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
2018.05a
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Recently, high-strength concrete used for shortening the construction time of high-rise building construction, Concrete pumping technology is emerging as the core technology of high-rise buildings. In this paper, we have started to study the use of electromagnetic field as a method to increase the efficiency of the lubricating layer between the inside of the pipe and concrete, which has been established as the most important factor determining the pumping performance. The pumping performance improvement effect of concrete strength was verified and basic research was carried out to utilize it as a method to increase the efficiency of pumping in field application. In the related work, the effect of the electromagnetic field was verified by conducting a mock-up performance evaluation (horizontal 300 m) of the pumping force by the concrete strength.
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Although the importance of the construction lift is increasing, no improvements are being made to its operating system. This study proposed an optimal call-response algorithm of the construction lift for high-rise building construction by using image sensing technology, height measuring sensor, and load cell. This algorithm makes turn-around decision of the construction lift by considering the information and the number of user. It occurs when the call comes from a floor where the construction lift already have passed. The purpose of this study is to reduce the total latency of the construction lift user. Furthermore, it is possible to prevent delay in construction duration by carrying out a priority operation of the construction lift for the critical workforce.
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In recent years, the fire risk in the aged housing facilities in high-rise building has been closing up due to the fire in the Grenfell Tower. In the case of these high-rise residential facilities, fire cases of residential facilities such as Uijeongbu Apartment Fire The fire hazard has been reexamined mainly. Especially, the fire of these residential facilities is very closely related to the window, so measures are needed. On the other hand, in Korea, there is almost no fire safety measures against these openings. Therefore, this study suggests improvement measures by comparison with advanced countries based on fire safety measures for domestic windows.
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In the building, the opening penetrates the wall and serves as a spreading channel for smoke and flame in case of fire. In Korea, more than 1,500 fire plume are generated annually, and the number has increased by about 30% over the past five years. Therefore, in the case of windows protecting the opening, fire protection performance is important to prevent the spread of fire. However, in Korea, the standard for window is not clear. In this study, fire tests (EN 13823) for windows were conducted in Korea, and then fire protection performance of windows was compared. As a result of the experiment, PVC windows showed a phenomenon that they could not withstand the temperature during the fire experiment, and AL windows showed a difference in the degree of cracking of the glass.
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The purpose of this study is to propose a prototype of an artificial reef primarily composed of space frames and precast concrete members, and also to investigate the structural performance of the reef. The results described in this research confirm that the proposed artificial reef has a structural capacity to withstand 300 kN.
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This study is to estimate the buckling characteristics of single-layer latticed dome with Span 300m according to junction's conditions of member.
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With the technological advancement of the construction industry, construction materials with future direction appeared. In Korea, LEFC(Light Emotion Friendly Concrete) has been developed and studied, which has improved labor productivity and economic efficiency over semi-transparent concrete by introducing transparent plastic rods into concrete matrix. However, there is a problem in that the bending performance is lowered according to the insertion of the rod and the bending performance is different according to the light transmission direction. In this study, the incorporation of PVA fibers in the direction of light transmission was increased and the change of flexural performance according to the interval of light transmission was examined.
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For this study, a test was conducted on the basic polymer property depending on the replacement amount of polymer. The result showed that the flow of slump was increased with the increase of polymer replacement amount and an amount of air entraining. In addition, with a decrease of unit W/B, an amount of bleeding was reduced, and the first and final time for 6% replacement amount was found to be the fastest. This implies that replacement of more than 6% may affect the hydration of cement.
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Experimental Study on the Heat Shielding Performance of Lightweight Foamed Concrete Using EPS beads.Foamed concrete is a porous concrete that is cured by mixing bubbles into cement slurry. It is lighter than ordinary concrete and is characterized by higher insulation. Lightweight foamed concerte is mainly used as a sandwich panel in Korea, and is also used as a refractory filler in fireproof safes. Studies on lightwight foamed concrete have been carried out on strength,density and thermal conductivity. However, it is confirmed that the research on the fire resistance performance is very limited. Based on this study, fire resistance of lightweight foamed concrete using expanded polystyrene beads is investigated.
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Most finishing materials are vulnerable to durability, humidity resistance and fire. And those products used formaldehyde to protect, during the manufacturing process. Also most finishing materials used adhesives to construction process indoor. All of these elements are major causes of releasing formaldehyde. In this study, concrete used by phytoncide was examined to remove the formaldehyde. As a result of the experiment, we found that compressive strength was increased and formaldehyde effectively removed by using mixture of cement matrix and phytoncide.
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In this study, the device was developed for evaluating the effect of pressure on chloride ion penetration of concrete. And chloride-ion penetration depth and water soluble chloride contents was evaluated concrete using ordinary portland cement and blast-furnace slag cement using developed device. As a result, chloride ion penetration of concrete was promoted according to the action of pressure and the exposure period. and the incorporation of blast-furnace slag was effective for chloride attack resistibility under pressure.
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Deterioration of reinforced concrete structures due to salt corrosion is a phenomenon that can be easily seen, and the main reason for deterioration is chloride ion. Therefore, researches are actively conducted to control chlorine ion penetration worldwide. The purpose of this study is to evaluate the chloride ion fixation capacity of Portland cement paste containing Hydrotalcite. For this purpose, cement paste containing 0%, 2.5%, and 5% of Hydrotalcite was sealed and cured for 28 days, and the cured cement paste was crushed. Chloride ion solution was prepared at a concentration of 0.5M using NaCl, and the powdered cement paste was reacted for a specific time in aqueous chloride ion solution. After the reaction, the concentration of the chloride ion aqueous solution was measured using a silver nitrate potentiometric titrator, and the reacted cement paste was analyzed using XRD and FT-IR.
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Recent impervious pavements on roads and sidewalks cause rainwater to not penetrate into the ground, deplete groundwater, or flood the rivers, causing urban flood damage. In order to solve these problems, the amount of installed pitcher block is increasing, but the existing pitcher block is made with cement base and causes many problems. In the cement permeable block, the efflorescene phenomenon occurs due to the acid component, and the pore of the permeable block is clogged and the permeability is lost. As a result, the service life of the pitcher block is shortened and the replacement period is shortened. The purpose of this study is to analyze the basic properties of polymer concrete by replacing cement with polymer in order to solve the problem of cement - based concrete permeable block.
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Currently, free-form building has been increased worldwide. However, as a finishing material of free-form building, the production of free-form concrete panels(FCPs) spends lots of cost and efforts since it is difficult to reuse the FCP formwork and lots of workers are needed to make free-form curve. In addition, the technology to produce the FCP economically and easily is insufficient. Therefore, the objective of this study is a basic study regarding production management for developing free-form concrete panels. To achieve the objective, the property of FCP and condition for effective production management and production process are analyzed. The results of this study can utilize to develop the algorithm for FCP production management.
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According to the nation's greenhouse gas emission statistics, greenhouse gas emissions have been stiffly increasing. Accordingly, the importance of CO2 reduction is more getting focused over the world. This trend makes the construction equipment be considered as a major target of reduction due to the large volume of emission. This study suggests the feasible methodology for estimating CO2 emission from construction equipment and for being easily applied on the job sites. The methodology is based on the collection from the segmented CO2 emission information of construction equipment. This study allows site personnels to estimate the total amount of CO2 and to take appropriate actions for reasching the environmental regulations.
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BIM(Building Information Modeling) in the architecture, VDC(Virtual Design and Construction) defined CIFE(Center for Integrated Facility Engineering) of Stanford university in USA, and Data-driven design definition issued by TECDOC-1284 of IAEA are doing data-level design generated by 3D CAD technology, integrating and managing related information based on the 3D model, and Using 3D models effectively during nuclear power plant life cycle. 3D model of domestic nuclear power industry is using interference review between design fields, 4D system linked 3D construction model and schedule activity, but the 3D model generated in the design phase is effectively not utilized during the construction, operation, decommissioning. therefore, This study is aimed to suggest 3D model LOD(Level of Detail) advancement method through the analysis of existing literature, 2D drawings, and 3D models throughout nuclear power plant lifecycle.
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The goal of site layout planning(SLP) is to maximize the productivity and efficiency of the construction by reducing travel distance and material handling cost and manpower. However, SLPs are static layout schemes, which cannot be reorganized during the construction process to correspond with errors, phase transition, changing working environments on the site. To solve this problem, researches on dynamic site layout planning(DSLP) are emerging. This preliminary study clarifies characteristics of temporary facility's variables to develop the vertical DSLP algorithm of high-rise building construction.
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Various methods that crash the project completion time have been studied. Line-of-Balance (LOB) is well accepted as a useful method that enables steady resource utilization without frequent hire-and-fire of resources for a project having repetitive units. Existing studies involved in LOB-CPM focuses on thesis such as resource leveling and optimization in construction scheduling community. However, crashing methods are not arrived at a full maturity in LOB scheduling, because no one handles steady resource utilization while keeping activity-relationships. This paper proposes a method that crashes project completion time by hybridizing concurrent engineering and LOB scheduling without using additional resources.
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In the past, safety management has been carried out mainly by constructors, but now, participants of all construction projects such as clients, designers, constructors, and construction managers are being changed to perform safety management together. Among them, the design safety review, which examines whether the client has secured the design safety at the design stage, has been implemented since May 19, 2016, but it has not been properly implemented. Therefore, this study analyzed perception level and problems of D.F.S in architecture design firms and suggested the solutions.
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The fire at the pilotis parking lot shows the fire propagation paths that are propagated to the ceiling materials and insulation materials and propagated through the external walls. In addition, there is a high risk of fire caused by vehicles with high combustion loads spreading throughout the parking lot. In particular, the omission of the ceiling materials at the parking lot in recent fire cases has contributed to the spread of the fire. In this study, the combustion performance of the ceiling materials between the insulation material and the vehicle is considered to prevent fire from spreading. Based on field research, the type of ceiling material used in the piloti structure showed that SMC ceiling materials have the highest percentage. Combustion performance test (KS F ISO 5660-1) was carried out on the SMC ceiling materials and the AL ceiling materials to review the fire safety of the ceiling finish based on the field investigation. The results of the test showed that the SMC ceiling materials has a THR 28.973[MJ/㎡] and peek HRR 273.93 [kW/㎡], while the AL ceiling material has a THR 0.584[MJ/㎡] and peek HRR 15.215[kW/㎡].
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The aim of the research is to suggest the compensating strength values depending on various managing periods of concrete based on the strength development model calculated with equivalent age method for OPC 100 % concrete. As a result, for 28 days of managing period, 6, and 3 MPa of compensating strength values were suggested when the temperatures were from 4 to 9℃, from 9 to 17℃, respectively. Additionally, for 42 days of managing period, 3MPa of compensating strength value was suggested when the temperature was from 4 to 10℃, and for 56 days of managing period, 3 MPa of compensating strength value was suggested when the temperature was from 4 to 5℃. Furthermore, for 28, 42, 56, and 91 days of managing periods, any compensating strength values were needed when the temperature were higher than 17, 10, 5, and 4℃, respectively.
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In this study, it evaluate the electromagnetic pulse shielding performance of amorphous metallic fiber reinforced cement composite with other steel fiber reinforced cement composite. Hooked-ended steel fiber, smooth steel fiber and amorphous metallic fiber were reinforced 2.0 vol.% in cement composites respectively. The electromagnetic pulse shielding performance was evaluated by MIL-STD-188-125-1. As a result, shielding performance of amorphous metallic fiber reinforced cement composite was higher than Hooked-ended and smooth steel fiber reinforced cement composites. In addition, the relationship between the electrical conductivity and the electromagnetic pulse shielding performance of the cement composite was confirmed.
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In this study, viscosity analysis of the lightweight foamed mortar was conducted to evaluate the foam stability. According to a series of experiment, void volume related with density of the mixture and viscosity of the mixture were infleunced by water-to-binder ratio and addition of viscosity modifying admixture (VMA). Especially, the stability of the foam inside the mortar was confirmed with adding VMA.
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Reinforced concrete is a building material that is generally used in modern society. Securing the performance of reinforced concrete is directly connected to the durability and longevity of the building. One of the major factors that deteriorate the durability of concrete is harmful ion. Recently, the quality and improvement method of reinforced concrete for penetration of harmful ion has been studied. In this study, the bead type ion exchange resin is substituted for 0%, 3%, and 6% of the fine aggregate volume in the mortar. The speciments underwent underwater curing and were checked for compressive strengths of 3 days and 28 days. From the results of compressive strength, it can be seen that the higher the substitution ratio of the ion exchange resin, the lower the early strength and long-term strength development, especially the early strength development.
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This study is a fundamental consideration for using CGS from the IGCC as a fine aggregate for concrete. For the review, the physical properties and hazardous materials content of KS F 2527 were considered. The results showed that KS F 2527 standard was generally satisfied, making it possible to confirm the possibility that it is a fine metal considering its physical properties and hazardous materials content characteristics.
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In this study, firing experiments were carried out to confirm the foamability of the expansive shale collected from the local area. When expansive shales are subjected to high temperature heat, gas is generated inside and voids are formed. Due to this phenomenon, shale is used as a raw material for lightweight aggregate. Experiments were carried out with different plastic temperature and residence time to find the appropriate plastic temperature for this expansive shale. As a result, the higher the plastic temperature, the more the surface viscosity increased and the gas generated inside were retained. Resulting in a number of internal voids. However, even if the plastic temperature or the medium temperature is high, it is confirmed that sufficient gas is not generated when the residence time is shortened.
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Finishing materials are very important to restrain fire spread from a compartment to another in a fire situation. Therefore, the evaluation of combustible properties for the combustible material is essential to apply finishing materials into a generic buillding or s special occupancy structure. In this study, the testing methods for evaluation of combustible performance of finishing materials of domestic were surveyed in order to prepare the guideline of application of finishing materials in nulear power plant.
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Oyster shell is produce by shucking process in oyster farming in southern coast of Korea. In average, about 6.7kg of oyster shell is produced as an industrial waste for 1kg of oyster flesh, and even only in last year, it is estimated that about 150,000 ton of oyster shell is produced. Oyster shell is light weighted and the strength characteristic of it is similar to send. So we produced mortar test piece using grounded oyster shell according to aggregate and reviewed strength characteristic. Therefore, in this study, the strength characteristics of the test specimen are evaluated by artificially altering fineness modulus and curing method by processing oyster shells.
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Large-scale construction projects require various license and technologies for the manufacturing and handling processes. Also, the whole life cycle business process management determines the success of the project. Then, the efficiency of the business conducted by stakeholders and their possessed technology should be enhanced in order to strengthen their competitive power. For this reason, many experts pointed out to focus on the improvement of the life cycle process and efficient management. Since it is very important to keep up-to-date data and utilize it for work during the long-term project to reflect changes in the large-scale project, the most important part of the project management in project is information change management. Therefore, the objective of this study is applying configuration management(CM) technique in order to managing change data generated for planning in early phase. The result of this research will certainly assist the large-scale project managers in the development of information change management system.
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The construction drawing is a collection of knowledge that has accumulated knowledge and experience of designers and is highly valuable for recycling in the future. BIM is a process and technology that acquires and manages the information needed for the whole life cycle of a building. In order to recycle digitalized 2D drawings in BIM Tool, it is required to use 3D information based on the drawing information to save and reuse them, but there is little research on related methods or system development. In this study, 3D elements are created based on 2D drawing information, and libraries are constructed, and BIM Tool is used to improve the recyclability of drawing information.
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The labor cost on construction project of Korea is calculated based on the Wage Rate in Construction of Korea which is published by Construction Association of Korea. The Wage Rate in Construction of Korea does not have any variation on the wage following skill level of labor although it has 123 work categories. In addition, the classification on skill level and career of construction labor in Korea does not defined. Therefore, to establish the concept of the classification on skill level and career of construction labor, this study aim to compare the difference between Wage Rate in Construction of Korea with Award system which present grade on skilled labor.
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The accuracy of contingency estimation plays an important role for dealing with the uncertainty of the financial success of construction project. Its' estimation may be used for various purposes such as schedule control, emergency resolve, and quality expense, etc. This paper presents a contingency estimation method which is schedule control specific. The method 1) implements stochastic EVMS, 2) detects a specific timing for schedule compression, 3) identifies an optimal strategy for shortening planned schedule, 4) finds a probability density function (PDF) of project cost overrun, and 5) estimates the optimal contingency cost based on the level of confidence. The method facilitates expeditious decisions involved in project budgeting. The validity of the method is confirmed by performing test case.
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VE, rather than just cost reduction tool, have established as a value enhancement tool of the construction industry. Value improvement types of VE proposal can show the effect of VE activities, also acts as an important element in which the owner adopts a proposal and confirms the results of the VE activities. However, problems in the process of quantification for VE proposal and ambiguous standards in classification of value improvement types is need to be supplemented. Accordingly, This study suggests the plan for establishing of numerical range criteria for classification of value improvement types of VE proposal. Implementing this plan will be able to improve the reliability and availability for VE activities.
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Under industry 4.0, Internet of Things (IoT) is advancing a new breed of smart manufacturing environment. However IoT has not been widely applied in construction industry compared with manufacturing environment. IoT enables operational systems that deliver more accurate and useful information for managing construction accidents. IoT enables operational systems that deliver more accurate and useful information for managing construction accidents. In order to apply well IoT for construction safety management, as a preliminary study, this paper presents e safety accident prevention IoT Cone system through dangerous area setting in construction site.
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The facilities of domestic elderly people are getting higher in the facility due to the rapid increase of the elderly population. Elderly people ability to evacuate the facility such as cognition and walking ability is very low. Therefore, it is necessary to secure the safety of evacuation in case of fire, but the evacuation safety measures in case of domestic fire accidents are insufficient. This study is to identify the problems of the safety of evacuation through the fire case analysis and to propose the measures against it.
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In this paper, we investigate the characteristics of wet soil concrete according to the addition ratio of liquefaction red mud addition rate by liquefying red mud. as a result, the compressive strength decreased and the water absorption ratio increased as the liquefaction red mud addition rate increased.
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Development of 3D Printing Cement Based Composite Materials Applying for Exterior Finishing Material3D 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 bonding material is important. In this research, we developed a cementitious base binder applicable as a 3D printing exterior materials, confirmed density and strength characteristics for application as an exterior materials, a flame retardancy test for improving the fire resistance of buildings and confirmed its possibility.
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In the case where the building's rooftop was laid without any foundation, the combined deterioration, such as the repetition of shrinkage and expansion caused by temperature changes, caused further cost generation and damage. To prevent this, the concrete mixing design and construction process shall be established to resist combined deterioration.
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The change in the degree of powder in cement is very important because it plays a major role in the reaction in the concrete. In this study, we intend to apply the principle of early estimation of concrete strength using the non-middling method previously conducted to the quality evaluation of cement powder. In other words, it is proposed to analyze the potential of Hydrometer density values and the data of temperature variation in the trust solution to propose a method of acceptance inspection. According to the experimental results, the quick evaluation of the cement distributorship will be possible if the resulting regression results are used : y = 161867.4 x1 + 117.953 x2 - 165437 (R = 0.9158).
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The strength of cement mortar is one of the most important factors in design and construction. Strength can vary widely depending on factors such as water cement ratio, aggregate and materials and curing. In the study, it was found that the standardized method of making the cement mrtar was different from the standard method of preparing the cement mortar by the different process of the cement mortar. I wanted to know the difference. Experiments were carried out to investigate the differences in strength, physical properies and performance depending on the points when the sample were made long in vertical form.
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A glassy thin film was formed on the surface of the blast furnace slag. When blast furnace slag is used as an admixture of concrete, addition of alkali activators were required. However, alkali activators are not only dangerous as chemical products, but they are also difficult to use as expensive materials. Therefore, it is necessary to study the way of removal of the glassy thin film of blast furnace slag without the risk and cost increase. In this study, to solve this problem, experiment was carried out to improve the hydration reactivity by treatment the surface of blast furnace slag using arc discharge. Experimental results show that when the surface of the blast furnace slag was tratmented by arc discharge, the glassy thin film was destroyed. And the hydration reactivity was improved, the compressive strength was increased.
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This study investigated the compressive strength and drying shrinkage properties of mortar using ferronickel slag powder by the kinds of industrial by-product to estimate the applicability of ferronickel slag powder for cement replacement materials.
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Despite of its advantange on shortening framework period of a super-tall building, gangform is prone to high safety risk due to its heavy weight during operation. Thus, this study is conducted to investigate the applicability of a lightweight gangform made of engineering composite materials. Compared to the conventional gangform, the proposed gangform showed greater performance not only in reduction of safety accidents on-site, but also in constructability and environmental aspects. The results of this study are expected to be served as the basis for developing the lightweight gangform in future.
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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, it is permitted to use the high-strength(550MPa) hooked bars in design of development length, but there is no special equation for high-strength bars. In order to reflect the anchorage capacity and behavior properties of high-strength bars with large-diameter(43 & 57mm), it is necessary to develope the new development length equation for large-size and high-strength bars.
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There is a risk that the damage caused by frequent earthquakes can lead to the risk of personal injury due to cracks in buildings and collapse of major structures. Although the seismic design of the new building is designed to be reinforced, the existing structure is not exposed to the risk of earthquake. Therefore, it is aimed to develop the steel frame type CFT composite method which can easily reinforce the CFT structural system with excellent seismic performance against the old non - seismic structure.
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Recently, in addition to greening of roof and artificial soil, Rootproofing to prevent damage to the waterproof layer and structures by roots is recognized as an important task. Therefore, various related products and construction methods have been developed and applied in the field. However, in the case of synthetic polymer-based sheets most commonly used in domestic construction sites, Most are produced using 100% new materials that are not suitable for green trends such as resource conservation and environmental protection. Therefore, in this study, we developed TPO sheet using recycled material, which is a technology that can secure eco-friendliness by utilizing recycled resources. As a result of the evaluation of tensile performance of the TPO sheet according to the recycled material content, The tensile strength of the specimens with the recycled content of 50 ~ 70% was the highest, The elongation rate of the specimen with the recycled content of 30 ~ 40% was the best.
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Cracks are typical defects that occur in concrete structures. When cracks occur in the structure, durability reduction, concrete neutralization, and steel corrosion cause functional safety problems. In order to prevent such cracks, surface repair method is performed for cracks smaller than 0.3 mm and rechargeable method is performed for cracks larger than 0.3 mm. However, even if it is applied by the surface repair method at less than 0.3 mm, re-leakage cracks continue to occur. Recently, the Supreme Court ruled that the rechargeable method should be applied to cracks less than 0.3mm in order to reduce the occurrence of defects. However, it was considered that the repair fees were too high relative to the observed defect rate, resulting in a necessitation of modifying the existing construction analysis administration standards. This study analyzes the differences in the subjective views on the durability degradation with regards to surface repair methods in concrete structures.
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In this study, we applied the fiber sheet made by the stitch bonding method, which is a structure in which transverse yarns and double yarns are crossed by applying the principle of sewing knitting without the use of adhesive, The tensile strength of the reinforced concrete structure was investigated. As a result of the tensile strength test of each specimen, the specimen to which the fiber sheet produced by the stitch bonding method was applied exhibited the highest tensile strength among the three types of specimens, and the fiber sheet produced by the needle punching method exhibited the lowest strength. In addition, the stitch - bonded fiber sheet showed a difference of strength of 0.1N / mm for both length and double - sided strength difference.
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Preloading Strut applied during installation of the wall jack, but additionally serves to minimize the displacement of soil pressure acting upon dissolution due to the difficulty. In this study, we developed an index of support for the release of stress to facilitate the dismantling of the strut uninstall. The refractive support the axial force acting on the strut are supportable, is refracted at minimum load, disassembly should be easy. In order to find the optimal shape and structural stability of the refractive support We have performed the numerical analysis and performance test to determine the final model. We carried out model tests and UTM test in order to understand the refractive performance and durability of the refractive support for optimal model. Results of the test UTM is refracted all shot 5 times within a target hit number, it was found that there is no problem of the refractive performance. Further, the results of model experiments, it was found that to ensure sufficient durability more than the performance target value of the pin joint support structure.
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As the building becomes more sophisticated, indoors and outdoors exterior decoration of construction has been increased. However, it is very difficult to produce an FDM(Free-form Decorative Mold) that meets the requirements of quality, durability, and ease of installation, resulting in a high cost. Therefore, the objective of this study is basic research for economical production of FDM production technology while satisfying the above requirements. For this study, the authors analyze the details of the shape and requirements of the FDM, and the production details and processes that reflect the characteristics. The results of this study can utilize to develop algorithms for production and management of academically efficient FDM and can utilize to secure FDM production technology at commercial level.
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A Basic Study on the Improvement of Construction Management Engineer Placement According to WorkloadSince the introduction of the C.M(Construction Management)system in the Basic Law of the Construction Industry in 1997, the recent arrangement of construction management engineers in public sector buildings has generally been based on architecture·civilengineering·machinery·landscaping, electricity, telecommunication, fire fighting by the number of M/M(Man and Month). In the field of engineers arrangement in each field, the arrangement of M/M according to the workload of architecture.civilengineering.machinery.landscaping and electricity is inadequate causing conflicts and C.M among construction management engineers. Therefore, this study aims at basic research that is used to identify the problems through the questionnaire and to prepare future improvement plans.
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The government and the Korea Occupational safety & Health Agency have continuously carried out safety activities such as supervision, inspection, technical guidance and financial support in order to reduce safety accidents at the construction site. However, the number of disasters at construction sites is increasing every year. So analyze the results of the supervision and inspection of the Ministry of Employment and Labor, the projects related to the small-scale construction work of the Safety and Health Corporation, and the technical guidance project of the disaster prevention technology guidance organization. It is also necessary to establish an improvement plan for the disaster reduction of the small-scale construction work site for this project.
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In this study, it analyses the problems of the Fire Compartment in Goyang Bus Terminal. Based on analysed data, it is confirmed the necessity of the Smoke Compartment installation for Protecting the Smoke Spread in Large-Scale Buildings using of FDS(Fire Dynamics Simulation). In addition it suggest that the necessity of Smoke Compartment application method and Development of Design Guideline.
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The construction industry is a typical labor-intensive industry, and is heavily influenced by the employment structure. However, research on how the employment structure of construction workers affects the construction industry has not been sufficiently studied. In this study, the major factors influenced by the employment structure in the construction industry are derived and the causal relationship between the factors is illustrated. The results of this study are expected to be used as data for setting direction of policies related to the employment structure of construction workers.
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Recently, CM at Risk delivery system(CM@R) that could solve the problems of Design Bid Build delivery(DBB) system has been emerging. In the CM@R delivery system, the contractor negotiates for a maximum guaranteed price(GMP) with the client at the design stage, and the contractor carries out the construction within the GMP. In CM @ R, the construction company with expertise in construction participates from the design stage to reflects the construction know-how in the design. On the other hand, the modification design frequently occurs due to the change of the construction cost when negotiating the GMP. In addition, uncertainties are inherent in the GMP calculation because the calculation is based on unfinished drawings and documents. This study proposes a probabilistic GMP estimation method applying MCS to the BIM - based cost prediction model, in order to extract the accurate quantity information when estimating the GMP and to cope with the change of the construction cost inherent in uncertainty.
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The objective of this study is analyzing of requirements for improvement of the work-life balance of construction managers working in Korean construction companies. A survey has been conducted to analyze the requirements for improvement of construction managers. The survey was conducted on construction managers working in the field of architectural construction. 59 field managers working in 18 Korean construction companies responded to the survey. Upon analysis of the survey, the working hours were excessive and recreational time was very poor for the construction managers. There were differences in the answers regarding the areas that require improvement in the working conditions based on the age groups of the construction managers. A majority of young technicians selected that the recreational time and content of work require improvement, and technicians with a lot of experience selected that the stability of occupation and wage require improvement.
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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 concrete with three-hours-fluidity-retention performance are presented.
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The compressive strength of concrete is determined by various influencing factors. However, the conventional method for estimating the compressive strength of concrete has been suggested by considering only 1 to 3 specific influential factors as variables. In this study, nine influential factors (W/B ratio, Water, Cement, Aggregate(Coarse, Fine), Fly ash, Blast furnace slag, Curing temperature, and humidity) of papers opened for 10 years were collected at 4 conferences in order to know the various correlations among data and the tendency of data. The selected mixture and compressive strength data were learned using the Deep Learning Algorithm to derive an estimated function model. The purpose of this study is to investigate the effect of the number of hidden layers on the prediction performance in the process of estimating the compressive strength for an arbitrary combination.
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The In this study, the change of composition of the hydrates according to the recovery age of concrete in the case of fire damage was confirmed through microscopic analysis. In 28 days of age, the production of ettringite was higher than that of day 1, and the calcium hydroxide was increased in the 91 day. It has been recovered through the generation of major hydrates which affect the strength.
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In this paper, we investigate the characteristic of ASRC concrete with the addition of liquefaction red mud using red ud which can be used as an alkali activator of alkali-activated slag cement. as a result, the compressive strength and the efflorescence area increased, and as the amount of liquid red mud increased, the compressive strength decreased and the efflorescence area increased.
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The properties of concrete produced by ready mixed concrete company in Busan were measured. Because the concrete was mixed with blast furnace slag and fly ash etc., the compressive, tensile strength and chloride ion diffusion coefficient were lower than OPC concrete even though the specified concrete strength was same. If the durability about salt attack were satisfied, the concrete of lower specified concrete strength would be adopted to concrete mixing design. FEM analysis was carried out to predict the life time expectancy.
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This study is a basic review of the basic characteristics of mortar as a result of the use of concrete as a fine aggregate for CGS(coal gasification slag) generated from the IGCC(integrated gasification combined cycle). The analysis shows that CGS and crushed sand + seal sand mix is the best combination of CGS combined with about 75 % of CGS based on the effects of promoting liquidity and strength. This is expected to be a positive factor in securing the strength and flexibility of concrete given the optimal mix of CGS, and may also contribute to the improvement of quality.
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There are three types of high fluidity concrete: powder based, VMA based, and combined. In the case of the powder based high fluidity concrete mixture, according to the textbook, increased viscosity due to the replaced fly ash can prevent segregation of coarse aggregate. On the other hand, decreased density of the powder due to the fly ash replacement can causes segregation but there is no report on this issue. Therefore, in this research, the segregation resistance and segregation evaluation method for powder based high fluid concrete mixture are evaluated. As a result, with increased replacing ration of supplementary materials, EIS value was decreased and apparently segregation resistance was increased. However, from the compressive strength evaluation depending on height of the cylindrical specimen, it was confirmed that the different of strength difference between top and bottom part of the specimen. Thus, following research regarding vertical segregation should be studied.
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It was 15 years since the remodeling system was introduced in 2001 and the remodeling system was implemented due to the amendment of the housing law. From now on, the remodeling will be settled in the direction of important apartment houses, and planning will be the core plan of remodeling. Up to now, the remodeling system has changed according to the market situation, and the planning plan has also changed based on the laws and regulations. In this background, this study summarizes the changes of the regulations related to the remodeling plan and examines the characteristics of the plan according to the changes of the regulations. The remodeling plan can be divided into three periods according to the changes of the regulations, and the contents of the regulations and the characteristics of the plan have been clarified.
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In this study, the purpose of the study is to determine the depth of damage caused by early frost damage in concrete slab structures under the conditions of external temperature during winter. In other words, we intend to analyze the depth variation of the early frost damage as the thickness of the normal strength concrete slab members changes. As a result, the thinner the component was, the deeper the early frost damage was found to be, and the resulting increase in brightness of the concrete was delayed. and It is analyzed that under this test condition, an early frost damage was created with a thickness of 50 mm for the member and a thickness of 39 mm for the member of 300 mm.
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In order to compare the electrochemical performance with that of Calomel Electrode, MnO2 solid-state-electrode was fabricated and its potential and impedance were measured in chloride aqueous solution. As a result, the SCPS without chloride ions showed a potential of -200 mV or more and an impedance over 2000 Ωcm, but the potential below -600 mV and the impedance below -200 Ωcm showed as the chloride concentration in the solution increased. It is considered electrochemical studies on the corrosion of rebar are necessary for the MOE, which shows the same tendency as SCE and exhibits electrochemical performance, over the Mortar level in the future.
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Recently, a large fire has occurred through a dry bit, which is a flammable exterior material, in Daebong Green Apartment Fire in Uijeongbu in 2015 and Jecheon Sports Center Fire in 2017. In this study, KS F ISO 5660-1 Cone calorimeter experiment was used to examine the fire risk of dry bit. Also, the performance of the repair and reinforcement materials to prevent fire expansion was examined. As a result, the dry bit is likely to be ignited by internal and external flower gardens, and its combustion rate and calorific value are very high. In addition, the performance of heat resistance such as ALC panel and ceramic board as a repair and reinforcement material has been proved. However, the insulation is expected to require further consideration.
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In the domestic nuclear power industry, concern about safety of nuclear power plants is continuously increased with the Fukushima nuclear power plant accident. In order to enhance the safety of nuclear power plants, it is important to ensure that the power plants are operating with proper margin within the original design bases. Margin management is the process of ensuring that the NPP designer and operator are aware of the physical and operating limits, and potential and probability of failure, for each component in the plant. All components are subject to margin considerations, but the most important components by scope and attention are those related to safety-related systems and NPP safe shutdown.
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It is required that an evaluation method that can present the performance after remodeling to residents objectively as the increase in demand for remodeling. New construction is able to evaluate through housing performance grading indication system. However, there are some parts that are difficult to apply as assessment criteria of new construction in remodeling. The purpose of this study is to establish the assessment criteria direction for each item in remodeling performance evaluation. In conclusion, we set up institutionalized items for remodeling performance evaluation, and propose to assessment criteria direction based on the characteristics of remodeling on extracted items.
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Apartment houses are now a popular form of general housing, and the construction techniques and materials quality used to construct apartments are also continuously evolving as if they were representative. However, issues concerning flaws are constantly being reported in the press. This study attempts to analyze the trend of conflicts related to defects and to analyze the types of defects received in the apartment building, to suggest the development of the integrated defect management system, and to develop the construction based on the development of the system.
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The domestic construction industry is changing its preference for demand and supply along with urbanization and economic development. Accordingly, initial risk assessments is more important than before. Currently, the research related to risk analysis except for apartment studies is insufficient. Therefore, the objective is to suggest a basic study on financial analysis model development by applying optimization method in residential officetel. To achieve the objective. first, the previous studies are investigated. Second, the causal loop diagram is structured based on the collected data. Third, the financial model is developed by using optimization method. In the future, the proposed model can be helpful whether or not conduct execution of an officetel development project to the decision makers.
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Many researchers in South Korea have conducted regarding the safety climate and concluded that the safety climate effect on the safety performance. However, the survey tools that were used in domestic research were developed by individuals or designed by reconstituting, translating from previous studies. In addition, the safety climate as a low factor of organizational culture showed up in different types depending on business scale. In order to solve this issue, the objective of this study is to analyze the safety climate level of construction company depending on business scale in South Korea. first, the survey is conducted by NOSACQ-50 for construction workers. Second, it is analyzed how organizational culture affected the safety climate. Finally, the improvements are suggested on the level of safety climate. In the future, this study will be used as a baseline for the effects of the safety climate on the safety performance in construction site based on business scale.
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Every construction company should consider the apartment price when building apartment houses because the sales price has a great impact on the rate of apartment sales. Here, the average apartment price and characteristics of an apartment complex are factors that determine the sales price. However, the existing apartment pricing method fails to properly reflect the weight of each factor. Therefore, the study investigates factors that impact the apartment price and importance of each factor. It examines the apartment pricing method taking into account of the weight.
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The main focus of this study is the analysis of the importance of the planning work of apartment housing projects. Group the detailed work of the facility into five major tasks, categorize each into five major categories, organize the construction plans (P1 through P 6), name the plans (C4), and analyze the quality of the environmental management plans (E1 through E 4) Finally, this study derived major planning tasks from the correlation between planning and cost metrics and from the T-test.
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In this research, the feasibility of wireless senor for compressive strength evaluation was checked by applying on the actual apartment construction site with insulation formwork during winder period. As a result, there was no significant problem on monitoring the compressive strength of the concrete with the sensor. Thus it is considered that the suggested method can be an efficient method for the quality control at the construction site.
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The purpose of the research is suggesting the temperature compensation strength for Unicode of constructure standard from Ministry of land, infrastructure and transport. As a result, for the concrete mixture with 100 % OPC, 6, and 3 MPa of compensating strength values were necessary when the temperature were from 4 to 9℃, and from 9 to 17℃, respectively. Additionally, when the temperature was higher than 17℃, compensating strength value was not necessary. In the case of 20 % of blast furnace slag replaced concrete mixture, 9, 6, and 3 MPa of compensating strength values were necessary when the temperature were from 4 to 6℃, from 6 to 12℃, and higher than 17℃, respectively.
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Performance measurement and management in the construction industry has traditionally been regarded as the major factor for successful business execution. In addition, there is emphasis on the function of performance measurement and management that can early warn potential risks and poor performance in project execution environment changes. Previous studies have made various attempts to measure the quantitative performance of construction projects, and the research to derive the link between the results and the issue that can meet the future needs is expected to provide valuable information. The purpose of this study is to analyze the research trends based on the keywords presented in previous studies on the performance measurement and management of construction projects. Considering that the results presented in the existing literature can be an indicator of the evolution of the sector before it is applied to industry, the result of this study is expected to be used as a basic data to support the establishment of research direction in the future.
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Recently, a growing number of accidents have taken place at construction sites, causing serious casualties. To prevent accidents or minimize damage, it is necessary to develop the safety precautions education is essential. However, the effects of safety education do not have as much effect as the importance of safety education. so As a new direction, we are looking forward to effective education by simulating realistic environments using VR. The safety training method used to experience and learn dynamic situations in a limited room wearing HMD is combined with VR. It will be the start of the construction industry going forward.
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While damage caused by fire increases, awareness of fire is still low. Morever, Small fires often spread into big fires as they fail to keep the golden time due to the delay in initial response. In particular, the initial response is more important in areas where many unauthorized buildings are called " Panjachon " as firefighting facilities are insufficient compared to other residential facilities. Therefore, we will combine BIM technology, drones and IT convergence technologies to develop a firefighting safety information system that can speed up initial response and help combat fires.
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Unlike the projects that the government has implemented recently to develop new cities under the New Deal project, Saeddeul Village projects to improve the environment of the city are gaining attention. The problem has been found to be that many of the buildings in Saeddeul Village are still not earthquake-proof by using drones to review the state of the town. It also revealed that after two years of earthquakes, Pilotis structures are the most vulnerable to earthquakes. However, it is suitable for small spaces in the city because it provides parking spaces as well as residential spaces. Accordingly, the focus should be on repair and reinforcement rather than reconstruction. In this study, a concrete-based seismic design and construction method is developed in the columns of the existing pylotis structure.
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This study aims to provide a more comfortable environment for the external environment by designing a rotable dwelling that deviates from the conventional fixed residential concept. The round pillars, which are the center of the building, are constructed by placing the CFT (concrete Filled steel Tube) technique in place and assembling modular houses with columns. This study combines existing building techniques. Korea also needs to develop various related studies quickly.
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Decline in population and aging have led to the crisis of urban extinction, and the importance of urban regeneration has grown in the country. In addition to the meaning of redevelopment and reconstruction, the government will seek to secure sustainable living conditions, restore the economy, and restore social and cultural functions by utilizing the new technologies based on the efforts to restore the maximum cost to urban buildings and IT technologies.
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Recent construction projects have now regenerated the existing city rather than reconstruction or redevelopment to create a new paradigm. While the aged houses are reviewed to distinguish between the repair, reinforcement and reconstruction stages, the modular construction system makes the most of space using the modular system, and the projection mapping system is combined with the existing space. Therefore, we will proceed with the research so that improvement and correction of future issues can be made.
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The slabfrom, which is commonly used in construction sites, has drawbacks in that the workability of the workers is reduced due to their heavy weight. This study investigates the possibility of design optimization of euro form between structural stability and weight using harmonic search algorithm. The harmonic search algorithm is a metaheuristic optimization technique that obtains multiple optimal solution candidates through iterative. As a result of multiple attempts of optimization through the algorithm, it was possible to design the formwork which is structurally stable and light in weight than the existing formwork.
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For the concrete construction, finishing process is inevitable for crack control and improving permeability. The finishing process is closely related with setting time, but currently, the timing of the finishing process is not managed with scientifically but feeling of the workers. In this research, therefore, by comparing with the setting time measured with penetrating method, the feasibility of durometer for measuring setting time was analyzed. As a result, there was a high relationship between setting time measured with penetration method and durometer. Therefore, it is expected that using durometer can be a good solution for assessing setting time for finishing process.
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This study produced Portland limestone cement at the rate of limestone substitution by grinding limestone and clinker together, and it conducted an XRD analysis to determine the sign language response structure as a basic study on Portland Limestone Cement. As a result of the XRD analysis, the higher the substitution rate of limestone, the more likely it is that the detection rate of ettringite is decreased. Additionally, we could see that the production volume of Mono-carbonate was increasing.
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This study is a fundamental study to utilize CGS from the IGCC as a fine aggregate for concrete. According to the study, the chemical composition of KS F 2527 was reviewed. The results showed that the KS F 2527 standard was generally satisfied, but the content of the sulfur trioxide(SO3) exceeded the limit set by the molten slag. The possibility was found to be a fine metal based on chemicals other than sulfur trioxide(SO3).
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Tn this present study, the superhydrophobic surface was developed on the cement mortar surface by using water repellent materials. For better superhydropohicity, it was developed by using silane as binder and which was enriched with filler materials of SiO2 and TiO2 nanomaterials. Those nanomaterials enriched with silanes were admixed in cement mortar during casting time and another was coated on the cement mortar surface. The water repellent properties of spray coated and admixed cement mortars were evaluated by measuring the contact angle which was compared with normal cement mortar.
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The Research is underway to utilize heavyweight concrete for various applications. One of them is to use heavy concrete as a marine concrete such as a breakwater to resist wave. Marine concrete is often complex in shape and requires high fluidity. When the heavyweight concrete is high fluidity, there is a high risk of segregation due to the high density of the coarse aggregate. Therefore, we evaluate the fluidity of heavyweight concrete using heavy fine aggregate. As a result of the fluidity evaluation of the heavyweight concrete, the fluidity of the heavy fine aggregate was similar to that of ordinary concrete. Therefore, it is considered that the use of heavy fine aggregate in the development of high fluidity heavyweight concrete will be one of the methods.
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As part of the effort to shorten the construction period, this study examined the strength expression characteristics at the early age of concrete using high fineness cement and blast furnace slag. accordingly to provide a basic data on how to solve the problem that the initial strength is lowered.
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The purpose of this study is to evaluate the adhesion in tension of polymer-modified mortars according to curing conditions. From the test results, the adhesion in tension is seriously affected by type of curing conditions compared with type of polymer dispersions or polymer-cement ratios. The maximum adhesion in tension of EVA-modified mortar with polymer-cement ratio of 20% cured by standard condition is about 1.81 times, the cement mortar cured in water. It is apparent that the adhesion in tension of polymer-modified mortars according to raising of polymer-cement ratio is also much more improved irrespective of type of polymer dispersions and curing conditions.
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Chemistry and microstructure of steel reinforcement bars play an important role to control the corrosion in concrete environments. In present study, we have chosen two different microstructure of steel rebars produced from companies and assessed their corrosion characteristics in simulated concrete pore (SCP) solution with prolonged exposure periods. Hot rolled steel rebar showed more corrosion resistance compare to thermo-mechanically treated (TMT) one. The growth of passive is greater in hot rolled (A) than TMT (B) due to orientation of microstructure. TMT steel rebar exhibit distorted microstructure with many micro cells which enhances the galvanic coupling and induce the deterioration while on the other hand hot rolled rebars exhibit fine grain boundary which responsible in growth of uniform, adherent and protective passive film resultant improved impedance was observed.
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This paper investigates CO2 emission and cost analysis of blended concrete which was added with fly ash and slag. Three kinds of blended concrete were studied in this investigation, the first blended concrete was added fly ash replacing part of the cement while the second was added slag, the third was added fly ash and slag. Analysis result display that the blended concrete containing fly ash and slag is the optimal choice while considering economic and CO2 emissions.
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This study is a series of studies intended to derive the improvement of strength concrete quality using an emulsified refined oil (ERCO). In other words, ERCO is used to analyze the improvement degree of the basic properties of ordinary strength concrete by pre-adding the AE Agent on its products. ERCO was also planned to have a mixing ratio of 0, 0.5 %, and the pre-addtion of AE agent mixed with 0, 1, 2, and 3 % of the concrete's mixed ERCO mass. As a result, as the pre-injection of AE agent was increased, the slump, and air contents tended to be improved microscopically, but there was no significant effect. and Compressive strength tends to increase smart-all as the pre-addtion of AE agent increases in concrete, but it does not have a significant effect.
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In this study, the tensile properties of hybrid fiber reinforced cementitious composites under the high strain rate was evaluated. Experimental results, the HSF1.5PVA0.5 shown the highest tensile strength because the PVA fiber suppressed the micro cracks in the matrix around the hooked steel fiber and improved the pull-out resistance of hooked steel fiber. Thus, DIF of strain capacity and fracture toughness of HSF1.5PVA were greatly improved. Also, the fracture toughness was greatly improved because the tensile stress was slowly decreased after the peak stress by improvement of the pull-out resistance performance of hooked steel fiber at strain rate 101/s.
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In this study, the ultrasonic pulse velocity of the concrete cooled to room temperature after heating and the concrete during heating were evaluated. Also, the ultrasonic pulse velocity and mechanical properties of concrete were compared. As a result, the ultrasonic pulse velocity decreased when the concrete degraded during heating, and the ultrasonic pulse velocity of the cooled concrete decreased significantly. Which is consistent with the deterioration of mechanical properties of concrete.
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The cementitious composites have been developed to satisfy various demands of the construction market. The conductive concrete, which is a carbon-based cementitious composite, was used for the deicing or the detecting the internal crack. The cement-based battery is a technology that applies the basic concept of the alkaline battery to these conductive concretes. The cementitious composites could have a function as batteries, through a mixing of anode and cathode, which were consist of the zinc and manganese dioxide powder. The carbon-based materials, which have a significant effect on electrical properties, could be considered as the main variable in cement-based batteries. Therefore, in this study, the effects of carbon-based materials were investigated. Two types of materials, including the Carbon black and Multi-walled carbon nanotube(MWCNT), were considered as the main variables. From the experiment results, the electrical characteristics such as resistance, voltage, and current were compared according to the age.
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This paper has been researched that the earlier compressive strength of the cement pastes containing nano-TiO2 particle curing 1day, 3days and 7days. For the compressive strength measurements, all samples(dimensions 50×50×50mm) were prepared in accordance with ASTM C109. The compressive strength of the specimens with nano-TiO2 at the early age(1day, 3days and 7days) stage was lower than that of the reference group. Therefore, nano-TiO2 has little positive effect on the improvement of the compressive strength of cement pastes during early ages.
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The three kinds of tests are used to further study the effect of the amount of mineral powder in this mixture design. Firstly, comparing the relationship of the content of mineral powder and asphalt bitumen membrane thickness at different asphalt content, through film thickness to determine the range of gradation and asphalt content in laboratory tests, Grade A and Grade D, asphalt content 2.6%, 3.4% and 3.8% are set for the benchmark, then fatigue properties of the test are carried out in the established range, the result show that asphalt film thickness decreases with the addition of mineral powder. The result also show that fatigue properties of asphalt rubber mixture will reduced, when mineral powder added in, especially when the asphalt content is high.
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This study analyzed the unit weight and compressive strength properties of lightweight concrete using high volume blast furnace slag powder by the mixing ratio of lightweight coarse aggregate to investigate the properties of lightweight concrete using domestic artificial lightweight aggregate.
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Test results showed that foaming ratio of autoclaved aerated concrete significantly affected by the CaO/Si2O (C/S) molar ratio of the component materials, indicating the greatest foaming ratio of 202% when the C/S ratio was 0.9.
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Recent government policies are increasing interest in zero-energy housing, a building that minimizes energy consumption (90% reduction). As the importance of building passive performance is emphasized, the role of insulation is increasing as a way to reduce indoor heat loss in order to minimize the use of cooling and heating energy. There are two main types of insulation. Organic insulation is widely used for various construction structures such as construction and industrial due to some merits such as the convenience of construction and construction cost. However, it has been pointed out as a main cause every time a fire accident occurs, Jecheon Sports Center', the fire damage of buildings caused by the use of organic insulation materials is expanding to social problems, so it is urgent to research on nonflammable inorganic insulation materials.
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Modern people are more interested in the indoor environment as they spend more time indoors than in the past. Among the air pollutants in the indoor air, ladon gas is a colorless, tasteless, odorless, inert gas produced by nuclear decomposition of naturally occurring uranium in rocks and soils. It has been proven that ladon gas is introduced into the room through cracks on the floor of the building or basement wall, and it causes various diseases such as lung cancer when exposed to radon during human breathing. The US Environmental Protection Agency (EPA) specifies 4pCi / L as a necessary measure for radon, and the Korea Environmental Protection Agency has implemented comprehensive indoor radon management measures since 2007. Therefore, in this study, we intend to adsorb and reduce radon in indoor air pollutants.
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Recently, as the interest of the government and the public on energy saving has increased, the airtightness of buildings has been improved to improve the insulation performance of buildings. However, indoor air pollution due to increase of pollution source in indoor space and lack of ventilation is increasing and interest in indoor air quality is increasing. In 2003, the Ministry of Environment enacted and promulgated the Act on Indoor Air Quality Control in Multi-use Facilities. Radon is a naturally occurring radioactive inert gas with colorless, tasteless and odorless nature. The concentration is high in a room where radon can not escape. Although lononggas is naturally occurring, it is not interested in living environment, but it is easily inhaled through human body through respiration and causes lung cancer in long-term exposure. Therefore, this study intends to carry out an experiment for the reduction of radon gas, which is the first carcinogen in indoor air pollution sources.
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In the construction industry, we have set goals such as reduction of greenhouse gas emissions and reduction of energy use. In particular, reduction of CO2 emissions in the concrete manufacturing process, reduction of industrial waste and industrial wastes into concrete The zero-emission level of reuse as a resource is under review. On the other hand, the cost of stone is expensive due to small quantity production of domestic stone production in order, it is difficult to carry and construct with heavy material, and it takes long time to construct. In order to solve the shortage of supply and demand of natural stone, various kinds of stone powder, artificial stone made by putting stone texture on the surface of mortar or concrete, fiber reinforced plate, tiles and the like are increasingly used. In this study, the artificial stone using slag and recycled aggregate instead of natural stone was fabricated and the strength characteristics were evaluated for its applicability and feasibility.
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Recently, the danger for radioactive materials has become a hot topic. Beginning with the Chernobyl nuclear accident in 1996, in 2011, the Fukushima nuclear power plant in Japan suffered major damage such as large-scale casualties and radioactive dangerous area selection. Concerns about leakage of radioactive materials due to recent earthquakes have been deepening in Korea, such as Wolsong Nuclear Power Plant in Gyeongju, and there is a growing interest in the safety of radioactive materials through the media and the media. However, the route to exposure to radioactive materials is not limited to these large-scale nuclear accidents. Typical examples of this are radioactive substances exposed in daily life. In the case of radon gas, the danger is being revealed through current events programs and news, and natural radiation exposure is attracting attention.
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Among the recent environmental pollution, indoor air pollution has an adverse effect on the health of indoor residents. Radon, one of the causes of indoor air pollution, is released from concrete, gypsum board and asbestos slate among building materials. Radon is a primary carcinogen and is a colorless, tasteless, odorless inert gas that adheres to airborne dust and enters the body through breathing. At this time, there is a risk of developing cancer if the alpha rays from the lononggas entering the human body destroys the lung tissue and is continuously exposed to a high concentration of lonon gas. The World Health Organization (WHO) has emphasized the reduction of radon and its exposure to radon by classifying it as a first-level carcinogen, but many people have not recognized it yet, and the research is underdeveloped. Therefore, this study was carried out to investigate the properties of adsorbed coconut radon to prevent the inflow of radon gas, which is an air pollution source of indoor air, and to prevent inflow into the human body.
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The development of insulation,the most important factor, is slow. The curtain wall market is getting bigger as the bulidings are getting bigger, but the insulation of the window is getting a problem. In order to solve this problem, we want to develop the insulation block used in the window frames. We will examine the insulation effect by using the existing Azon insulation block and the thermal worm convex which is to be developed with Therm 7.4 program.
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The aim of the research is evaluating a fundamental properties of mortar with atomized molten slag to develop a hardener for dry soil paving concrete. According to the analyzing results, comparing OPC, more favorable strength characteristics were obtained, while it showed rapid setting when the mixture contained more than 10 %. Therefore, when the atomized molten slag is used as a hardener, appropriate retarding process is needed.
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This paper presents the synthesis results of CaO-Al2O3 system clinker using the CaCO3 and the Al2O3 according to the synthesis methods dependent on the temperature. The purpose of this study is the formation of the CaO-Al2O3 system clinker containing high ratio of CaO·2Al2O3 (CA2). The maximum sintering temperature for the synthesis of CaO-Al2O3 compounds was 1250℃, 1300℃ and 1400℃. The CaO-Al2O3 compounds was sintered at the maximum sintering temperature for three hours. After sintering, the compounds was analyzed using X-ray diffraction method. The 12CaO·7Al2O3 (C12A7) and CaO·Al2O3 (CA) increased as elevating the maximum sintering temperature whereas the CA2 decreased. Especially, at the 1250℃ of maximum sintering temperature, the un-reacted CaO and Al2O3 was identified.
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In this paper, we tried to find the proper ratio of industrial byproducts which can express mechanical characteristics similar to ordinary portland cement by varying the ratio of industrial byproducts. as a result, the activated slag binder produced by the industrial byproduct in this study increased in compressive strength as the ratio of blast furnace slag increased and the fly ash ratio decreased.
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This study focused on the fact that there are a lot of alleys in some areas of the Urban Renewal New Deal project. In this study, we proposed a method to construct a spatial module by combining small modules. It is expected that the combination of small modules developed in this way will help revitalize the New Deal of Urban Regeneration. In the future, additional joint details will be developed, structure review will be conducted.
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This paper is a multipurpose functional synthetic resin formwork which can replace existing euro form. We tried to improve the disadvantages such as work noise, stenosis, recyclability, and workability of Euroform system. As a result of the test, Euroform showed an average of 106.7dB and synthetic resin formwork showed an average of 100.4dB. Therefore, it is considered that the synthetic resin formwork has a great effect of noise reduction compared to the euro form.
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In order to secure the variability of long-life housing, dry walls are used. The composite gypsum board panel is the most frequently used infill system for the wall, and it is an excellent construction method in terms of constructability and economic feasibility. However, there are also problems such as the destruction of Ondol pipes at the bottom floor and being unable to fix the light weight steel frame (M-bar) when a variable composite gypsum board panel is used. To solve such problems, a wall with a method of fixing only the top part without fixing the bottom floor is developed, but it is difficult to identify the durability of ceiling frame according to the tensile force of stud and the safety according to the Stiffness and impact resistance (soft body) of ceiling frame. Therefore, this study verified the effectiveness of infill system for the wall by conducting experiment on the stiffness and impact resistance of composite gypsum board panel according to the reinforcement of ceiling frame (wooden frame, double saw-toothed bracket, Cross M-bar). As a result, it was possible to secure the safety of wooden frame while the impact resistance and the Stiffness of double saw-toothed bracket and cross M-bar were not secured.
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To control the floor noise generated in the apartment building, a method of reinforcing the floor at the floor is applied. However, since existing buildings are difficult to reinforce upper generations, the ceilings of lower generations should be reinforced. The purpose of this study is to analyze the reduction effect by measuring the impact noise after reinforcing the floor soundproofing material on the ceiling of the existing building. In order to ensure the economical efficiency and flame retardancy of the products used as building interior materials, the existing polyurethane foam was impregnated with mineral to prepare test specimens and attached to the concrete slab surface. As a result, it was shown that heavy impact sound can reduce 2dB~5dB and light impact sound can reduce 4~8dB.
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Cool roof coating materials generally use white color which has the highest reflectance, but it is a tendency to apply various colors because it can cause glare and fatigue of a nearby building user due to the urban beauty and high reflection. This study when applying color diversity material cool roof coating was carried out as a basic research for the degree of solar radiation reflectance change. Experiment result. As a result of the measurement of the reflectance of each specimen, white showed the best reflectance in the near infrared region, and black had the lowest reflectance. Also, in case of brown, it was confirmed that the reflectance of solar radiation in the near extrinsic region is lower than that of gray.
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In the construction industry, a variety of Root-Resistance Waterproofing Sheets ar being developed and studied. However, defects still occur in the sheet. In this study, the performance of the navigation is studied by Root-Resistance. As a result of the test, no piercing or penetration marks were found by root in all the specimens.
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In this study, to confirm the performance of gel type urethane (hereinafter referred to as urethane gel) developed for the purpose of securing waterproof stability after application by increasing compatibility with asphalt mastic film material, general urethane coating material and adhesion. As a result, gel type urethane showed "all right" in fatigue resistance test.
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PTFE(polytetrafluoroetylene) is widely used as representative sliding friction materials, but there could be difficulties in applying it to various industry fields by the shortage of carrying capacity under high facial pressure and by the change of friction coefficient according to the environmental conditions. Accordingly, this study was to do comparative analysis on the friction coefficient by environmental temperature at the same facial pressure of UHMWPE which was mainly used as sliding friction materials under high facial pressure. In addition, this study was to proceed with the double shear structure by using two test specimen in order to minimize the frictional forces.
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This study evaluated the compressive strength, freeze-thaw and sulfate resistance characteristics of concrete using CFBC-Ash. The CFBC-Ash was adjusted to a particle size of 75 ㎛ or less and using by increasing the fineness of powder through milling. As a result, it was confirmed that the concrete using CFBC-Ash shows a high compressive strength, durability. Also, it is confirmed that CFBC-ash can be used as a concrete binder.
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In this study, the quality of recycled aggregate for concrete was investigated as the number of recycled aggregate crushing cycles, grinder and crusher, peeling and crushing. First, the quality of density, absorption ratio and solid content was improved as the separation distance decreased and the number of crushing increased, depending on the number of crushing of recycled aggregate and the distance between mantle and cone cave. The quality of density, absorption ratio and solid content was improved as the wire mesh used in striking plate and the number of hammers increased, depending on the type of striking plate and the number of hammers.
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Recently, interest in making nanocomposite materials for construction utilizing the excellent physical properties of nano materials is increasing. In this study, basic properties of mortar were evaluated by the dispersion condition of cellulose nano-crystals (CNCs) extracted from nanocellulose and the feasibility of the study was examined. As a result, it was confirmed that the flexural strength and the compressive strength were increased by increasing the dispersion time of the CNCs and by using the ultrasonic dispersing device and the magnetic stirrer together.
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In recent years, active loess cement has been used instead of cement in order to reduce the amount of cement and industrial byproducts that are the main cause of environmental pollution. We also used polysilicon sludge as a by-product to reduce the amount of cement used and to improve the environmental pollution due to the reduction of carbon dioxide. Polysilicon is a raw material used in the production of panels for solar power generation. When producing 1 ton of polysilicon, 2 tons of sludge is generated. It is an experiment to reduce sludge treatment and cement usage. This study analyzed basic characteristics of polysilicon sludge and active loess cement according to replacment ratio.
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The purpose of this study was to analyze the thermal performance of a cladding system which developed for easy maintenance and flexibility and installed on a long-life housing. The developed cladding systems were finished mock-up test at an authorized certification laboratory and were satisfied with the standard of the external wall system. The surface temperature and linear thermal transmittance of the cladding system were investigated by using the THERM as a simulation program. The joining part between the cladding systems had a weakness of condensation resistance. The surface temperature of the joining part was improved by filling and adding insulation.
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Urea is liquefied when it is dissolved in water and has the effect of increasing water. It is known that when using urea, it is generally possible to reduce the number of design units in order to ensure the same flow-ability, because the effect of increasing the water when using urea in the manufacturing of concrete is known. In this study, the change of basic properties of concrete when using urea was investigated in concrete production, and the effect of reducing the unit yield was confirmed.
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As the supply and demand of natural aggregate becomes more difficult in the domestic construction site continuously, many studies related to the recycled aggregate produced in the construction waste are going on. However, because of the safety and performance of the recycled aggregate, it is not used as aggregate for the structure, and it is mainly used as a nonstructural material. In addition, as the "recycled aggregate quality standard" has been revised in 2017, quality standards for various properties of recycled aggregate have been adjusted, and production technology suitable for recycled aggregate quality standards for concrete is needed. In this study, to improve the quality of recycled aggregate, we applied multistage wind pressure treatment method to the existing recycled aggregate production facility and compared the density, absorption rate, particle size before and after recycled aggregate treatment. As a result, quality criteria in various properties were analyzed satisfactorily.
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When IGCC Slag(CGS) aggregate was used as PHC-Pile, the moldability was lowered as the mixing ratio increased. concrete mix design. Also the mix characteristics increased the use of AD depending on the usage rate, however, require detailed consideration.
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Ultra high performance concrete(UHPC) represents high early age autogenous shrinkage strain due to its low water-to-binder ratio(W/B) and high fineness admixture usage. It has been reported that fiber can control restrained tensile stress and crack. The purpose of the present study is, therefore, to investigate the autogenous shrinkage as well as mechanical properties including compressive strength, flexural strength and modulus of elasticity on the UHPC with fiber type and pre-mix of binder.
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Improvement of insulation performance of buildings is a major part. Adiabatic method The adiabatic method minimizes the heat loss of the building. External insulation uses insulation to prevent fire. Ambient air hazards are less prone to fire. When a fire occurs, a phenolic pattern is formed and bond strength with the wall increases. EPS insulation and phenol foam were used to compare external heat transfer and external heat transfer. The heat transfer properties of phenolic foam and styrofoam were evaluated as follows. In the mortar and styrofoam structure, the problem of styrofoam reaching the burning point occurred before the collapse of the mortar, and the phenol foam had a problem in that when the direct fire was continued on the phenol foam. The characteristics of continuous infiltration appeared. In the case of mortar and phenol foam + styrofoam, the heat penetrated into the interior due to the shrinkage due to the shrinkage of the carbon screen on the phenol foam. However, when reinforced with glass mesh on the outer surface, And to reduce infiltration.
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The waterproofing material can be roughly divided into a coating material and a sheet waterproofing material. In the case of coating waterproofing materials, sheet waterproofing materials, which are easy to use in terms of workability and quality control, have been recently used because of their incomplete use of coating thickness, long curing time and poor blending due to in situ blending. However, in the case of the sheet waterproofing material, since the sheet overlapping portion is inevitably generated, various defects (breakage due to the behavior) are frequently observed. Therefore, it is imperative to establish fundamental measures to minimize this.
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Recently, apartment houses are becoming more and more sophisticated and attention has been focused on the design of the interior of the bathrooms. As bathrooms always use water, the importance of waterproofing is very high. However, there continues to use the method that was used 30 years ago. And no one was trying to improve. It is necessary to be converted to a dry method, because waterproofing methods and materials have developed. Therefore, this study proposes the required performance before applying the dry waterproofing material to bathroom.
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The rear side surface of tiles act have protrusions that helps secure the adhesion between the tile and the mortar for tile setting. Conventional height of the rear side usually ranges between 1 to 1.5 mm, and the molding method is classified in between press type and compression type during the manufacturing process, with most tiles being produced by the former method. In sites where adhesion failures were observed, tiles were taken to examine the cause of defect. It was determined that height was irregular at the rear side surface. Based on these findings, an experiment was conducted to determine the correlation between the rear surface and the bonding strength of tiles.
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The purpose of this study is to provide basic data of government policy by evaluating the competitiveness of construction infrastructures by country. The results of this study are as follows: Among the 20 countries, Korea ranked the 10th in the construction market stability, 12th in the construction system, and 10th in the infrastructure, 12th in the overall construction infrastructure competitiveness.
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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 7th in construction competitiveness, 13th 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 7th overall.
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The purpose of this study is to analyze the trends and changes in the environment of construction technology and industry through big data analysis and to draw out implications. Based on this research, this study will be used as a basic research for the vision of industrial competitiveness in the field of construction engineering technology and the policy task.
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The purpose of this study is to find out the requirements for pushing the existing stick-build method modularly in the bidding stage and use it as a basic research to quickly determine whether to apply the bidding stage modularity.
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Nowadays, the construction industry utilizes 3D models in the designing process, on which research is being conducted to establish an automated system for project cost estimation in connection with information related to construction such as material unit costs and wages, beyond the level of design interference review and construction quantity estimation. In this process, the project cost is estimated in connection with unit price data after takeoff the quantity based on the 3D model attributes and data types. A way to reduce cost and risk would be first developing prototypes of some of essential buildings and works, comparing and validating the outcomes, and then extending to the whole scope, because estimates differ on the basis of the scope and level of 3D design models as well as the data accuracy. This study analyzes case studies of project cost estimation by computing the quantity on the basis of 3D model in the construction industry and explores methodologies and management measures applicable for estimating nuclear power plant construction project costs.
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Due to the decrease in infrastructure investment and stagnation of overseas construction, it is concerned the instability of the construction market. Enhancing the Korean construction competitiveness, productivity improvement could be the breakthrough. In addition, defining construction contents utilizing virtual reality technology is drawing attention along with the trend of the fourth industrial revolution technology development toward the labor productivity improvement. This study conducted a survey to figure out the present state of the productivity management in field and comprehend the factors influence on construction productivity for further Korean construction productivity data platform.
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The construction liability type CM has been introduced in the form of a pilot project through public institutions since 2017 since it was introduced in the term of construction responsibility type construction project management in the Basic Law of Construction Industry in 2011 with the aim of improving the constitution of the Korean construction industry and strengthening global competitiveness. Through the introduction of construction-responsible CM, the government intends to change the paradigm of the overall construction industry, including design and construction, construction costs, disputes between stakeholders, and transparency of business. In this regard, the study aims to compare and analyze the evaluation methods on the bidding guide that public institutions (LH) are currently using to select companies in order to lay the foundations for successful construction of construction-responsible CM ordering methods.
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Construction industry is the biggest employer as a single sector, however, that needs better job quality and working conditions due to problems such as lack of job stability, aging worker, late disbursement of wages, and so on. In order to deal with fundamental issues of construction skilled worker's wages, this paper performs comparing the wage system of the construction industry in South Korea and the United States, and analyzes the characteristics about wage structure and determination. As a result of this study about U.S. case, it requires all stakeholder's exertions through technical competitiveness and management ability, not price war by reducing laborer's wages.
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This study analyzed the major revision factors and revision contents for 'Construction-Standard-Production-Rate for Construction Works in 2018. Part 16. Pipe Laying Down and Connection" which was revised by the construction expense estimation standard's middle and long-term plans. The main reasons for the revision was analyzed to be unclear construction scope, limitations in applicable pipe material based on the facility type, labor force mainly composed of ordinary workers, limitations of labor force, and incomplete appropriation standard for the tool rent fee and equipment expenses. Through revision of factors, common items were newly established, organization was revised, the labor force was mainly composed of the technicians, and basis for appropriation of equipment expenses was arranged. In addition, through periodic revision, the appropriation standard for bend and special pipes was set. Consequently, more practical construction cost estimate standard is arranged through revision.
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Study on Construction-Standard-Production-Rate for Waterproof Work Based on Site Construction StatusDevelopment of waterproof methods and materials resulted in the huge changes in waterproof construction materials. In consequence, the construction-standard-production-rate underwent overall revision in 2018. Especially, from the development of the specification standard and construction methods, the waterproof construction which had lower applicability in the existing construction production rate was revised. The construction methods which did not have applicability were removed. In addition, as there was a material difference based on parts, the constructionstandard-production-rate was revised by distinguishing vertical part and floor. Furthermore, by suggesting more clear work extent, the practicability in creating the standard for calculation of the estimated price in the construction field will increase.
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In Korea, The thermal resistance test of window sets is performed according to KS F 2278 standard, and is performed only on a specimen size of 2000 × 2000 (mm). In this study, a standard panel measuring 4000 × 3000 (mm) size was used to measure the heat flux in each part of the specimen, and to calculate the resistance to heat transfer And to seize whether the KS F 2278 standard is applicable to large Specimen.
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Construction automation is needed to improve construction productivity. 3D printing is a key technology of the 4th industrial revolution, and when applied to the construction field, the ripple effect is very large. In this paper, we propose a 3D printing method that can predict the 3D printing process and estimate the construction duration for each process. Through literature review and expert consultation, eight 3D printing activities for structure work were derived. Construction duration and cost estimation for each activity will be needed in the future research.
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This study compared the labor productivity of the construction industry to the manufacturing and service industries. In addition, It analyzed the construction labor productivity gap of the G7 countries based on data from the Korean Productivity Center. A comparative analysis of construction labor productivity between manufacturing and service industries, based on statistics from the National Statistical Office, revealed a relatively low level and trend of continued decline. In addition, a comparative analysis of the productivity of construction workers in the major G7 countries found that the difference in productivity is very large, with an average of 65.3 %. Therefore, domestic construction companies and the government should prepare Improvement measures to improve productivity by investing in technology development to increase labor productivity and improving the production system of the construction industry.
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As global climate change leaded to extensive natural disaster and radical deterioration of infrastructures, there was increased attentions for the evaluation of infrastructures. After the collapse of Seongsu Bridge in 1994, Korea has enacted the "Special act on safety and maintenance of facilities" and secured the safety of facilities using systematic and periodic safety inspections. However, current facility inspections are mainly performed by the physical defect and structural analysis, and do not properly consider the serviceability of infrastructure such as capacity of facility and user's satisfaction. Thus, the purpose of the study is to develop an evaluation criteria for serviceability of infrastructures and finally leading to the revision of "Special Act on safety and maintenance of facilities in rational manner.
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A Study on the Items on Checklist of Design for Long-life Housing Considering the Construction StageThe long-life housing certification system must have been applied more than 1,000 households apartments since 2015. The basic design guideline for the popularization of long-life housing has been developed in 2017, which include the concept of long-life housing and basic principle of design long-life housing. The demonstration project of long-life housing is be currently under construction in Sejong-si. The aim of this study is to find items on design checklist considering construction stage. The main goal is the development of design manual of long-life housing.
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Thailand and other Southeast Asian countries are experiencing frequent floods due to heavy rainfall and are using the Flood Rapid Defense System(FRDS) for an emergency. However, they are expensive and has a wedge-shaped panel suitable for the dirt bank, making it unsuitable for applications in Southeast Asia, a relatively underdeveloped country. In this study, the direction of development of FRDS was derived through domestic and overseas case analysis. Future studies should be carried out to develop the actual FRDS according to the development directions presented here. These results will be effective in preventing flooding of buildings in Southeast Asia as well as in Korea.
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Protective coatings at nuclear power plants should be designed to withstand exposure to ambient conditions during normal operation or design-basis accidents. However, there was a change in the perception of the protective coating to the revision of the Regulatory Guidelines by the NRC in July 2000. In other words, maintenance guidelines have been strengthened in order to minimize the clogging of the cooling water system due to the substances in the containment building. Therefore, KHNP, the contractor and operator of the nuclear power plant, plans to develop the coating system for nuclear power plants in accordance with the regulation, and plans to develop its own coating expert.
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In the past, the results of window cleaning work have been judged subjective and complaints about cleaning results are being raised. In this study, we tried to quantify the evaluation of the cleaning result. For the quantification of the evaluation, a colorimeter was selected and the basic experiment was carried out. In addition, this study examined the use of standard dust powder for artificial production of contaminants in glasses. Further evaluation and analysis will be carried out to quantify the evaluation criteria of the cleaning results.
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Recently, the supply and demand of aggregate in the Southeast region has been disrupted because supply of sea sand decreased due to discontinuation of collecting the EEZ aggregate in the southern sea. This study analyzed the Trends of Supply and Demand of Aggregate in the Southeastern Region of South Korea in order to find a solution these social problem.
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It is expected that the proportion of crushed aggregate will increase in order to fill the decreasing supply of sea sand in the southeast area. However, it is necessary to supply the least amount of sea sand to diversify the aggregate source, in order to minimize the mixing ratio of sea sand and crushed sand to minimize the structural stability of the concrete.
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The problem of imbalance between supply and demand of fine aggregates in the southeastern region due to the decrease in collection of EEZ(Exclusive Economic Zone) sea sand has been raised. In this paper, the possibility of securing alternative aggregate as a means to solve the problem of fine aggregate shortage in the southeast region was analyzed. As a result of the analysis, the alternative aggregate is easy to manufacture and its quality can be secured. And, it is suitable to use as an aggregate with less environmental burden. In addition, institutional improvement measures are needed for effective utilization and recycling of alternative aggregates.
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It's prohibited to take sand from southeastern EEZ(Exclusive Economic Zone) from January 2017 in korea. So, the supply of sea sand has been decreased and costs of sea sand are rising as a result in the southeast region. This paper deal with appropriateness of the taking sea sand, circumstance and fisheries damages by extraction of EEZ sand and proposed control measures for ensuring quality of sea sand and consider fishermen support plan for ensuring a stable supply of sand in southeast region of korea.
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The master plan for aggregate supply and demand aims to ensure the feasibility viability of mid/long-term aggregate supply and demand by establishing comprehensive plans for regional groups and aggregate types. In addition, It will propose ways to reduce the environmental impact of the development of aggregates and to stabilize aggregate supply and demand across the country. Also, it will seek to promote the stable development of the construction industry through policy and related amendments.
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This study discusses the development of asphalt based waterproofing sheet applied on the blind side of the concrete substrate. The inorganic coating membrane is applied on top of the waterproofing sheet surface for protection, and adhesive bond to the concrete substrate surface is secured via hydration reaction the cement. The study reveals the experimental results of the overlap section tensile strength to observe the effects of the adhesion strength of this material.
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In recent years, residential apartment building parking lots are built in underground spaces, and with conjunction to improve the environment of the urban area, artificial greeen roof systems are installed on the upper slabs. However, early plant growth are resulting in root penetration into concrete cracks and in turn into the waterproofing membranes, leading to degradation and damaging of the waterproofing system and structural durability. This issue highlights a problem of conventional maintenance system of concrete structures, and proposals for amendments follow. In this study, a waterproofing and root barrier construction design for the upper slabs of residential building underground parking lots is proposed, and motioned to be added into future construction specifications.
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Contemporary concrete structures make use of underground spaces as parking lots and other comfort facilities for efficiency purposes. As underground environmental conditions are in constant exposure to degradation factors from the environment such as groundwater, hydraulic and soil pressure, structural movement and settlement, structural defects in the form of leakage occur. Current maintenance regulations and regimes are unable to respond to this field, as degradation mechanisms in underground environments are still unclear. In this regard, this study proposes the utilization of integrated information sharing system that can provide various technical information for construction designs to prevent leakages in underground concrete structures.
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Waterproofing materials and construction methods have been developed and applied to various construction sites since the past. However, there many cases where the waterproofing performance is not satisfactory, leading to continuous water leakage. It has been observed that a key reason for this is because waterproofing method and material selection is not optimized in terms of the appropriate application area and environmental degradation factors. This paper proposes that future selection of waterproofing methods should consider the following evaluation criteria; 1) waterproof performance evaluation according to site conditions, 2) evaluation of construction method, 3) manufacturing and maintenance of waterproofing systems.
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This study proposes a standard method of diagnosis and repair to prevent and maintain the problem of durability deterioration caused by leakage cracks in apartment basement structures in Korea. Following the announcement of the previous maintenance plan section, this is the second part of the study, focusing on inspection of methods for diagnosing and repairing leakage cracks in apartment basement structures. In this thesis, the matters required for the procedures, types, times and equipment of the inspection plan and the inspection methods, records, and decisions required for the actual inspection are described.
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In this study, various materials such as epoxy material, urethane material, cement material, and acrylic material are used to solve the water leakage occurring in underground structures. However, in the reality that the durability is insufficient and the effect is insufficient, it is aimed to improve the repairing effect by using cement and acrylics n combination. As a first study, we tried to verify the performance of rapid micro cement and cement paste and to improve the performance by checking the product properties. Three types of micro cement are evaluated. Three types of micro cement are used: fiber inclusion, fiber unfolding, and cement paste. When the material is selected for micro cement, it is applied to the field to understand the maintenance effect and durability.