the time during outdoor activities. In this study, light transmitting concrete, LEFC(Light Emotion Friendly Concrete), using TiO2 photocatalyst was produced. Since the characteristics of LEFC where acrylic rods are inserted require self-consolidating performance, the purpose was to utilize UHPC(Ultra High Performance Concrete) materials to obtain high-flowability. Further, the compressive strength and flexural strength were evaluated to prevent the reduction of epidemiological performance by utilizing UHPC materials. As such, a basic study was carried out to develop LEFC materials using photocatalyst that can purify the air and stimulate human sensibility.
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In this study, flexural strength and impact resistance were evaluated to investigate the fiber length effect of amorphous metallic fiber. As a result, in the case of 30AFRCC, cutoff behavior due to excellent bonding performance by large specific surface area has greatly influence on the flexural and impact resistance performance. In the case of 15AFRCC, the bonding efficiency is relatively low, because the specific surface area is smaller than that of 30AFRCC and the number of fiber is large, so the effect of improving the flexural and impact resistance performance is smaller than that of 30AFRCC.
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The mechanical and durability characteristics of concrete structures depend on the construction environment, material conditions, design conditions, and temperature and humidity environment after casting. However, wired communicati-on sensors which are mainly used in the field have many limitations in their usability and monitoring. In this study, all temperature and humidity data measured from embedded sensors are monitored via a wireless sensor network. Based on the measured temperature data, the predicted compressive strength of the concrete was compared with the actual compressive strength. As a result, The error between predicted strength and experimental strength has decreased over time.
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Glass fiber reinforced concrete (GFRC) is very suitable as a material for free-form concrete panels (FCPs) because of its lightweight, strong, moldable, durable and sustainable properties. GFRC is superior in construction and maintenance compared with materials such as steel, aluminium, titanium, glass and plastic, and is advantageous in cost. However, GFRC is being produced by skilled craftsmen, and still lacks the technology to economically produce high quality FCPs. Currently, there is a technology to automatically and accurately produce FCPs. However, the developed technology can not be applied to the field with simple production technology without production line for mass production. To solve this problem, the purpose of this study is a basic study of production system development of free-form concrete panels. This study introduces the developed FCPs production technology and builds FCP production system for mass production. The results of this study will be used as basic data for the commercial production of FCPs in the future.
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As the physical functions of school buildings and the changes in the functions of educational facilities due to social change are increasing, the demand for fundamental and long-term measures for the maintenance of educational facilities is expanding. However, depending on the function of the facility, the maintenance work has been carried out only when it is directly related to the safety problem, or when the request of the school facility manager is requested, rather than supporting preventive maintenance. In this study, we investigate the maintenance process of educational facilities and propose a method to manage the maintenance process of the educational facilities in the unit of space for establishing an efficient maintenance management system.
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There are certain types of construction that produces many defects during the construction of apartment buildings. It may be due to construction errors in the type itself, but more often, it is due to defects derived from other types of construction. Thus, to reduce such secondary defects and prevent fundamental defects in particular types of construction, academic research on the types of construction causing secondary defects should be actively conducted. In addition, as claimed in this study, the industries should work harder to improve the quality of the type of construction that causes secondary defects, rather than just trying to improve the ostensible problems. If the efforts of each sector are backed up, the disputes over defect repair in apartment building construction will reduce in general, which in turn will lead to a reduction in national loss within the construction industry.
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Currently, there is a lack of studies on the directionality of architectural engineering education. This study has analyzed the opening and operation of courses relating to building construction in Korea universities. It was researched that the most common building construction courses opened in universities were 'building construction' and 'materials.' Courses are also being opened in universities by reflecting social demands. Upon analysis of the operation of the educational process of building construction, it was displayed that projects and examinations were conducted as the methods of assessment in courses at many universities. Additionally, there were universities that included quizzes and discussions in their methods of assessment. This study is expected to be used as data for studying an innovative means of educating architecture.
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A construction project with a total construction cost of over 10 billion KRW should be evaluated whether construction works are appropriately executed. The evaluation is carried out on quality management, process management, construction management, safety management, environmental management. The implementation period is within 60 days after completion of construction of the construction, from the time when the construction rate of the construction work has progressed by more than 90% to the construction cost. However, the participating construction engineers should prepare the evaluation within the period according to the evaluation criteria, but there are difficulties in preparation for the evaluation due to the reasons such as the change of engineers in charge and loss of data. Therefore, this study proposes the procedure of construction evaluation and adjusts timing of construction evaluation.
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Change requests occur persistently in the construction phase of a construction project. The law requires that the contract amount be adjusted in accordance with the relevant regulations when there is a change in the construction amount due to the design change in the construction contract. SAVE international, on the other hand, defines the value methodology as a systematic and structured approach to improving projects, products and processes. Design Changes in the construction projects require organizational efforts to improve value and quality. However, the law does not include change requests in which the VE object is fixed and related data is collected and function analysis can be derived in a short time. Therefore, it is necessary to apply VE to the design change procedure, which can further improve the value of construction work. The application derived from this study need to be presented as simply as possible without compromising the basic concept of VE. If the application is extended to the field and proved to be effective, it is expected to contribute to the overall value of construction work.
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Free-form buildings refer to geometric external structures in curved form, unlike conventional structures with straight lines. The development of construction technologies for the implementation of these Free-form buildings is ongoing. However, there are still many restrictions on the construction technology of Free-form buildings, resulting in problems such as increased construction period and increased construction costs. Therefore, it is urgent to develop building technology for the construction of Free-form building in order to secure competitiveness in the global Free-form building market. Accordingly, this study proposes Two-sided multi-point press technology that can solve problems of existing technology and implement FCP(Free-form Concrete Panel).
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Recently, the educational facilities were 45% among total damaged facilities from the Po-Hang earthquake. Consequently, the seismic reinforcement of existing educational facilities were ended up attracting people's interesting. However, research is insufficient to consider that how far technology has been developed. Therefore, the purpose of this study is to investigate the level of domestic guideline research by comparing to foreign guidelines in regard to seismic reinforcement methods applicable to existing educational facilities. To achieve the objective, first, the current status of seismic reinforcement projects in domestic educational facilities was analyzed. Second, the domestic and foreign seismic reinforcement methods guidelines for structural, non-structural was compared. Third, the improvement directions for future guidelines were suggested. As a results, the improvement directions of domestic seismic reinforcement methods guidelines were proposed. First, the structural seismic reinforcement strategy needs to be segmented. Second, it is necessary to analyze about non-structural guidelines based on additional cases. In the future, this study can be used as a basic material for developing seismic reinforcement methods guidelines in domestic existing educational facilities.
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In case of Korea, The Large-scale fire is consistently being such as 2015 Uijeongbu Fire, 2017 Jecheon Fire, 2018 Sejong Hospital Fire. Such a fire has a problem that the fire is spreading upper due to external flame spread. As a countermeasure the fire safety, the study about axial temperature prediction of external flame spread is consistently doing. But in korea, Vertical spandrel is specified as 40cm, and improvement is urgently needed. In this study, a repair material was selected to prevent the fire from spreading to a building where a flammable exterior material was installed and then pilot construction was carried out. Also, fire safety measures for buildings constructed with flammable exterior materials were examined.
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The purpose of this study is to clarify the difference between design and construction conditions based on theory for support (S) and infill (I) distinction and separation in long-life housing, and to search for future direction. To do this, the SI theory is summarized and the construction situation is examined in the demonstration house and the differences and limitations are analyzed. In order to realize SI separation in Korea, it is necessary to set the position of pipe shafts for sewage and drainage, buried in the structure and Ondol layer of the private pipes, buried various wires in the inner wall, and fixing the position of the inner wall.
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In case of fire in a compartmentalized building area, a number of casualties are caused by smoke production. Accordingly, openings, penetrations and joints in compartmentalized spaces should be secured not only for fire resistance but also for smoke-proofing. However, domestic test regulations stipulate test methods for refractory performance of penetrations and joints, but do not specify separate deferral performance. In the case of openings, the test for the smoke performance exists at room temperature, but the smoke performance at high temperature is not secured, so countermeasures are needed.
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When the fire door is recently installed in the field, there are frequent cases where the fire door is manufactured with fire door having low quality or different structure compared to the performance that the fire door producer has confirmed in the performance test or the construction specification. In order to improve the on-site quality management of the fire door, we comprehensively classify the quality management items of the fire door according to the management subject and the step by stage and set the field quality management procedure, the field quality management inspection item, regulations and standardized checklists were presented.
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In this study, fire resistance test according to KS F 2257-8: 2015 was carried out to compare fire resistance for wall consisted of gypsum boards with two types of drywall with gypsum boards which is based to lightweight studs. As a result, it was found that the fire resistance of the wall constructed with 12.5 mm of general gypsum board was 16 minutes higher than that of the wall constructed 9.5 mm in accordance with integrity and was 9 minutes higher than that of the wall(9.5 mm) depending on insulation. If the wall with the gypsum board 12.5 mm is constructed, it can be confirmed that the fire resistance is improved by about 43%.
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Water repellent and waterproofing agents fail to act work properly if cracks or detachment occurs outside. The method of making mortar was tested by classifying it into two methods: direct water-repellent put in concrete and water-repellent spray to sand method. It was found that the compressive strength was decreased as the amount of water repellent was increased. As a result of measuring the contact angle, all of the specimens were hydrophobic. The spray method showed greater water repellent effect than the direct mixing method.
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The use of high fluidity concrete has been added in recent construction work. In this study, we analyzed segregation resistance due to admixture substitution of the system high fluidity concrete that was hardened. The research results show that the resistance to segregation at the time of admixture replacement is improved. The best results were shown with a ternary system mixed like FA and BS.
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The aim of the research is assessing the possibility of recovering the compressive strength of the mortar mixture replaced excessively high volume of blast furnace slag accidently. As a result of the experiment, in the case of compressive strength, painting sodium oxide showed higher compressive strength recovery effect than painting calcium oxide. As a curing temperature, 20℃ showed advanced result rather than 65℃. From the wet curing, the reaction was confirmed, deeper penetration depth was checked at 20℃ than 60℃ temperature. Therefore for the concrete mixture with excessively high volume of blast furnace slag, it is considered that painting sodium hydroxide and curing 20℃ can recover the compressive strength effectively.
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In this research, considering the practical conditions at field, thermal cracking method was suggested based on the comparative analysis between predicted value and actual value obtained from the actual structure member with optimum mix design. The optimum mix design was deduced from the various mix designs with various proportions of cementitious binder for upper and lower placement lifts of mat-foundation mass concrete. Therefore, it can be stated that applying low heat mix design and different heating technique between upper and lower placement lifts for mass concrete are efficient to control the thermal cracking. As future issues, based on the interpretation result value, we will select the optimal combination that is applied specifically to the actual site, and deeply analyze the correlation between the measured value and the analysis value through the combination and the test of the actual structure.
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The interlayer noise of the apartment house is a typical problem that reduces the quality of the residential environment. Therefore, many researchers have developed soundproofing materials that blocks noise between floors. However, most development technologies do not have the noise cut-off effect felt by residents, and may also have a defect in long-term deflection. In this respect, this study developed high-performance interlayer soundproofing material that can overcome existing problems. The developed technology has the noise reduction effect experienced by the residents and it has high durability without long-term deflection. Therefore, high-performance interlayer soundproofing material is expected to contribute to reducing disputes over noise between floors of apartment residents.
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Concrete with high thixotropy has a lower plastic viscosity when pour in, thus demonstrating fluidity, and After poured, the viscosity can be restored again to ensure stable progress without additional liquidity and material separation. Therefore, in this study, a basic study of thixotropy of concrete was proceeded through cross-linked bond of PVA and Borax. Therefore, it is judgment that the higher the concentration of boron solutions, the higher the strength of the interconnections between PVA and boron.
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Recently, supplementary cementitious materials such as blast-furnace slag, fly ash and silica fume have been widely used as substitutes for cementitious materials. In this study, the deformation behavior of compressive loading of C3S paste with 50% fly ash was analyzed by X-ray scattering data and pair distribution function analysis. The obtained results were compared with 131-day-old pure C3S paste. The Ca(OH)2 of the C3S-FA paste showed almost complete elastic behavior, consistent with the deformation behavior of the r-range of 20 to 40, and the C-S-H phase contributed to the range of PDF r-range of less than 20. In addition, C-S-H of C3S-FA showed greater deformation resistance than C3S paste.
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When concrete is exposed to fire, the decomposition of Portland cement paste results in critical damage to the concrete structure of a building. Although the behavior of cement pastes after heating provides crucial information with respect to the reuse of the building exposed to fire, the recovery process of the damaged concrete structure has not yet been fully elucidated. In addition, research on appropriate additives such as carbon nanotube (CNT) has been increasing recently, however, investigation of CNT incorporated cement paste after decomposition of CNT by high temperature is not fully investigated. In this study, we investigated the physicochemical properties of CNT incorporated cement paste under different temperatures (200℃, 500℃ and 800℃). Also, the effects of different rehydration conditions (20℃ 60% RH and in water for different curing times) on the recovery of the paste were studied. The changes in tensile and compressive strength, surface observation of the specimens were characterized. In addition, the decomposition and formation of hydrates in the paste due to the heating process were studied using X-ray diffraction.
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3D printing technology can be applied to various industries, and is trapped by major technologies that change existing manufacturing processes. 3D printing materials must satisfy designability, economy and productivity, and building materials are required to have strength and economy secured technology. 3D printing technology of construction field can be divided into structural materials and internal and external materials, and is mainly done by extruding and adapting. Particularly when it is applied as an exterior materials, it is mainly applied to an unstructured exterior materials and high accuracy is required. The exterior materials can be used as a cement composite materials, it is suitable also for a lamination type, and the role of a cement base composite material is important. In this research, we developed a cementitious base binder applicable as a 3D printing exterior materials, confirmed high temperature strength characteristics for application as an exterior materials of buildings and confirmed its possibility.
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The exterior finish not only has a relationship to the functionality of building, but also the spatial aesthetics and visual perception. Common exterior finishes are wood, stone or acrylic based and etc. However, these finishes have different attributes which can alter the quality of the architecture, such as durability, moisture and fire resistance. To make up for the short-comings of these materials, we have used iron based resources for optimization. However, iron materials are expensive, so they have limitations in general use. In this study, we have experimented with various forms of exterior finishes using cement, which is the most efficient and widely used building material with several economic advantages. We experimented with different materials to use as the formwork for the gloss of the cement matrix. As a result, the gloss show that order of urethane, steel, and wood material.
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In this study, FT-IR analysis was performed by exposing cement paste to high temperature in order to characterize the change of hydration behavior of concrete structure damaged by fire accident. As the holding time increased, the Al-O vibration region increased due to the increase of Si-O symmetric Ca2(SiO4) and Brownilerite, and the OH stretching region tended to increase due to thermal decomposition of Ca(OH)2.
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In the labor-intensive construction site, potential threats of the musculoskeletal diseases mainly caused by various repetitive physical tasks, vulnerable environment, and the aging of the labor worker exist. However, quantitative measuring method of construction labor worker's work posture has not been improved yet. This study proposed musculoskeletal measuring method by using wearable motion recognition sensor for quantitative evaluation and analysis of working posture of construction workers. This method is expected to be used as a basic data for posture analysis and prevention construction safety accidents, as well as physical workload and labor productivity analysis by labor work type.
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This study aims to recognize damage indicators of typhoon and to develop damage function's indicators, using information derived from the actual loss of typhoon Maemi. As typhoons engender significant financial damage all over the world, governments and insurance companies, local or global, develop hurricane risk assessment models and use it in quantifying, avoiding, mitigating, or transferring the risks. For the reason, it is crucial to understand the importance of the risk assessment model for typhoons, and the importance of reflecting local vulnerabilities for more advanced evaluation. Although much previous research on the economic losses associated with natural disasters has identified the risk indicators that are indispensable, more comprehensive research addressing the relationship between vulnerability and economic loss are still called for. Hence this study utilizes and analyzes the actual loss record of the typhoon Maemi provided by insurance companies to fill such gaps. In this study, natural disaster indicators and basic building information indicators are used in order to generate the vulnerability functions; and the results and indicators suggest a practical approach to create the vulnerability functions for insurance companies and administrative tasks, while reflecting the financial loss and local vulnerability of the actual buildings.
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The cost of procurement in construction projects varies depending on the type of project, but the proportion of the cost component is very large. Therefore, efficient procurement system operation affects the success of the project. However, difficulties arise in procurement management due to problems such as availability of data due to limited information, inaccurate scheduling and integration of costs. Therefore, the purpose of this study is to develop a procurement management system to help efficient communication decision by combining Big Data which can analyze a lot of information and Block Chain technology which can secure information and record reliability to satisfy the above requirements. The results of this study are used to develop a system to develop academically improved procurement management system and practically to develop a system to secure business competitiveness and to facilitate rapid communication among project participants.
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In this research, we determine the proper number of entrances in the evacuation facilities for civil and military personnel. The current standards on the emergency evacuation facility only sets the number of possible evacuees and the according architectural floor area since the evacuation have been completed. However, other than static standards such as the floor area, there is needs to consider the dynamic standards along with allowable evacuation time such as the number of entrance, staircases and so on. Therefore, we need to consider the number of entrances and their location in order to account for the allowed evacuation time of particular number of people in a set area. The outcome could be contributed to the standards which should contain the dynamic conditions associated with evacuation.
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In the Public Notice No. 2019-15 of the Ministry of Employment and Labor, the safety net and regulations on them have been deleted. The performance criterion of the debris net, which also functions as a horizontal safety net in the regulations on the criteria of occupational safety and health, is unclear. When installing a debris net that also functions as a horizontal safety net, a net that meets the performance criteria of KS F 8082 must be installed in accordance with KOSHA C-31-2017. The Korean Standard Specification for Construction Works, which specifies debris net and horizontal safety net, should be revised as soon as possible.
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As information and construction technology increases, the demand for sophisticated geometric design grows. Design of buildings is becoming more larger, higher, and complicated every day, requiring much new construction technology to bring the design into reality. Nonetheless, the speed of construction technology development is not as rapid. This study concerns the difficulties of realization of sophisticated geometric design. It aims to suggest using BIM and precision survey equipment during the construction stage of the project is a way to resolve. The study will list how to use BIM as an engineering platform incorporating a photo scanner, a scanner drone, and a 3D scanner in the construction stage of projects, how these progressive projects were able to benefit from the high-construction technology.
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To overcome the limitation in relation to thermal insulator's selection and installation method that is suitable for exterior insulation and waterproof construction methods, a production basis of thermal insulators of which manufacturing knowhow is held by companies was ensured and future-oriented construction methods to adopt new materials were applied. Performance verification was conducted through performance and mock-up tests of thermal transmittance on the cross sections where the flexible insulators were applied based on the improved prototype and performance data were obtained. To overcome the biggest drawbacks (walking feeling and damage etc.) in the exterior insulation and waterproof construction method, inserting a protective layer between thermal insulator and water-proof layer was proposed, and polypropylene corrugated cardboards.
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In this study, we considered the influence on segregation resistance at the time of substitution of FA and BS, which are substance admixtures of high fluidity concrete. According to the research results, EIS, which is an index of segregation in high fluidity concrete replacement, showed a low value, and the composition also showed a higher value than OPC. Therefore, it is confirmed that the resistance to segregation at the time of admixture replacement of high fluidity concrete is improved.
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As part of the recent low-energy policy, insulation standards for buildings are increasing every year. In addition, the conventional styrofoam heat insulation material has a problem in that the thickness of the heat insulation material to achieve the standard heat transmission rate is rapidly increased. Although the risk of spreading the structure vulnerable to fire due to insufficient spacing between buildings due to thickened insulation is increasing, the high cost of high efficiency insulation is difficult to solve. On the other hand, it is known that the method to be used as a formwork using insulation is excellent in cost reduction effect by reducing the amount of formwork used and simplifying the subsequent insulation work. The purpose of this study is to evaluate the strength characteristics of multi - layered insulation materials with appropriate strength by reducing the thickness of the insulation by appropriately combining high performance phenolic foam insulation and styrofoam insulation.
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This study introduces the production and construction of building interior and exterior materials using UHPC for premix type room temperature curing developed through advance research and development.
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In contemporary residential culture, apartment houses can form individual independent residential areas within narrow territory. By using various building materials compared to the past, apartment house is recognized as an aesthetic space by modern people. However, as the number of cases of tile defects in apartment complexes has surged recently, aesthetic factors and quality of life have been reduced, and hundreds of millions of defects have been charged to builders every year. The tile defects in the apartment complexes of 90 domestic complexes are cracked, lifted, damaged, and dropped off. Most of the tile defects are caused by poor construction, but the defect occurrence rate due to thermal stress mechanism is high. Therefore, this paper investigates the case of tile defects in apartment house and identifies the defects and examines the problems that should be improved to reduce the defects of tiles in the building interior.
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Long-life housing should be durable enough to maintain structural safety even after long-term use by applying a durable structural system. Also, the residence space can be repaired according to the life cycle of the resident, and the space can be easily changed. The purpose of this study is to propose a plan which can increase the variability of unit space of long - lived houses in terms of architectural planning. We propose a new plan that can embody flexibility and ease of repair through the design of long life.
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Recently, major public owner and general contractors in Korea are actively preparing and improving BIM manuals and guidelines to effectively apply BIM technology in construction projects. These guideline has a purpose to define the scope of the applying BIM technology to each construction phase and to explain the minimum technology guidance required for the initial stage. In situations where BIM data are to be submitted within a limited time and cost at the design stage, a BIM data preparing process should be carried out in advance to meet the BIM interoperability between the pre and post of construction precess. In this research, we propose the scope of the BIM guidelines to meet and to be considered for the BIM based review of constructability and economic evaluation of Apartment.
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This study length variation test, shock test were conducted to evaluate the performance of synthetic resin form. Results of both thermal length variation test and shock test satisfied the KS standards. for length variation test, the result of the horizontal and vertical valuse were -0.1% in average.
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This study is a mock-up experiment prior to field application of insulated gang form. In order to investigate concrete Heating cost in winter, pre-comparison was made before application.
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Because of the congestion problems, the high-strength reinforcements are expected to be used in nuclear power plant structures in the near future. According to ACI 349-13, lap splices of high-strength(550MPa) bars can be used but it is expected that lap splice length of reinforcement will be increased significantly. The increased lap splice length will be lead to increase in construction cost & period and to problems of other bar congestions. Therefore, this study will analyze the economic feasibility on mechanical splice of high-strength reinforcement used nuclear power plant structures instead of lap splice.
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Reinforcing bars are an important material for tensile strength of structures. For this reason, the inspection of the reinforcing bars confirming the layout and omission is very important for the safety of the structures. However, the current method of inspecting of the reinforcing bars through photographs of specific areas is difficult to identify condition all reinforcing bars. And It is also difficult to confirm after completion of a building. Therefore, reinforcing bar inspection using 3D scanner is required for automation of rebar inspection and database construction. For this purpose, this study test application of automated inspection method for rebar inspection using 3D scanner and discuss the effect of this method.
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Reinforced concrete construction is one of the labor intensive construction projects and its productivity is very low. It is necessary to increase the productivity of rebar construction for improving the productivity of construction work. Therefore, in this study, the rebar drawings of apartment buildings are analyzed to prefabricate wall rebar unit shaped mesh in the factory and installing it on site. If the proposed wall rebar unit is applied to apartment construction working time of wall rebar can be reduced by 50% or more.
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The aim of the research is analyzing the performance of the concrete IoT management system invented with similar technique from 'G' company to certify the performance of CIMS. As a results, the compressive strength assessing performance was compared. Since both systems assess concrete compressive strength with maturity method based on measured concrete temperature, both systems measured concrete temperature similarly, and maturity was calculated similarly. Therefore, the assumed compressive strength values were similar for both systems. Therefore, through the test, compressive strength assessing performance of CIMS was considered as a similar level of the 'G' company's system. Furthermore, it is considered that the CIMS has an additional advantage of reusability, adding capability of additional sensor, and wider range of Bluetooth communication.
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Curtain wall is constructed in various forms and designs by forming the exterior walls of a building, and refers to non-bearing walls that divide the exterior and interior spaces of a building. Curtain walls require not only wind pressure, but also waterproof, insulation, insulation, and durability, as well as the effects of recent frequent earthquakes. Studies on the sleeve used to connect the vertical member mullions in the process of high-rise curtain walls are insufficient. In this study, sleeves connecting curtain wall mullions were developed to absorb external displacement, and the purpose of this study was to evaluate economic feasibility through comparison with existing construction methods.
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Curtain wall means a non-bearing wall that forms the outer walls of a building to divide the exterior and interior space. The increased use of curtain walls is diverse, including structural safety, watertightness, and wind pressure. As the government's energy conservation policy and the aim of zero-energy houses, the importance of heat reduction is also greatly increased. So, the study of monotony is constantly being conducted. Thus, in this study, insulation performance was analyzed through simulation according to the shape of curtain wall and the shape of insulation inside, and the purpose of this study was to provide basic data on the application of insulation criteria by energy saving design of buildings.
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This study examined the effect of foam volume ratio and curing temperature the air dry density and compressive strength of lightweight concrete using bottom ash. Test results showed that the lightweight concrete possessed the compressive strength of 3.4~22.7 MPa at the air dry density of 1,041~1,583 kg/m3.
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The EMP slip rate was compared with the general concrete using the electric arc furnace slag as an aggregate. Experimental results show that the shielding rate of concrete specimens using electric arc furnace slag increases. It is considered that the shielding rate is increased due to the high Fe content in the components of the electric arc furnace slag aggregate.
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In this study, application of ultra high performance concrete(UHPC) with pre-mix binder were presented on civil, architectural and special field. The UHPC can be applied to a variety of site due to its excellent flowability, mechanical properties, impact resistance and fire resistance. It is necessary to apply the pre-mix binder to take into account the productivity and performance improvements of the UHPC.
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In this study, the spalling and ultrasonic pulse transmission time of concrete were investigated according to compressive strength during heating. As a result, the higher the compressive strength of the concrete, the more the explosion occurs, which affects the cross-sectional loss and the spalling fragment size. Also, ultrasonic pulse transmission time was found to be strongly influenced by the section loss of concrete.
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Recently, efforts are made to apply 200MPa levels of ultra-high strength concrete to structures exceeding 40MPa.. Ultra-high strength concrete has been steadily researched in Korea as well as abroad, and now it is equipped with 200MPa ultra-high strength concrete mixing technology. Because ultra-high strength concrete has a higher range of compressive strength than ordinary concrete, it is difficult to accurately measure the compressive strength of UHPC concrete with existing compressive strength measuring equipment and can be less reliable. In this study, the compressive strength of the SC80 was measured according to the test method to compare the compressive strength of the SC80 by applying various methods of measurement of compressive strength. The compressive strength test method measured the compressive strength according to the size of the specimen, the grinding method, and the capacity of the UTM equipment.
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The purpose of this study was to investigate the possibility as mineral admixture of agriculture by-product. XRD and XRF analysis were performed on rice straw ashes at various combustion temperatures to identify chemical compositions. Also to evaluate properties of pozzolanic reaction, pH change method was tested.
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In this study, in order to find new uses for CBS dust, the chemical components of CBS dust were analyzed and effectively proposed a method. Chemical analysis shows that CBS dust contains a large amount of alkali in addition to chloride therefore, if CBS dust is used for secondary concrete products that use high amounts of mixed materials without rebars, it will be found that it can be used effectively for enhancing strength by active alkali.
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In this study, the optimization of mixing proportion of press-forming board with blast furnace slag, pearlite and bottom ash was investigated using the response surface methodology. Ten Mixing proportions of specimens were designed by the response surface design, and then flexural failure load, moisture content and water absorption of specimens were measured. As a result of the reaction surface analysis based on the experimental results, it was possible to derive the optimal mixing proportion with the satisfaction of 93%.
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Korea has defined fine dust as a social disaster as the problem of fine dust and air pollution becomes serious. Fine dust is classified as class one carcinogens because it is harmful to human body. When fine dusts enter the human body, they cause bronchial and skin diseases such as respiratory allergies, irritable pneumonia, asthma and atopy. As the air pollution becomes serious, the government is demanding measures to reduce fine dust. The polluted air in the outdoor is introduced into the room, thereby increasing the pollution degree of the indoor air quality. In this study, an adsorption type matrix for the improvement of indoor air quality was produced. Magnesium oxide and magnesium chloride were used as binders and diatomaceous earth was used as a adsorption material.
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In modern times, due to the centralized urban structure, the interval between buildings is narrow and the increase of the heat island phenomenon due to the accumulation of the structure is becoming a social problem. In order to solve these problems, various materials for reducing the surface temperature of buildings are under study. Particularly, in the case of a wall part which is a part directly affected by the outside air of the building, it is a main structural part for determining the room temperature. The purpose of this study was to develop a material that can improve the thermal environment performance of the building by evaluating the temperature control performance of the exterior finishing material using the heat reflecting material as a method for controlling the temperature of the outer wall finishing material.
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In this study, the characteristics of single-component and other sealant were analyzed to provide repair methods and effective utilization of sealant due to crack generation. Humidity studies have shown that acrylic silicone is effective in many areas of fluidity and temperature change, and that polysulfide-silicon is most effective in resistance to linear expansion coefficient and external pressure. Therefore, the difference between drying shrinkage and thermal expansion coefficient between various building materials and sealant, as well as the use of sealant, is analyzed, and construction methods derived accordingly, and prevention of defects are considered to be part of the construction project.
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In complex waterproofing method, the stability of the joint is an important factor. The joints should not be broken for repeated movements and tensile forces. Therefore, we tried to confirm the stability of joints in newly developed joints and general joints. Repeated fatigue resistance performance tests and joint tensile strength tests were carried out on four types of joints. The fatigue resistance performance test showed no abnormality in all four types. It was confirmed that the newly developed top-down joint has higher stiffness than existing joints.
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The purpose of this study is to design the basic mix proportions of antiwashout underwater polymer cement mortar as a repair material. The antiwashout underwater polymer cement mortars are prepared with various mix proportions using three type polymer dispersions without or with antifoamer. From the test results, the whole antiwashout underwater polymer cement mortars can be cast underwater without segregation like plain mortar. It is apparent that the flexural strength of antiwashout underwater SBR cement mortars with antifoamer at polymer- cement ratios of 5% and 10% is higher than that of plain mortar irregardless of a little low compressive strength.
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The temperature and relative humidity in concrete change with the passage of time depending on factors such as compressive strength. They are also different depending upon internal depth of concrete. In this study, we have measured the change of the temperature and relative humidity in the concrete for two years to act as the parameters to evaluate the concrete durability and effective maintenance.
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The aim of the research is evaluating the feasibility of inspection for early age frozen damage and for expansion of concrete under the various time periods of -20℃ temperature condition. When the concrete samples were exposed for 12 hours and 24 hours, the frozen depth of the concrete were 10 and 60 mm, respectively, under the wet conditions. From the experiment results of temperature and expansion, only surface area suffered frozen damage for 12 hours exposing conditions while entire area suffered frozen damage for 24 hours exposing conditions.
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The purpose of the research is assessing the possibility of strength recovery for mortar added with accidently high amount of fly ash. For compressive strength at 28 day, the sample painted with sodium hydroxide showed higher compressive strength than the sample painted with calcium hydroxide. Regarding the curing conditions, the curing temperature 65℃ provided better conditions than the curing temperature 20℃ in aspect of solution penetration depth and reactivity of fly ash. In the case of drying after saturation, the case painted with sodium hydroxid 65℃ showed the clearest engrossing mark.
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The high performace water reducing agent with three-hours-fluidity-retention performance is developed for the purpose of entering into the global market belonging to extreme environment such as Southeast Asia and the Middle East. In this study, the fresh and mechanical properties of the high strength concrete with three-hours-fluidity-retention performance are evaluated by making mock-up members in Vietnam.
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Recently, exposed concrete designs have been placed everywhere due to increased interest in indoor residential environments. In addition, in order to overcome the disadvantages of litracon, which was developed by mixing optical fiber, LEFC(Light Emotion Friendly Concrete) was developed in Korea, which improved unit price and constructivity by inserting hard acrylic rods. LEFC, using foaming agent and lightweight aggregate for light weighting, has disadvantages that decrease mechanical properties, and thus improved mechanical properties by using ultra-high performance concrete. Also, due to the characteristics of UHPC materials, it showed excellent self-consolidating performance. Considering these characteristics, a LEFC mold with pattern design was developed. The LEFC blocks were built so that pattern shapes could be seen and these were applied on-site to Sewoon plaza, located in Seoul.
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This study investigated the fluidity and compressive strength properties of blast furnace slag based non-cement paste containing ferronickel slag powder to evaluate the possibility of use in for cement replacement materials. As a result, the fluidity of non-cement paste showed a higher flow as the mixing ratio of ferronickel slag powder increased. The compressive strengths similar to those of the non-cement paste using only blast furnace slag powder were obtained when 5 and 10% of ferronickel slag powder were used.
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In this study, compressive strength was measured to evaluate the initial strength of cement mortar substituted with coal gasification slag containing desulfurized gypsum, and the reactivity of desulfurized gypsum was confirmed. In order to improve the reactivity, 2% gypsum mixed type and gypsum unfedged type specimens were fabricated and the influence of desulfurization gypsum on compressive strength of coal gasification slag and blast furnace slag fine powder replacement cement mortar was compared and confirmed. As a result of the experiment, it was confirmed that the initial compressive strength of the specimen containing the desulfurized gypsum was improved at the initial stage.
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Current international concerns are the energy crisis due to climate change and depletion of fossil fuels due to global warming. Korea has a very high dependency on energy imports 93%. In Korea, 63% of the country is forested, and a power plant using wood biomass is being built in Korea. Biomass fly ash, a by-product of biomass energy generation, is now being discarded. There is little research to utilize discarded biomass fly ash. Therefore, this study aims to solve the environmental problems, develop new mixed materials, improve the quality and utilize the biomass fly ash, which is a by-product of the industrial waste. As a result of the experiment, the flowability decreased as the replacement ratio of biomass fly ash increased. As the replacement ratio of biomass fly ash decreased, the amount of air content.
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It is possible to realize the concept of long-life housing by utilizing the wall piping infill system. However, when using the wall piping infill system, there is no detailed standard in Korea. Problems may occur in actual use. In this study, we use the results obtained from the performance test method as a basic data. Since the load resistance test of the toilet is not available in Korea, GB 6952 (Sanitary wares) of China is applied. According to the experiment of load resistance of the toilet in this study, the strain recovery ability was good. However, it is not possible to exclude the possibility of permanent deformation of the toilet seat due to long - term repeated loading. Therefore, it is necessary to consider the stiffness enhancement of the wall (steel frame) to the fixing part when installing the toilet in the wall pipe infill system.
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Oriented strand board(O.S.B) is used in many areas, such as interior and interior finishes of wooden houses, but no cases and studies have been used as flooring materials for flooring boards. In this study, we will examine the quality and performance of the aromatic strands board, which we believe can be substituted for the plywood, and analyze its suitability as a floorboard.
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Recently, due to abnormal climate phenomena caused by greenhouse gas, flood damage such as local torrential rain has been emerging in Korea. Accordingly, there is a growing need for porous blocks capable of permeability in concrete, but there are limitations in commercialization due to problems such as high unit weight and flexural strength development limitations. This study investigates the unit weight and strength properties of porous blocks using bottom ash as an alternative to aggregate as part of a study to improve the light weight of porous blocks.
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In this study, to overcome the limitation of material application as the surface layer of bridge decks (asphalt concrete, concrete), a newly developed waterproof sheet is proposed to be usable for both asphalt concrete and concrete. Subsequent tensile bond strength was tested, and the test results showed that the tensile bond strengths were similar to depending on the type of the surface layer material for bridge decks, confirming the applicability of the proposed material.
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The purpose of this study is to provide the basic data of government policy by evaluating the capacity of construction companies by country. As a result, Korea ranked 13th in construction competitiveness, 20th in design competitiveness, and 7th in price competitiveness among the 20 countries to be compared. As a result of evaluating the competitiveness of construction companies by country, Korea ranked 15th overall.
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Many attention have been paid to the innovative technologies aiming at the paradigm shift such as the modular housing, pre-fabrication method, or long-life housing. Despite the government's efforts to diffuse the long-life housing, few case gained the high grades by applying various technologies required in the Long-life Housing Certification System. The concerns of cost increase and low profit are the main reason why most of the construction firms avoid the adoption of long-life housing. In this study, the variations of construction costs were analyzed according to the grades in the Long-life Housing Certification System. The results of this study will help the decision makers find the optimal solution in employing the long-life housing technologies during planning.
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Virtual reality technology can be defined as human-computer interface that makes virtual place of specific environments or situation is an interactive computer-generated experience taking place within a simulated environment. In order to combine virtual reality technology of domestic nuclear power industry, the R&D Project has been developing a virtual/augment reality system for nuclear power plant from April 2018 to March 2021. To effectively apply virtual reality technology of domestic nuclear industry, it is necessary to build virtual space similar to real environment. Therefore, This study is analysed 3d model status for nuclear power plant during the life-cycle, and suggested a method to build 3D cad model close to real environment.
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The basic type construction cost which is the base of the building cost estimation is being adjusted according to the price changes by utilizing the apartment construction cost index in order to flexibly operate it. In this study, we analyzed the change trends and characteristics of the housing cost index for the basic type building cost model project operated from September, 2012 to March, 2018. As a result, the increase in material costs is slight while the share of the labor cost increased in the construction cost due to the rise of labor unit price, leading to a perceived increase in sensitivity of labor costs. We should be careful to keep the sensitivity of the material cost and the labor cost to an appropriate level so that the index may not be distorted.
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This study performs analyzing a status of labor cost policy of public construction project and labor management information system in Korea for improving of labor cost survey in the construction market. The outcome of this study will be helpful to build a labor cost information system included the information of man-hour, regular pay and benefit, total wage. And if these result is integrated with the information of worker's career, qualification, skill level, it is confidently expected that the survey of labor cost is reliable.
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The nuclear power plant construction project is large-scale, has various stakeholders and computer system, and is produced and managed a large amount of information. The domestic nuclear power plant construction project has accumulated data based on many years of experience in the system. It has the competitiveness to suggeest alternatives that meet the requirement of the client in the overseas nuclear power plant project. Earned value management, which integrates schedule and cost, is possible to risk management. It was developed the earned value management system considering the the actual data properties and types of the preceding nuclear power plant construction projects. It will be able to increase the nuclaer power plant export competieiveness. Therefore, it was palned to carry out future stuies so that it be able to complement the measure to integrate cost and schedule in consideration of actual data(quantity of activity, etc.).
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The plater work in the standard of estimate presents a variety of construction types. However, there is a part that does not fit the change of specification standards and on-site construction status, and it was revised in 2019's standard of estimate. In this study, we analyzed in detail the factors affecting the changes in estimating standards in the plater work. There were changes in the specification standards previously presented as primary coat, secondary coat, and formal coat as well as changes in on-site construction status such as thickness according to the number of plastering. Therefore, it is analyzed that the estimating standards can be classified by the number of finishes according to the site conditions by reflecting the analysis of the specification standards and site application status, and suggesting the finishing standards according to the number of plastering.
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In the stacking and pitching items of the stone masonry and demolition process presented by 2018's standard of estimate, 7 estimating standards are presented according to the depth of masonry stone, and it is presented that the quantity per unit increases as the depth of masonry stone grows. As a result of analyzing the application status in the site, it is shown that 2 or 3 stones are mainly used according to the stone sizes regardless of the depth of masonry stone, and that as the size of the stone becomes larger, the quantity per unit decreases due to the size per square meter(㎡). Also, in most of sites, machine construction is mainly carried out by excavators with clampers attached to them. Therefore, in the 2019's application standard of estimate, it is analyzed that the size is simplified down to 3 sizes reflecting the site application status and that it is revised as a standard reflecting the result that as the stone size becomes bigger, the productivity increases.
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Building Information Modeling (BIM) and modular construction are regarded as important technologies that address several issues faced by the construction industry. However, the application guidelines for BIM in current modular construction projects are insufficient. This paper presents the preliminary work on the analysis of BIM utilization in a modular construction project; a five-point likert scale questionnaire was conducted to assess the necessity of BIM applications by the Necessity Index(NI) of nine categories(U1~U9) across two construction phases (onsite and offsite). The survey results indicate that applications for BIM based quantity takeoff for offsite phase(U4) as well as BIM modeling for module joint details(U8) were deemed to be the most necessary in each phase. The results of this study can be used as detailed guidelines for the integration of BIM in modular construction projects.
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In this study, it was intended to confirm the possibility of using the Durometer in estimating the setting time by comparing the Proctor penetration resistance with the Durometer type A of hardness in concrete substituting CBS Dust. With the hardness of Durometer type A, it is expected to be used conveniently in the field of practice as it is determined to be about 18 HD for the initial determination and 31 HD for the end measurement.
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Construction disasters have more distinctive characteristics than other industrial disasters. Since it is likely that construction disasters will spread to severe accidents, the accident mortality rate is very high compared to the disaster incidence rate. Therefore, the purpose of this study is to compare and analyze the operation status of construction risk assessment by domestic large and medium sized construction companies to prepare improvement direction of risk assessment system. The survey results for safety management experts of construction companies are as follows: Large companies have developed and utilized risk assessment systems in their respective companies, while small and medium construction companies have developed and evaluated risk factors through the Excel program. Rather than performing risk assessment tasks based on historical safety accident data, construction companies have limitations in developing risk factors and preparing solutions with suppliers for each major construction. Therefore, it is necessary to prepare a risk assessment system in the future by analyzing the types of safety accidents, such as the safety accident data of each company as well as the safety accident data.
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In recent years, road cutting work has been frequently performed for the repair of old road pavement and the development of underground space. However, the existing pavement cutting machine in Korea generates a lot of noise and dust. In this study, it was found out that the pavement cutting machine that cuts off noise and sucks cutting dust is used in overseas. Therefore, in this study, the concept of eco - friendly pavement cutter suitable for domestic situation is derived. The results will be used in prototype modeling and experimentation.
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Recently, a variety of window cleaning devices have been developed. There are, however, few cases of anticipated problems and countermeasures that may arise after these devices are installed. Therefore, in this study, the emergency condition was derived and the emergency scenario was derived for the rail-mounted cleaning device. Emergency scenarios and countermeasures derived from this study will be used for continuous improvement and supplementation of cleaning devices through prototyping and testing.
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This study was conducted to provide useful information to enable planned repair and cost planning during the operation and maintenance phase of aged multi-family housing. For this purpose, The concept of probabilistic maintenance cost analysis considering the risk factors of the aged multi-family housing is presented in the following six steps. 1. Risk factor investigation and analysis 2. Classification and deriving of maintenance cost 3. Investigation and deriving cost maintenance cost of old apartment house 4. Analysis of expert questionnaire 5. Analysis of Monte -Carlo simulation 6. Probabilistic maintenance cost Deriving the result. This study has limitations that need to be verified by applying actual data.
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In the nuclear industry, in order to keep pace with the 4th industrial revolution era, they are trying to improve the construction and maintenance ability by utilizing the technologies such as digital twin and VR/AR from the construction stage. However, the nuclear 3D CAD model, which is used as the base in the latest technology, is heavy due to a large number of facilities per unit space compared to other industrial companies, and it is difficult to directly incorporate the latest technology into the results of CAD programs for design purposes. In this study, in order to improve usability, we tried to lighten the 3D model. First, we analyze the existing nuclear power plant 3D model and draw out the problems and features. Secondly, we derived the factors to consider when we make the 3D CAD models lightweight.
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Lots of infrastructures have been newly constructed through the rapid economic growth of 1970's. Since the infrastructures has mostly deteriorated and this circumstance makes the need for maintenance and rehabilitation(M&R) of infrastructures to obtain the convenience and safety of users even more essential. Although markets for M&R project become larger, the construction standards for cost estimation of M&R work are insufficient. Thus, the purpose of this study is to examine the present state of standards for cost estimation of M&R works using case studies. Finally, this work could be utilized as the basis for the development of national standard for estimation of M&R work.
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Corrosion of rebars in reinforced concrete structures is a major factor that shortens the life of the structure. As corrosion progresses, the adhesion between the concrete tissues and the rebar decreases and the cracks in the concrete due to the expansion of the oxide intensify. Although it is necessary to measure corrosion behavior of rebars inside the concrete to measure degradation of structures due to rebar corrosion, no studies have been conducted to measure corrosion of rebars in In-situ state. In this study, corrosion of rebars in reinforced concrete specimens was attempted to be quantified using micro-computer tomography. Since corrosion of concrete takes several months per 10mm of cover, accelerated corrosion techniques were applied. Accelerated corrosion on the specimen was conducted by applying a 10 V magnetic field to the buried rebar and external electrodes with the specimen submerged in a 10% calcium chloride solution. The experiment found that within two weeks, more than 40% of rebar reduction occurred, and the cracks in the radial cracks occurred through the concrete structure, leading to the transfer of the oxide produced through the cracks to the surface of the specimen.
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Recently, the fire risk of architectural structures is increasing due to the super high - rise and super - size of the buildings. Therefore, the direction of fire safety design tends to change from the existing design to the performance - based design. In particular, domestic fire safety policies are divided into building law and fire fighting law. In case of fire fighting law, performance design is already carried out. Therefore, this study summarizes the prediction formula for fire characteristics among the structural fireproofing design field as shown in Fig. 1 according to this situation, and compares it with the standard method of each country in particular.
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Corrosion of rebar in RC structures, which results in premature deterioration of reinforced concrete structures, is a very serious problem. Most corrosion monitoring and sensing technologies require some type of wired or wireless connection between the sensor and monitoring electronics. This causes significant problems in their installation and long-term use. In this paper we describe a corrosion monitoring technology of rebar in reinforced concrete structures. Especially, it is emphasize that the development of sensors and monitoring system not only occurrence of rebar corrosion but also penetration of deterioration factor such like chloride ion and carbon dioxite etc..
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Corrosion of rebar embedded reinforced concrete is the main cause of collapse and degradation of reinforced concrete structure that many researches are recently focused on these works. Methods of evaluating rebar corrosion are divided into physical and electrochemical methods. However, the result of Conventional methods are less reliable due to effect of internal and external environments. In this study, rebar corrosion detection sensor for embedded rebar of RC structures is evaluated through immersion test in NaCl solustion for 160hours. From the results, Rebar corrosion was ongoing and corrosion products are produced on rebar surface. The voltage is decreased as amount of corrosion production increased.
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In this study, a sensor for detecting corrosion of rebar embedded in reinforced concrete structures was fabricated and its performance was verified. In order to monitor the open circuit potential(OCP) of the rebar embedded in reinforced concrete, a concrete embedded solid electrode was constructed as a sensor using MnO2. The OCP of the rebar could be observed using a sensor and a data logger. The decrease of the OCP to -510mV (vs.MnO2) or less was judged to be corrosion of the rebar. Since it is a solid-mediated sensor, it is more stable and durable than an electrode using an aqueous solution, and it is considered that the corrosion state of the rebar can be monitored for a long period of time.