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
2011.11a
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Defect dispute has been a continuous claim that concerning a apartment building. However, objective standard of judgment is inadequate to solve defect dispute. Furthermore, it need to scientific evidence that composited standard of judgment. This evidence has a necessary to collect a data for a long time and systematically analyze. Therefore, it need to develop smart information management system, in this study, it review user-oriented condition as swot analysis.
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The use of foreign labors was inevitable at the construction site in Korea. Most construction companies are being used them in the workplace due to the cheap labor, but their work ability are insufficient as much as Korean labors. In this paper is expected to confirm the foreign labors' employment conditions and study to analyze the changing of foreign labors' work ability.
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Domestic construction industry suffered from the IMF and makes a great effort to improve in 'cost management', 'strengthening the competitiveness of the construction industry'. Therefore, the industry has become interested in improving the productivity of construction and ongoing research is being progressed in various angles. In such circumstances, the needs for a study of concepts and space of the actual construction work place is emerging. This study were utilized BIM to understand the types and causes of problems in space during the finishing work in construction and categorize importance and frequency of occurence through a survey of experts and AHP to analyze the realtive effects of importance then modeling to them to aware of issues and give direction for efficient management. This study is anylize the problem which is caused by same time process in finishing work progress of apartment applied by BIM. and categorize the type of work interference management in finishing work, and anylize by the type of occurence then predict the work interference management through in BIM 3D VIEW and suggest the solutions.
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The Construction Standard Production Unit(CSPU) has been used for the standard cost estimate in public and private construction projects. However, It is difficult to reflect the various site attributed variation in productivity using existing CSPU. The reason is that a criteria which site should be selection for enactment and/or revision of CSPU is not established. This study aims to provide essential data to be used for analyzing the labor factors in a way to secure efficiency and reliability of CSPU.
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The main purpose of this research is to propose standardization of construction components design with BIM and to develop WLCM Framework and Application System for supply chain management on interaction of stakeholders based on proposed standard component. To accomplish main purpose of this research, we planned three years period, in first year, we will develop model for building lifecycle based on BIM, and this model can give the chance of collaboration with stakeholders of building project. In second year, we will develop WLCM system with model, and to improve performance of application model/system. This study can contribute on reduction of whole lifecycle cost, with preventing omission of factors on cost reduction possibility, develop concurrent engineering framework for construction stakeholders with proposed BIM.
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Construction automation and robotics are being taken notice as an alternative to improve productivity and quality. Reflecting on these purpose, automation system, called RCA(Robotic-crane based Construction Automation) system, is developed and have been verified through a pilot project recently in Korea. To apply the RCA system in high-rise building effectively, each management factors of element technologies in the system is derived and assessed critical factor. The purpose of this study, management factors of element techniques, consisted of RCA system, is classified through questionnaires/interviews targeting system developers and construction managers in pilot project site, and critical factors is selected using AHP.
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Over the past 20 years, Researchers have tried to develop "Integration Model of Cost and Schedule" in construction industry. They suggested various models and techniques, however, it is still required to develop new methodology for AL Form Work in Public Multi-Housing Projects. Accordingly, this research focused on measuring quantity take-offs of on-going projects and analysing the basic process of using the resources(Labor, Material, Plant) related to cost and time data. There are 3 steps of this research : 1) The literature review of previous studies about Integration Model of Cost and Schedule was conducted. 2) Model for integration between cost and schedule was developed. 3) the accuracy of developed model was verified. The results are expected to improve in integrated managing the cost and schedule data of AL form work.
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Recently, the development of alternative energy technologies has been actively conducted for energy conservation and CO2 emission reduction. Especially, photovoltaic energy has been applied practically in construction industry, and research on the building-integrated photovoltaic system (BIPV) that can replace fossil fuel for building operation and maintenance has been performed. However, this vibrant research has been limited to the use phase of buildings, and few studies have been carried out in the construction phase. The construction duration and the scale of the sites have increased along with the high-rise trend of buildings, and it is forecasted that the temporary electricity use and CO2 emission in the construction phase is increasing. In sight of these developments, this research analyzed applicability of the photovoltaic system for the construction phase that can replace the electricity used on the high-rise construction site.
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The purpose of this study is suggesting a basic data for which scientific preservation and rehabilitation of future modern architecture through the analyzing property of clay brick used in modern architecture in a scientific way.The clay brick which is used in the early 1900s has even lower property than present clay brick because of poor plasticity technique at that time. It could be possible to property and effective stability examination of modern architecture from nondestructive testing is significantly associated with property.
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The objective of this study is to develop the prototype system for microwave heating in a manufacture process of alkali activated Hwangtoh binder as replacement materials for the cement in concrete. In order to achieve this, four research phases are carried out as follows: 1) establishment of a system concept 2) deduction of a system element 3) design of the entire system 4) making of the prototype system for microwave heating.
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This research aims to secure fundamental data for the development offire-retardant wood by soaking dried wood in fire-retardant liquid. To dry wood, optimal drying conditions for softwood usually used as structural material and hardwood usually used as finishing or furniture material were derived by varying the microwave outputs and heating times of microwave wood drying equipment. The research foundthat each specimen needs 8 to 15 minutes of heating time depending on water content and output. For softwood, fire-retardant liquid equivalent to about 10 percent of the total mass of the specimen infiltrated into the dried wood, of which the water content was reduced to 5~6 percent.
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A Green Frame is a composite Rahmen precast concrete structure that utilizes the advantages of the steel frame and the reinforced concrete. Compared to bearing wall structure, the precast concrete structure may raise construction cost If the precast concrete members are produced in plant. Thus, if the precast concrete members can be produced in site, the cost-effectiveness and quality shall be increased. Various site conditions must be considered and reviewed to ensure a space for the in-situ production. Therefore, this study focuses on the basic study on the arrangement of in-situ production module of composite precast concrete members.
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Granulated slag from metal industries and fly ash from the combustion of coal are industrial by-products that have been widely used as mineral admixtures in normal and high strength concrete. Due to the reaction between calcium hydroxide and fly ash or slag, the hydration of concrete containing fly ash or slag is much more complex compared with that of Portland cement. In this paper, the production of calcium hydroxide in cement hydration and its consumption in the reaction of mineral admixtures is considered in order to develop a numerical model that simulates the hydration of concrete containing fly ash or slag. The heat evolution rates of fly ash- or slag-blended concrete is determined by the contribution of both cement hydration and the reaction of the mineral admixtures. Furthermore, the temperature distribution and temperature history in hardening blended concrete are evaluated based on the degree of hydration of the cement and the mineral admixtures. The proposed model is verified through experimental data on concrete with different water-to-cement ratios and mineral admixture substitution ratios.
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In this study, using the double bubble sheet to anti-freezing method in winter the soil embanking Mock up as a part of the development process was carried out. As results, two layers of the double bubble sheet effect 12.6℃~13.8℃ temperature difference of out door temperature that proved superior insulation and thermal performance of the double bubble sheet.
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Recently, an irregular-shaped super tall building has been increased, aiming toward landmarks of cityscape. However, the complex floor plan derived from an irregular shape requires considerable resources including time, cost, and effort to meet complex structural framework. Based on the motivation, the study proposes a table-form system that is variable slab form appropriate to an irregular shaped floor through improving limitations of an existing table-form system. The variable table-form is expected to reduce construction resources and improve constructability on an irregular floor plan of super tall buildings as well.
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This study is to analyse possibility cementitious powder from waste concrete as row material of recycled cement. From the results, we ascertained possibility as recycled cement through XRF & XRD of cementitious powder & recycled cement. As a result of the experiment, cementitious powder from waste concrete, which appeared to recovery hydration chemically at the calcining temperature of 700, suggested highly possibility as recycled cement.
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The purpose of this study is not only fixation of carbon dioxide using the cement-saturated solution by wet carbonating reaction but also evaluate the possibility of storage technology of Carbon dioxide. wet carbonation is reaction of CO2 injection by CO2 reactor. As a result of experiment, the carbon dioxide is fixed, and high-purity Calcium Carbonate is eluted.
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As technologies evolve, building large concrete structures ever built, but due to lack of maintenance after completion of concrete corrosion, leaks, and preparedness from the problem that is an urgent need. In particular, water-resistant variety of concrete structures. How the concept applies to the most important public drinking water purification and drinking water that is draining the production and storage, and distribution as the structure cause damage to the structure when the contaminated water is supplied to each home that can harm the health of citizens is the cause. Therefore, the correct choice of materials, and thorough a lot of investment in construction and maintenance should have. In this study, unlike conventional water-proof materials, methods, and in other reactions easily than conventional poly-urea resins have good physical performance and chemical resistance, high performance polyurea resin performance review of the physical infrastructure of the country for the longevity of would like to make long-term durability.
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According to Bali Roadmap, Korea is also included in nations with a duty to reduce greenhouse gas. This study aims to draw proper Si/Al ratio by analyzing flowing and strength properties as the 4-component low carbon inorganic composite to reduce the use of cement and discarded polysilicon sludge. As the result, when Si/Al ratio is 4, the highest strength was found.
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This study tried to utilize basic data for developing the cement substitute material through ternary system inorganic composite properties of flowing and strength. W/B and addition ratio of Na2SiO3 have been changed in ternary system inorganic composite combined blast furnace slag, red mud and fly ash. As to the experimental result inorganic composite, the flowing and intensity improvement effect was showed to be bigger than W/B according to the addition ratio change of the Na2SiO3. When particularly the Na2SiO3 addition ratio was 6%, the rapid flowing and strength improvement effect was confirmed.
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This study is to propose a curing method for a concrete wall structure under severe cold climate. The curing methods of using heated cable, heated panel and insulated form were applied. Results showed that the concrete cured by the heated cable resulted in the highest temperature history and the highest strength development at 28 days. Further, it is believed that the curing methods of the heated panel and insulated form are also recommendable for the resistance of the early frost damage on the concrete in practice.
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The facilities producing the nuclear energy chosen for resolving the recent global energy problem have been increasingly constructed, and hence more frequent durability tests on radiation shielding concrete are required due to NPP(Nuclear Power Plant) life extension and increase of radioactive waste repositories. Bulk dry density is one of the critical factors ensuring the durability and performance of the radiation shielding concrete because the design of the radiation shielding reinforced concrete structures for NPPs is based on the bulk dry density of the concrete. Bulk density of unconsolidated shielding concrete can be calculated utilizing a test assuring to satisfy the bulk dry density, or existing credible data set. This study evaluated correlation between bulk density and bulk dry density of the concrete used for Korean NPPs (y=1.0913X-0.2458) and developed a correlation expression considering standard deviation of bulk dry density (y=1.0913X-0.3358).
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This study is to investigate the engineering properties of low heat concrete incorporating improved ternary blended cement by combining OPC(original portland cement), blast furnace slag and fly ash. The results were summarized as following ; For ITB(Improved Ternary Blend)mixture was that setting time proved to be accelerated, and adiabatic temperature rises were low. The use of ITB resulted in an increase of initial compressive strength.
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In the 21th century, there ate problems of the environment caused by industrialization. for several years, the world has suffered great losses because of unforeseen weather phenomena. to make a system is needed about natural disaster especially to restore disaster on heavy snow, a role of construction temporary system is important. it needs to be construction temporary system to recover through analysing cases of disaster on heavy rain.
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Construction plans for large construction projects are problems such as Incompatibility of information, omissions due to technical limitations of 2D CAD. In addition to, Plan established for the validation such as process, cost and construction technology plan is difficult. By occurring Frequent changes in the course of business, Inefficiency of management has occurred. In the construction process, there is occurred costs and construction delays due to reconstruction or communication error. In this study, It was deemed BIM will complement Existing 2D CAD problem. And, BIM case studies in the construction phase of domestic construction were analyzed, How to apply BIM in the construction phase investigated.
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Recently, due to global warming, CO2 emissions is one of the global issues over all areas including construction industry. In Korea, apartment housing has large ratio of building construction and its CO2 emissions during the operation and maintenance has the most large amount of tatal life cycle of apartment housing. However, there are rare research related to this subject. So, this study investigates the CO2 emissions of domestic apartment housing during the operation and maintenance. In the future, the results of this study can be utilized in further study to decrease CO2 emissions strategy.
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It is necessary to the development of the best maintenance system for applying the long-term maintenance plan using the cost breakdown structure in the educational facilities. This study developed the cost breakdown structure for the best maintenance system using the delphi method. For the convenience of maintenance, the maintenance cost breakdown structures are separated into building exterior wall, building inside wall, electric installation, heating installation and outdoor facilities. And these results atomized in each parts. And this study constructed the cost breakdown structure to maintenance's practicality and effectiveness through the expert analysis.
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During the financial crisis in the late 1990s, we witnessed the large corporations failing at one moment. It is clear that the debt-dependant size augmentation and duplicate investment, and the failure in fund liquidity adjustment were the greatest causes rather than the long-term strategic advantage. Such fact, however, has led to the introduction of advanced financial techniques and security/management of fund liquidity. In order to propose a method to secure fund liquidity at the construction level, this study considers the documentational/precedent studies on project financing among fund procurement methods. And the fund liquidity status at construction level is investigated domestically/internationally to analyze the fund flow. Finally, the actual data is used to analyze progress rate and sales rate to end with the proposal of the method to secure fund liquidity in the progression of this study.
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The construction industry in Korea has seen significant improvements in quality management techniques, driven by the dramatic development of new technology through enlargements, but compared with technical development, the level of building quality improvement is still lagging behind. Therefore, in this study, a work process and system improvement plan for payment regulations is proposed, with which contractors can secure quality voluntarily in the building construction project.
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Compared to the other industries, construction industry depends many parts of production activities on manpower. And also 3D perception on construction industry and the shortage of motivation in construction workers are the biggest reason to reduce construction productivity. So to solve this problem, the research of factors which affect more to improve the construction workers attitude in construction site will be needed. This research has investigated that the productivity and important factors was divided to economic factors, social factors, psychological factors. The result show that economic factors remain pre-eminent in influencing productivity, but that social factors and psychological factors appear to be of increasing importance in this construction industry.
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This paper presents a basic study which is to develop concrete cylinder moulds for a proficiency testing compressive strength of concrete among laboratories accredited Korea Laboratory Accreditation Scheme(KOLAS). The concrete cylinder moulds sufficiently have homogeneity for a proficiency testing which is a means of assessing the ability of laboratories to competently perform specific test and measurements. The concrete compressive strength specimens placed different consolidation methods were analyzed by a statistic technique. The methods of consolidation are rodding, and internal or external vibration.
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To prevent energy waste in buildings used heat insulator. Heat insulator materials can be classified inorganic and organic. The organic material is due to toxic gas emission, when a fire occurs. And it has lower water resistance. The inorganic material is heavy and worse thermal performance than organic materials. This study focused on evaluation of the physical properties and fire-resistance of inorganic foam material for using industrial by-products materials for the applicability of Fire-resistance Light-weight material.
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This study provides floor vibration analysis for a factory constructed by ES-beam using field measured acceleration data. The natural frequencies of the first two modes of floor are extracted from measured data. With this information, a system identification has been performed to produce a numerical model representing existing floor. The peak magnitudes of acceleration for one man walking heel drop load from experiment and numerical model are analyzed using ISO vibration criteria and AIJ vibration performance criteria. The results show that there is no problem in use of ES-beam.
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The temporary support system in Korea have been carried out generally along with installing supports, which are struts, anchors, rakers. However, most of existing support systems in application relatively have limitations such as cost increase, construction configuration, and displacement occurred with support systems. Thus, a new retaining support system(referred to as the SSR, NET No.533) was developed to solve the aforementioned problems. This study introduces the design, construction, and maintenance of the SSR system under the different construction conditions. The behavior and characteristics of the SSR system were identified based on the case studies.
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Construction projects that should be under the construction supervision regulation were decreased in 2008 and new supervision projects in 2010 were significantly reduced by 60% comparing to the ones as of 2009. On the contrast, the volume of world construction projects including Middle·South Asia and Africa is forecasting to be increased by 46% in 2018. However, although the needs of oversea expansion of domestic construction supervision firms are appeared more and more, their preparations to the strategically important areas in the world are insufficient. Thus, this paper aims to suggest directions of strategics and plans for domestic construction supervision industry to expand the market to the world through questionnaire surveys and expert investigation.
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In this research, among thermoplasticity plastic raw material that recycling is possible polyolefine(TPO) and polyvinyl chloride(PVC) as target recycling plan examine wish to. It is polyolefine(TPO) and polyvinyl chloride(PVC)) is mediocrity material that there are a lot of amount useds among plastic material and it is material that recycling is also activated most. Long term made first new regulation raw material, by-product raw material happened at process of production at second factory and third time to examine recycling plan of this material divides this as raw material that pass through process separation and pelet Tuesday and analyzed each special quality removing each removed waste after is used. Measure tension strength and ext. heightening gradually mixing proportion of refreshing resources on standard Sample manufactured as new raw material and application examined possibility availability to single fly system.
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The purpose of this study is to suggest the development direction and performance analysis of design review system in design-build project. As a result of surveys, the fairness and transparency of design review system was abruptly increased. But local government has not fairness and transparency. Therefore this research has proposed the integration management and joint application of design review organization in design-build project. So, we expect that the transparency is raised in management of design review committee.
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Various desired performances of concrete cannot be always obtained by current conventional mix proportion methods for recycled aggregate concrete (RAC). This paper suggests a new design method of mix proportion for RAC to reduce the number of trial mixes using genetic algorithm (GA) which has been an optimization technique to solve the multi-object problem. In mix design method by GA, several fitness functions for the required properties of concrete, i.e., slump, strength, price, and carbonation speed coefficient were considered based on conventional data or fitness function. As a result, various optimum mix proportions for RAC that meet required performances were obtained and the risk evaluation was also conducted for selected mixtures.
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The present tests examined the resistance to freezing and thawing of alkail-activated (AA) slag concrete having compressive strength between 30~56 MPa. To enhance the compressive strength and resistance to freezing and thawing of AA slag concrete, Na ions were used for an activator. Test results revealed that the resistance to freezing and thawing of AA slag concrete is comparable to that of cement concrete when compressive strength is more than 50 MPa.
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The purpose of present study is to examine the application of effective curing to hardener-free epoxy-modified mortars. The epoxy-modified mortars are prepared with polymer-cement ratios, subjected to two types of curing conditions, and tested for compressive, flexural and tensile strengths. As a result, hardener-free epoxy-modified mortars with steam curing is markedly improved with increasing air-dry curing period. High strength development of the epoxy-modified mortars may be achieved by the dense microstructure by cement and the hardener of the epoxy resin in the mortars.
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Gypsum is an important building material used to provide fire resistance to constructions by reducing their temperature rises. As the hardened gypsum is exposed to fire, evaporation of both the free water and the chemical bond water is easier than that in the cement extruding panel. The purpose of this study is to investigate the utilizability of alpha-hemihydrate gypsum to prevent spalling failure of cement extruding panel exposed to fire. This paper reports the fire-resistance property of a controled general cement extruding panel(C100), and gypsum-cement extruding panels(C50A50, A100) according to replacement ratio of alpha-hemihydrate gypsum. As a results, it is found that A100 and C50A50 are more effective to prevent the explosive spalling failure under standard fire condition than C100.
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This study investigated about how much the limestone's volume was changed as time passed while maintaining a certain level of moisture condition in the limestone material for concrete under high temperature. The result is summarized as follows: It was appeared that the limestone material under high temperature emitted some CO2 resulting from the decarboxylation, so that as the heating temperature was increased, the limestone's length change rate was decreased. In the leave time change after heating the stone, the both conditions of 50% and 100% made the limestone create Ca(OH)2 using some H2O. So it was appeared that as time passed, the limestone's length change rate first increased because of its volume expansion, but the rate was reduced after the limestone material was crumbled.
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TNowadays, the global warming is the most serious problem in the world and the cement industry is one of the factors which are responsible for it. Therefore, the development of new binders with enhanced environment and durability performance is needed. In this regard, the geopolymer technology is one of the breakthrough developments as an alternative to the portland cement. This paper shows some points of view on the development of geopolymers by reviewing previous researches including historical background, constituents of geopolymers, process of geopolymerization and several applications of geopolymer. Hence, the author proposes two research trends which are finding the best combination between the source materials and alkali liquid then, evaluating the corrosion for the metal bars.
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South Korea is a ninth greenhouse gas emission nation in the world(2007) and is certainly to perform a duty to conduct reduction role by the Kyoto Protocol in 2013. waste concrete produced in the country is 45 million tons per year and these two issues are being came to the fore as major problems of society. However, if it utilizes wet carbonation system carbon using carbon dioxide and waste concrete as raw material it can expect effect of environmental protection and resource recycling. Furthermore, it can exploit another industry production.
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A Study on the Residual Mechanical Properties of Fiber Mixed Concrete with High Temperature and LoadRecently, the effects of high temperature and fiber content on the residual mechnical properties of high-strength concrete were experimentally investigated. In this paper, residual mechanical properties of concrete with water to cement (w/c) ratios of 55%, 42% and 32% exposed to high temperature are compared with those obtained in fiber reinforced concretes of similar characteristics with the ranging of 0,05% to 0,20% polypropylene (PP) fibers by volume of concrete, and considered factors include pre-load levels (20% and 40% of the maximum load at room temperature). Outbreak time and water contents were tested and were determined the compressive strength. In the result, it is showed that to prevent the explosive spalling of 50MPa grade concretes exposed to high temperature need more than 0.05Vol.% PP fibers. Also, the cross-sectional area of PP fiber can influence on the residual mechanical properties and the spalling tendency of fiber reinforced concrete exposed to high temperature. Especially, the external loading increases not only the residual mechanical properties of concrete but also the risk of spalling and the brittle tendency.
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Construction projects are being more complicated in proportion to the economic development. Process management is a critical issue in the construction that decides success of a project. Especially, a TACT method which divides and manages resources to repeat each activity is more important. Although becoming an issue dealing with the delay at winter season, it is not property developed. This paper suggests 'activity priority method' and 'TACT unit method' through case study. We validate necessity and efficiency of the TACT method through simulations and a survey. We expect cost reduction by decreasing unnecessary spending.
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In order to combat climate change, green building is expected to demand in the domestic market. To activate the market for domestic and international trends are examined. And Green Building Find out about the necessity and economic benefits. The following, search for the domestic and international cases. In this study, activation of the plan for the domestic market is to study.
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2009 Presidential Council on National Competitiveness to plan trying to the advancement in the construction industry 'design and engineering of the global competitiveness' in the content of weak points of the design and engineering capabilities to secure the overall problem. In domestic technological of design and engineering behind the other building construction sector about 70%. Especially hindrance factor was founded between design ordering organization, design firm and subcontractor in working design stage. In this paper carried out to hindrance factor that decrease the efficiency in working design stage for a strategy to improve the utilization of basic data.
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Non-working days owing to climatic factors have been negatively affected in productivity of construction, such as delays of project completion times, decrease productivity of construction. Especially non-working days of steel erection work is about 58 days, it is influenced deleteriously to estimating uncertain construction duration. To solve this problem, Construction Factory(CF) and sliding roof system installed CF's upper side are developed in korea recently. This study is proposed the design of sliding roof system through assess relation of requirements and technical characteristics using Quality Function Deployment(QFD). The basis data for applying QFD is collected from literature reviews and questionnaires/interviews targeting system developer, experts and researchers.
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Kim, Tae-Hoon;Lee, Ung-Kyun;Yoo, Wi-Sung;An, Sung-Hoon;Doh, Nak-ju;Cho, Hun-hee;Kang, Kyung-In 133
While researches related with construction automation have dramatically increased, a Robot-based Automatic Construction system (RCA system) has developed for high-rise buildings in Korea. At the aspect that wide adoption of the RCA system is dependent on economic efficiency comparing with a conventional method, feasibility study on the RCA system should be implemented. However, due to practical limitations, the RCA system has tested to a seven story building. Based on the test results, this study implements a cost/benefits analysis to a simulated forty story building in order to derive more reliable data on the RCA system's practicability. -
A standard of estimation is used as a basis for estimating the predetermined amount of public construction. However, they raise several points of reasonable labor to be presented to a standard of estimation. For this reason, it is difficult to make a reasonable and efficient estimation of the costs, and this situation presents an urgent need for an accurate way of making such a calculation.This study analyzed the productivity of reinforced concrete work by the CYCLONE model, and the estimated optimal labor through sensitivity analysis, and presented the model on the number of optimal labor through sensitivity analysis.
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Mainly in construction liens to four contractors do not receive your order is caused by construction. This construction does not receive construction compunction to protect the contractor, I guess. On the other hand, the medium and small construction companies and contractors that could threaten the order four can be a problem. In this study, small construction companies to the lien of the lien claim on the issue of case studies have looked for the study. Small construction companies, in your case through the litigation between the lien of the lien litigation perspective, the cause of four orders after the analysis step by step construction was listed in chronological order. Identifying problem was the result of a lien. This study to previous studies regarding the lien on the issue through case studies of one kind of lien was derived for the problem. A follow-up studies and more case studies and interviews are considered necessary in the study.
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The government encourages adoption of Rahmen structure design to ensure efficient management of national resources. However, in comparison with bearing-wall structure, Rahmen structure requires higher unit construction cost and present challenges in terms of securing adequate floor area ratio and floor height. That is why project clients have been disinterested in adoption of Rahmen structure design. Therefore, we have attempted to find factors having influence on decline of project viability for Rahmen structure. This study will be utilized as a basic reference study for promotion of Green Frame design which is a composite PC structure already developed.
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This study is a relatively small scale compared to the massive construction company, construction company's safety management level of the low. A small architectural scene safety management is a necessity for basic research as a whole and of 67.20% died in the disaster, which killed the disaster scene in a small building. Small construction site for a reflections of the prevailing security situation, the existing literature and statistical data to determine what the issue, for the purpose of the proposal and come up with improvement measures.
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Recently the construction project is intricately linked to the between participants. it is because construction informations are not integrate. This study suggests 3D modeling standard for integrated construction information. These suggestions can be useful to automation quantity take-off.
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Lifting plan in conjunction with the overall construction plan will be established. It is being created by executive director of the Corporation and other such as an experienced site manager. But, written lifting plan based on the limited information and experience is causing some problems such as decreasing productivity, workability loss, delay. The reasons for the problems are lack of prediction of construction execution, inappropriate materials on the past performance, individual experience, limits of knowledge, lack of technical materials, shortage of advisor. Therefore, to solve the problems, we have to overcome the situation in which we depends on lifting planner's experience and intuition, limited information by accumulating objective and reliable materials. Because unorganized lifting plan will lower efficiency of lifting equipment and make reducing construction period difficult. In this study, influence factors on lifting plans will be derived through reviewing literatures and lifting plan cases. Derived influence factors will be classified as components and classes, classified influence factors are assessed suitability. Also, Decision making items are derived from the factors. Finally, tower crane lifting plan process will be suggested from the result.
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This study applied BIM(Building Information Modeling) technology for Long-life Housing within exterior, interior and building equipment. There has many changes and depression infill material after construction. Therefore to understand establishment of repair and replacement cycle is necessity. In addition, the method of classification is necessary because of construction equipment efficiency. On this study, we will find how can we manage them and establish the repair and repairment cycle by applying BIM technology.
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Recently, Goverment's Energy-saving policy in Korea as 'Green Growth' is very remarkable effort. By intensive poliicies, the private is encouraged to participate in policy. Especially, it is very important in the field of architecture and we have to work for construction of law system. However, these efforts of the government buildings for energy efficiency in use stage is as mandatory system that may occur in the construction phase and the enviromental impact of greenhouse gas reductions is not affected. For this reason, Assess the amount of the energy consumption and CO2 emissioont of Government Buildings in 2010 ordered by PPS(Public Procurement Service) in the construction phase and suggest to recognize the need for legal restrictions.
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As recent construction projects aim to build higher and bigger buildings, lifting operation is getting increasingly important in construction sites. Accordingly, as tower cranes get higher and higher, disasters involving tower cranes are also on the rise. According to occupational incident statistics of the Korea Occupational Health & Safety Agency (KOHSA), most of such incidents occur in installation, dismantling and climbing phases of tower crane. Therefore, it is essential to develop preventative measures to secure safety of tower crane operations, with critical focus on installation, dismantling and climbing of tower crane. Hence, this research attempts to measure criticality of key risk factors in installation, dismantling and climbing phases of tower crane on construction site and propose necessary safety measures. As a result, conclusions herein will contribute to minimize disasters and incidents involving tower cranes in high-rise building construction sites.
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In Korea, the apartment supplier should satisfy the apartment residents' demand on the defect repair found in apartment housing by the law of Management of Apartment Complexs. But in the cost of defect repair, not only the actual defect repair cost, but also the cost of residents' complains are contained. So in this analytic study, the actual use state of defect deposite during 4~10 years after moving in are analysed base on actual data of 15 apartment complexes. In this study, about 66% of defect repair deposites are used to actual defect repair and only 34% of defect repair cost are spent to satisfy the demand of apartment residents'.
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The monitoring to crack damages is studied using the radio frequency system and static displacement sensors. If load is received on the center of the flexible specimen, bonded sensors will be destroyed, and these are become to send signals of damages at the radio frequency system connected with sensors. This study is fundamental research of the monitoring damage system for diagnostic concrete elements using the radio frequency system and static displacement sensors.
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Recently there are many efforts for saving energy in building. therefore Building energy management systems(BEMS) are expected to a reduction energy cost. BEMS has many benefits which could switch plant on and off automatically. Also It optimize plan operation and services, monitor plant status and environmental conditions and to provide energy analysis and management information. In these days, many public buildings are applied BEMS but there are few studies about application of small or medium buildings. Therefore, in this study, we will find how to apply BEMS in small or medium buildings.
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Due to various kind of waterproof materials and methods, which is difficult to select the most appropriate to waterworks. The materials used to prevent the deterioration of the service life is short, because of the chemical erosion. So, in the 2010 Office of Waterworks Seoul Metropolitan Government has set new standards. Recently, SMC panel is a trend that is being applied to water treatment facilities. However, SMC panel has not yet implemented a performance evaluation. Therefore, this study to confirm that satisfaction for the Office of Waterworks Seoul Metropolitan Government of the performance requirements, when the applied the SMC panel to water treatment structure.
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This study is to evaluate the feasibility of the mix design for exposed concrete. Mock-up sized specimens were prepared, and a flowing concrete method was selected for placement. Results showed that the fluidity and air content of fresh concrete achieved target values, the compressive strength at 7 days was 27 MPa, and surface roughness was in the range of between around 1.53 and 1.68 ㎛, which was in the quality level. Therefore it is concluded that the proposed mix design for exposed concrete can be applied in practice.
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In the connection of green frame, the bottom rebar of the precast concrete beam needs joint or anchorage to ensure structural integrity. However, given the characteristics of composite precast concrete joint, enough length over which rebar can be anchored or lap-spliced is not secured. In addition, due to issues with constructability, cost or quality, it is difficult to apply welding or mechanical connection techniques. Therefore, this study analyze the requirement for a bolt-type rebar coupler as a solution for the coupling issue between the lower rebars of green frame beam. The requirement for bolt-type rebar coupler proposed herein will provide basic data for development studies of the rebar coupler.
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Green column and green beam, key structural members of green frame, have the characteristics of post-lintel structure, thanks to the steel frame in the connection, enabling prompt and precise installation. The connection of green frame can be divided into 4 types, depending on its shape, and each type is associated with different characteristics and construction methods. Notably, as the connection between green columns have differing types and sequences of work, subject to the connection method in use, a connection method optimized for relevant site conditions need to be selected. Therefore, this study analyzed pros and cons of 4 different types of green frame connection methods. The results set forth herein will provide basic data for subsequent studies to comparatively analyze the performance and constructibility of different green frame connection methods.
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Applying previous studies performed in the moisture transportation characteristics and shrinkage of lightweight concrete application of shrinkage reduction is to discuss. Applicability of shrinkage reduction effect of lightweight concrete applies for the analysis of PSC girder bridge beam placed on the construction site. Stress of the concrete bridge deck, rebar quantity is calculated by effective elastic modulus method and crack risk is assessed by moisture transport and differential shrinkage analysis. After approximately 10 days maximum tensile stress occurs 6MPa, similar to the case of normal concrete, a maximum tensile stress occurs 3MPa in lightweight concrete and comparing to normal concrete stress was reduced to approximately 50%. Normal and lightweight concrete crack index, respectively, is reduced 1.6 to 1.2, 1.2 to 0.9 in surface and boundary region. Therefore, reduction in shrinkage of concrete were able to confirm reduction of crack risk.
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The difference the guide specifications of between housing and land development has been caused many problems, since Korea Land Corporation and Korea Housing Corporation were merged into LH (Land and Housing Corporation) in 2009. Those are that specification criteria to establishing lower level specifications are disordered; duplicated investment on sites; management systems are conflicted site to site, which are based on different operation system from old land and housing corporations, etc. Thus, this paper aims to suggest a direction of integrated guide specification system of LH including improved and advanced classification hierarchy and specification.
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This study was carried out about construction management plan to reduce water leakage of underground parking lot in the apartment housing. To minimize effect of upper working load, installation position of jack support and paving with rubble on the top of underground parking lot were studied. By calculation shrinkage strain of underground parking lot scale, water leakage risk in design of level difference was studied. In this study, the basic data about construction management was provided to reduce water leakage of underground parking lot in the apartment housing.
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The purpose of this study is to develop and apply the oversea construction competitiveness evaluation model which measures the competitiveness of construction companies in global construction market. This model consists of the design and construction competitiveness indexes by ENR statistic data and provides the oversea construction competitiveness index based on the evaluation model.
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The purpose of this study is to suggest the development direction for vendor management in plant construction. Therefore this research has proposed the integration management of vendor and information standardization. This research has proposed that plant industry association manage the basic information of vendor. And each company manage the performance evaluation of vendor's firm. Expecially, vendor management system should be developed by ISO information system.
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The government has performed various countermeasures and policies for the efficiency of Construction Industry. However the analysis of the policy performance is not satisfied. In the study we benchmarked the construction performance evaluation system and indicators which was performed by advanced countries like the United States and the United Kingdom. So we suggested indicators for measuring performance of public construction cost saving strategy performed in 2008 by the Ministry of Land, Transport and Maritime Affairs. This paper will provide the basis for establishing future construction policies or plans.
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Recently, the number of high-rise buildings has been on the rise, which has meant that maintenance cost has increased by two and three times, along with the increase in the construction cost. It is suggested that the use of an auto-cleaning robot could increase the productivity and safety of cleaning work, which is mostly done outside of a building. In particular, the guide rail on a high-rise building could be useful in this capacity, as it has the advantage of not being significantly influenced by factors of the external environment, including wind pressure. For this reason, this research is preliminary research into a cleaning automation for a high-rise building, and aims to draw up a scenario for the vertically moving robot.
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Most of buildings' exterior walls are curtain wall systems and in the respect, the cleaning robot system is the main research item for cleaning and maintenance of them. We have structurely analysed the cases to review on the structural stability of the mullion members where the cleaning robot is attached. The result is showing that the largest stress is formed by the basic wind speed, which is specified in Korean Building Code-Structural.
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Absorption of lightweight aggregate affects the properties of fresh and hardened concrete, so care must be taken. In this study, according to KS F 2533 absorption is measured to aggregate size, submerged time, holding time and practically ways to maintain a constant absorption was to seek. The findings for quality control of the lightweight aggregate concrete mixture is saturation of the surface-dry aggregate humidity 100% after 24 hours immersion in the environment has been stored for more than two days to absorb the state was able to define. Dry density at the surface of the lightweight aggregate and lightweight concrete mix design and placement is possible for it to apply.
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The purpose of this study was to develop and evaluate of fire resistive cladding systems for HSC(high-strength concrete) column, which was mainly constructed with aerogel blanket insulation material. The aerogel blanket-fire protective gypsum board cladding system showed that it clearly secure the fire resistance performance of HSC column when the reinforcing measures had achieved for four cross-sectional edge sides of structure and the system is well continued during the test period with no significant deformation or separation etc. It was checked out the 20mm thickness cladding system consist with AG(5mm)+FGB(15mm) can secure 3hour-fire resistance performance adequately.
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이노가닉 폴리머 콘크리트는 비소성 알카리 활성화 콘크리트의 일종으로 여러 가지 우수한 성능을 가지고 있으며, 그 중에서도 고온에서의 열적특성이 우수한 것으로 알려져 있다. 이에 따라, 이노가닉 폴리머 콘크리트를 이용한 경량패널을 제조하여, 소형가열로 내화시험을 측정한 결과 3시간 가열후 이면상승온도가 평균 82℃ 이하로 확인되어 공동주택의 내화벽체로 활용이 가능할 것으로 판단된다.
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This study is aimed to draw a optimum combined fiber mix condition to improve spalling resistance and flowability of ultra high-strength concrete. As a result, W/B 12.5% concrete specimens were prevented spalling with PE0.05+ PP0.1, PE0.05+NY0.1 and W/B 12.5% concrete specimens were prevented spalling with all of combined organic fiber mix condition. But There is no significant influence of steel fiber under 5% volume ratios to prevent spalling. In the scope of this study, we suggest that condition of optimum volume ratio PE0.05+NY0.1 is to improve spalling resistance, flowability and residual compressive strength.
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It was very important to evaluate concrete experimentally at elevated temperature because concrete was filled with aggregate of concrete volume about 70 percent. Concrete exposure to high temperatures produces changes in its internal structure, for instance loss of its strength and deformation capacity, in extreme cases risking the service life of the structure. The work of this paper is performed to evaluate the thermal behavior of ultra-high strength concrete having different water to cement ratio (strength), fine aggregate to aggregate ratio and maximum size of coarse aggregate. For exposure to 500℃ during 1 hour, residual mechanical properties of the ultra-high strength concrete decreased as the s/a ratio decreases and the maximum size of coarse aggregate increases.
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This study investigates the fundamental properties of bast furnace-based mortar made with recycled fine aggregate. Results showed that increasing recycled fine aggregate accelerated setting time, proportionally increased the compressive and flexural strength of mortar specimens. However, it is concluded that for quality and cost effectiveness, the optimum content of this recycled fine aggregate in mortar was found to be 80%.
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This study investigates the effect of partial replacement with cement on the properties of blast furnace slag-based mortar. Recycled fine aggregate with various contents was used to activate the hydration of blast furnace slag in the mortar and compared its effect on strength development. Results showed that increasing cement and recycled fine aggregate increased the strength of mortar specimens. However, this study found that the mortar made with partial replacement of river sand with recycled fine aggregate of 20% developed a similar strength to the strength that cement with 10% can achieved.
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The advantages of blast-furnace slag concrete may include lower hydration heating velocity, restraint on concrete temperature increase, long-age strength improvement due to latent hydraulic reaction, improved water tightness, and repulsion to chemical erosion. These advantages contribute to the high quality of the blast-furnace slag concrete. However, the blast-furnace slag concrete has its limitations as well. These disadvantages may include retarded setting and elongated retention of mold due to the weak strength of early-age. Nevertheless, much research is currently under way to improve the aforementioned issues. To improve activity of blast furnace slag powder, alkaline irritants has been used. In this study, we analyze effect on activity fineness and rate of substitution of Alkali Activator toward activity.
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The research is for building safety by using fiber reinforced concrete against impact load. The aim of this study is to evaluation of Impact Resistance of mortar by Reinforcement Condition of Aramid Fiber(fiber length, fiber surface treatment, fiber contents, hyrid reinforcement with steel fiber). Thus, the results indicate that it can improve mix condition and impact resistance by fiber surface treatment.
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In this study, in order to comprehend performance of corrosion inhibitor, the experiment study was conducted about corrosion characteristic of 3 steps(0.0, norm 1/2, norm) compared to organic corrosion inhibitor standard use of liquid and molar 3 steps(0.0, 0.3, 0.6%) of Chloride by added amount of inorganic corrosion inhibitor by the corrosion inhibitor types about 2.4kg/㎥, 4.8kg/㎥ based on Chloride ion content 1.2kg/㎥ for service life prediction of concrete structure by using Poteniostat.
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This study investigates the effect of crushed fine aggregate and chemical admixture (durability improvement agent, named DIA) on blast furnace slag-based brick. The control brick was made with recycled fine aggregate of 100% and, no cement was used. Test results showed that all specimens developed similar strength, except for the specimen without partial replacement of crushed fine aggregate at 3 days. However, it is interesting to note that this specimen without crushed fine aggregate resulted in the highest strength at 7 days. In addition, the DIA had a major effect on the absorption ratio of brick specimens. For the brick specimens with partial replacement of crushed fine aggregate with 10%, the addition of DIA with only 1% was enough to satisfy the code regulated by KS F 4004.
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We could see that, the thinner the retaining wall is, the more advantageous Premixed Agent Type Waterproof method is in the aspect of economic efficiency. The reason is because, in the case of Premixed Agent Type Waterproof method, the thicker the retaining wall is, the higher the construction cost increases due to increase in the material quantity required which increases in proportion to the area in the case of Premixed Agent Type Waterproof method. We could see that, the thinner the retaining wall is, the more inferior the economic efficiency of Infiltration Type Waterproof method is to that of Premixed Agent Type Waterproof method, as, in the case of Infiltration Type Waterproof method, the quantity of material required is fixed in proportion to the area. Consequently, we concluded that Premixed Agent Type Waterproof method is economically advantageous up to the wall thickness of 700 mm and Infiltration Type Waterproof from 800 mm.
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Carbon dioxide in atmosphere causes concrete carbonation which is the phenomenon, that is, the pH of concrete changes from 12-13 to 8.85-10. Even though the carbon dioxide concentration of indoor is higher than that of outdoor, the micro measurement has not carried out. The concentration of carbon dioxide was measured in three places. The data was used as boundary condition to FEM analysis for expectation of concrete carbonation depth. The affect of building finish materials to concrete carbonation was discussed.
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This study analyzed flowing and strength properties of mortar depending to fine aggregate types and replacement ratio by using blast furnace slag, red mud, and silica fume that are industrial by products. The findings showed that higher replacement level of fine aggregate increased air content while decreased table flow. In addition, compressive strength showed that the higher replacement level was regardless of fine aggregate types, the lower strength became. Mortar substituted by the dredged sand showed high strength.
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This study was performed to investigate the influence of curing temperature on the properties of light weight foamed concrete, manufactured on-site construction according to the various experimental factor such as temperature of material, curing temperature in air(5, 10, 20℃), curing time in air(5, 10, 15hour), and target density of hardened state(0.8, 1.2t/㎥). As a result, the influence of the curing temperature on various properties of foamed concrete is greater than curing time. When increasing temperature and time in air curing, progress of hydration is fast and compressive strength is increasing more and more. However, when considering the productivity, minimum curing time is required 15hours at 5℃, 10hours at 10℃, and 5hours at 20℃. If this condition is not required, there is some crack due to volume expansion on the surface of light weight foamed concrete.
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The purpose of this study is for leaving the technical record of cultural heritage as analysis of material property mainly the structure steel used in modern domestic bridge. Result of this study, Structural Steel used in Modern Bridge Structures indicates different figuration and property with the times.
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In general, magnetite or barite (density: more than 4.0ton/㎥) has been used in concrete for radiation shielding, and radiation tests have been performed to evaluate shielding performance. However, researchers have not studied concrete for radiation shielding that utilizes electric arc furnace oxidizing slag. This research aims to utilize electric arc furnace oxidizing slag which depends on reclamation as environment-friendly concrete materials by using coarse and fine aggregates of electric arc furnace slag containing 30% ferrous metal and with a density of around 3.0~3.8 ton/㎥. Accordingly, this research has judged that the high density electric arc furnace oxidizing slag aggregate can be applied to radiation shielding concrete. It has also examined the possibility of developing radiation shielding concrete utilizing electric arc furnace oxidizing slag aggregate by comparing concrete utilizing all fine and coarse aggregate of electric arc furnace oxidizing slag with concrete using magnetite.
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In recent research in this emerging and latent heat storage material features an innovative temperature - controlled Phase Change Materials to evaluate the superior thermal performance would like to calculate the thermal conductivity. Specified in KS F 4040 test specimen dimensions were equivalent in specifications, test methods according to KS L 9016 was an experiment in progress. As a result, the thermal conductivity of plain cement mortar mixed with more PCM came out with low thermal conductivity of mortar, thermal performance was excellent.
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Pre-foaming, one of the manufacturing way of foamed concrete, is influenced by foaming agent. When the foaming agent diluted with water, surface tension and viscosity are varied. Therefore, this study is reviewing the surface tension, viscosity and unit weight of foam by experimental factor such as foaming agent types(AES, AOS, VS FP) and foam agent dilution concentration (1, 3, 5%) and temperature of materials (5, 10, 20℃). As an expeimental result, the surface tension and viscosity slightly increased with increasing concentrations. Meanwhile, when increasing temperature, the viscosity has decreased. FP produce relatively stable foams only in case 3% or more, which produce unstable foams containing large amount of water content by decreasing only insignificant surface tension when diluted at concentration of 1%.
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This study is to investigate experimentally the strength properties of mortar using recycled fine aggregates(RA) and blast furnace slag powder(BS) without cement according to type of fine aggregate. In the results of the study, compressive strength of RA was the highest. It can be considered that the results are due to the reaction of the non-hydration cement in RA to the latent hydraulicity reaction of the BS.
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The purpose of this study is to investigate chloride ion adsoption property of cement mortar using nitrite type hydrocalumite(calumite) with self-corrosion inhibition function. Superior corrosion inhibition function of the VA/E/MMA-modified mortars with calumite was ascertained from accelerated corrosion test in the previous study. In this study, VA/E/MMA-modified mortars with calumite were prepared with calumite contents of 0, 5, 10% and polymer-binder ratio of 0, 10%, and tested for chloride ion adsorption to make it clear how calumite gives self-corrosion inhibition function to cement mortar. As a result, chloride ion adsorption property of VA/E/MMA-modified mortars with calumite was improved by increasing calumite contents compared to unmodified mortar regardless of using VA/E/MMA terpolymer powder or not.
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This study investigates the effect of a curing condition on the temperature history and strength development of concrete under -10℃. Combination of various curing methods was applied, i.e. a conventional form was combined with compressed insulation, heat panel and heat cable. Results showed that the concrete cured by a single use of a conventional form resulted in serious deterioration of early strength development. However, other concretes cured by the proposed curing methods maintained the temperature of the concretes between 5 and 20℃, and thus resulted in no frost damage.