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
2018.11a
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The water proofing sheet of synthetic polymer applies to the purification plant, the wastewater treatment center, the low waterway, the dosing tanks, etc, and when we construct these, we apply the dual waterproof by means of hot air staking welder or extruder. However, the experts skilled in the hot air welding or extruder does not use them, it can be a quality problem. Therefore, in this study, it is the purpose to verify whether the semi-automatic hot air staking welder and automatic extruder that can construct the waterproof sheet is possible in field even if it is not a professional specialist.
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In the previous study, durometer, namely rubber hardness tester Was used to confirm the possibility of using the setting time of concrete for determination. in this study, the possibility of using condensation time judgment condensation estimation system by comparing the measuring station setting estimation system Measuring needle of the proctor penetration resistance tester by newly making a measurement needle and refining the coagulation estimation system Want to make sure. As a result of this study, it was possible to use one condensation estimation system showing similar correlation between the two types of durometer showing high correlation with the penetration resistance value of proctor testers, It is considered to be fruitful to use the dew condensation estimation system for determining the setting time.
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3D printing has the unique advantage of the ability to customize freeform product even in small quantity. However, we need to select and apply the only necessary parts of it because of the high cost of the manufacturing technology. It is of critical importance in irregular-shaped curtain walls to ensure precision of construction as well as quality fo finish. Complex shape that have structural members at varying angles can have nodes of different shapes making it unfeasible to construct using a general node connection detail. Therefore, this study aims to utilize smart node system using 3D printing as a solution to complex irregular-shaped curtain wall design.
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Internal Insulation system is applied to the most apartment building in Korea. However due to the importance of building energy enhanced the interest of the exernal insulation system. The extermal insulation system has better thermal performance because the thermal bridge through the structure are rarely formed. But the thermal bridge around the window decrease the thermal performance of the envelope system. Therefore the technology for reducing the thermal bridge around window improves energy efficiency of the building. In order to this it is necessary to minimize the thermal bridge around window of building. In this study it is aimed to minimize the thermal bridge around the window of building. It was confirmed that the use of thermal bridge barrier imporved the heat transfer rate by 64% or more and the condensation reduction phenomenon by 42% or more compared with the exist technology. These thermal bridge barrier will be used as the main technology to improve the energy efficiency of building.
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Reinforced concrete works account for 40 to 50 percent of the total construction work. However, the shortage of construction workers is a problem in the delay of the construction period of reinforced concrete. The partial rebar prefabrication is one of the ways to shorten construction period. Thus, this study compared the partial rebar prefabrication and field fabrication method through work sampling. As a result, the partial rebar prefabrication showed a significant decrease in time compared to field fabrication method. As a result of this study, it is expected to be used as a reference for the efficient selection of reinforced concrete methods.
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Logistics facilities are characterized by wide spans and high flooring, most of which are constructed with PC (Precast Concrete) methods to meet a wide range of commercial and industrial needs. However, the PC structure is a pin joint design, and the construction cost is increased due to the restrictions caused by the installation process, and the construction period is lengthened. In order to solve the above problem, SMART Frame, which is a structural system similar to the steel frame structure, was developed by embedding a steel frame at both ends of the PC. The purpose of this study is to analyze the erection time reduction effect of steel connected precast concrete components (SMART frames) for long span and heavy loaded logistics buildings compared to existing PC frames. For this study, a logistics building constructed with pin joint PC components is selected as a case. The result is compared with the existing PC frame to confirm the erection time reduction effect.
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A few years ago, the rapid degradation of domestic air quality has led to the efforts of exhaust gas policy and fine dust mask, but it is not a fundamental measure. In Korea, photocatalyst will be applied to residential and multi-use facilites to purify indoor and outdoor air. Also, in this study, it is tried to produce exposed concrete that is aesthetically pleasing as well as air purification of indoor by combining with light transparent concrete according to the increasing interest in human indoor living environment. For this purpose, we have developed a block formwork for photocatalysis light transparent concrete and established a suitable manufacturing method for on-site construction.
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As energy related problems continue to arise, Korea's thermal insulation market for the zero energy homes is also demanding major changes, but there are no realistic countermeasures. Also, interest in inorganic insulation is growing as damage from multifamily housing fire using flammable insulation materials is increasing. On the other hand, many studies have been conducted on lightweight foam concrete, which implies a sufficient possibility as an insulation material by generating a large amount of air bubbles. However, studies of existion bubble concrete are not quantified by the experimental difficulty of using bubbles when compared. Therefore, in this study, the change in strength due to air pressure using a bubble foam, one of the types of air bubbles for the development of light foam concrete.
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In this study, the characteristics of the Mock-up test were reviewed to analyze the applicability of the coal gasification slag (CGS) from the integrated gasification combination Cycle (IGCC) to the concrete fine aggregate. The analysis shows that CGS and crushed sand mix is the best combination of CGS combined with about 50 % 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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Reinforced concrete is a building material that is generally used in modern society. Also, reinforced concrete structures in high salinity environments have low durability due to corrosion of reinforcing bars due to infiltrated chlorine ions. Anion exchange resins have an ability to immobilize chlorine ions in the resin while releasing their anions. As a material, it has already been shown that it is possible to fix the chloride ion inside the cementitious material through the cement mortar experiment. The purpose of this study is to confirm the compressive strength of cement mortar using powdered anion exchange resin after powdering an anion exchange resin. In order to confirm the chloride ion fixation ability of the powder anion exchange resin, chlorine ion penetration resistance test was carried out.
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Various concrete material technologies and new materials have been developed in accordance with the advancement of buildings. As part of these new technologies, light transparent concrete, which was invented by Hungarian architect Aron Losonczi and attracted worldwide attention, has a technique of arranging optical fiber inside concrete and transmitting the light from exterior to concrete to show silhouette inside. However, due to many disadvantages, application to the field was limited and commercialization was not easy. In Korea, Light Emotion Friendly Concrete has been developed for commercialization. In order to solve the degradation of construction performance caused by the arrangement of expensive optical fiber, which is pointed out as a disadvantage of translucent concrete, It converts expensive fiber into low cost acrylic rod, easy to arrange, pre-assembled to form and post-cast. Therefore, this study aims to improve the mechanical properties of LEFC and to derive optimal combination.
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In this study, water vapor pressure and restrained stress were evaluated by ring-type restrained condition for compressive strength 60 and 80MPa concrete. Experimental results show that the 80MPa concrete has higher water vapor pressure and restraint stress than the 60MPa concrete, resulting in spalling occurrence. It is because, the higher the compressive strength of the concrete, the more dense the internal structure is formed.
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The development of the industry has increased the indoor living time of modern people. Therefore, indoor pollution is attracting attention as a social issue. One of the indoor air pollution is formaldehyde. Formaldehyde has been classified as a first-level carcinogen by international cancer research organizations. Formaldehyde has been used to protect products such as construction materials and finish materials, and being diffused in the interior construction process. In this study, we used phytoncide with cement matrix to reduce formaldehyde, an indoor environmental contaminant. The strengths was increased slightly and formaldehyde showed a reduction effect over time.
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Lately, cement mixed siliceous powder waterproofing coating has been used as a waterproofing material in the wet environment condition of an underground concrete structure. Underground is exposed to environmental influences such as pressure of ground water, pressure of soil. However, the quality standard for pressure (water pressure, earth pressure) is not specified in the specification of the cement mixed siliceous powder waterproofing coating. Therefore, in this study, the permeability test was carried out based on the assumption that the durability should be verified in consideration of the environmental aspects of the material in actual field. As a result of the test, the permeability was generated from the inorganic single type material, but it was caused by the sealing failure and the test error, and the permeability was not generated in most of the materials. The results of this study will be analyzed by reviewing the physical properties of the material, and the research direction will be resumed.
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As a result of measuring the compressive strength and semi-adiabatic temperature rise of the mixed mortar, it was confirmed that the mortar mixed with the hydration heat reducing material is effective. On the other hand, the compressive strength showed similar strength to that of moderate heat Portland cement until the age 7 days, but after that, the tendency of the strength development to be delayed was confirmed.
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Korea has many problems due to the asphalt pavement or impermeable pavement. Many methods are being implemented to improve water circulation. Among them, permeable packaging materials are used. However, existing permeable packaging materials have a problem of causing efflorescence and clogging the pores. The pores of the permeable packing material are clogged and the permeability is lost. This leads to economic problems and product problems. The purpose of this study was to develop a block to prevent efflorescence.
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Foame concrete was used to reduce insulation problems and interlayer noise in slab. There have been no studies on the physical properties of foaming agents using foamed concrete,Only the physical properties of foamed concrete mixed with foam agent. It is judged that the density and distribution of Foams will be changed when the pressre is changed when the bubble is formed. In this study to investigate the changes of Foam density and the physical performance of foamed concrete by changing the pressure during Foam formation.
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The purpose of this study is to compare the amount of critical chloride of rebar embedded in concrete according to the substitution rate of admixture. In order to determine the starting point of corrosion of rebar, electrodes were embedded in concrete, chloride was supplied, and OCP of rebar was observed in real time. The amount of the contaminants in the concrete surrounding the rebar was judged to be the critical corrosion chloride contents of the rebar at the start of the corrosion. As a result of the comparative evaluation, it was confirmed that the critical chloride contents of the rebar decreased with increasing the substitution ratio of the admixture.
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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 20% of blast furnace slag replaced concrete. As a result, for 28 days of managing period, 9, 6, and 3MPa of compensating strength values were suggested when the temperatures were from 4 to 6℃, from 6 to 12℃, from 12 to 17℃, respectively. Additionally, for 42 days of managing period, 6 and 3MPa of compensating strength value was suggested when the temperature was from 4 to 7℃, from 7 to 12℃, and for 56 days of managing period, 3MPa of compensating strength value was suggested when the temperature was from 4 to 9℃. Furthermore, for 28, 42, 56, and 91 days of managing periods, any compensating strength values were needed when the temperature were higher than 17, 12, 9, and 4℃, respectively.
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In this study, water vapor pressure of high strength concrete reinforced with amorphous steel fiber(AF) was evaluated. Experimental results show that spalling occurs when the incorporation rate of amorphous steel fiber is 0.5 vol.% or more. This is because the ratio of AF increased per unit area influenced the formation of the water vapor pressure discharge passage by the polypropylene fiber(PPF) melting. Therefore, it is necessary to find the proper mixing ratio of AF and PPF to prevent spalling.
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High performance concrete with low water-to-cement ratio has been widely used with increased demand of high rising buildings and huge scaled structures. Additionally, for high performance concrete, various SCMs are replaced to improve its performance from fresh state to hardened state. With the drawback of increased viscosity of the concrete mixture for high performance concrete, low-viscosity typed high range water reducer is the relatively new admixture. Therefore, as a goal of the research, under using various SCMs with wide range of content, the performance of low-viscosity typed high range water reducer was evaluated. Especially, in this research, the influence of low-viscosity typed high range water reducer on rheological properties including plastic viscosity and yield stress were assessed. As a result of the research, it is expected to provide a fundamental information of low -viscosity typed high ranged water reducer on high performance concrete with various conditions of SCMs.
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Recently the old buildings have been increasing and increasing reconstruction. As a result, the frequency of use of architectural adhesives has increased. Adhesives are not only used for bonding but also for building materials used in various fields. However, since the adhesive is made of an organic material, it causes various skin diseases and sick house syndrome, and when a fire occurs, harmful substances are generated, and incomplete combustion may cause personal injury. Therefore, in this study, to solve the disadvantages of conventional adhesives, we tried to develop inorganic adhesives using inorganic materials.
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Although the introduction of new materials and new construction methods and overseas materials has become more active due to the diversification of the construction market, the quality standards of waterproofing methods in Korea are insufficient. In particular, the quality control standard is applied to the KS F 2622:08 (Membrane Waterproofing layer performance test method), which is the existing standard, to prepare standards for quality control of waterproof materials, which is increased in Korea.
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As a result of exposing the concrete at 1 and 6 atm in order to evaluate the salt resistance of the pressurized marine concrete, the pressure resulted in promoting the chloride ion penetration of the concrete. Particularly, the amount of water soluble chloride in the surface area tends to increase rapidly, and this cause is considered to be highly correlated with the size of the capillary pores of the concrete. On the other hand, the blending of blast furnace slag was effective to increse chloride attack resistibility even under the pressure.
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In order to reduce the risk of accidents, we proposed a construction safety management system combined with wearable device and LoRa (Low-Range Wireless Network) communication method to apply the usefulness of Internet (IoT) technology which means "everything connected". to construction safety management Management system. The proposed wearable safety device is a device that relays information exchange between wearable safety device and safety management server by LoRa wireless communication method. The safety management server can store workers bio-data and perform big data analysis. If a risk factor is determined from the analysis result, a warning is sent to the wearable safety device and the manager's application. The goal of this system is to prevent construction workers from entering the dangerous area that is not suitable for work, and to prevent safety accidents caused by human cause by detecting abnormal condition during work.
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The number of deaths in the korean construction industry is more than three times the OECD average. Although safety management system should be improved to prevent the safety accidents, it is difficult to improve due to domestic safety conditions. Especially, in order to prevent accidents at construction sites, there is an increasing tendency to monitor the movement of workers and equipment in real time by introducing a location positioning system. Therefore, this study proposes a system that can monitor the position of workers and heavy equipments in real - time, detect danger and transmit alarms so that workers can pay attention to safety and keep safety. The system is expected to reduce safety accidents by transmitting alarms to workers so that they can pay attention.
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The purpose of this study is to predict and classify the accident types based on the KOSHA (Korea Occupational Safety & Health Agency) and weather data. We also have an effort to suggest an important management method according to accident types by deriving feature importance. We designed two models based on accident data and weather data (model(a)) and only weather data (model(b)). As a result of random forest method, the model(b) showed a lack of accuracy in prediction. However, the model(a) presented more accurate prediction results than the model(b). Thus we presented safety management plan based on the results. In the future, this study will continue to carry out real time prediction to occurrence types to prevent safety accidents by supplementing the real time accident data and weather data.
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On this Study, it conducts the Standards investigation about air leakage of Buildings for performance improvement of Smoke control in Fire. In domestic standards, it is incomplete the Criteria standards of air leakage. Therefore it is considered that won't limit the smoke spread due to stack effect. But in the case of the United States, it conducts the Hot smoke air-Leakage test and it consider that can prevent the Smoke Spread in Compartment.
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The construction industry is one of the most prolific disaster-prone industries, particularly those that suffer from falling disasters compared to other industries. The safety accident at the construction site leads to social problems caused by massive loss of life and property, so it needs to be extra careful. The reason why falls are the most frequent accidents of the types of construction accidents is due to the analysis of the risk factors of safety accidents and the development of various construction methods. Therefore, in this study, the accident case for the fallen victims of construction site was analyzed and the risk factor was selected. Based on the safety expert survey, an importance analysis was performed. In conclusion, this study analyzes various risk factors that affect the occurrence of falls, identifies the importance of each factor, and presents basic data for safety accident prevention activities.
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As a result of this study, it was possible to derive the compressive strength curves of ordinary to ultra high strength concrete using the hammer type non - destructive testing equipment. In order to obtain reliable results, it is necessary to construct additional data. In addition, if reliability is ensured through construction site evaluation, it is considered that the application is possible on construction site.
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In the public sector, the number of interior construction projects is continuously increasing. When the interior construction is carried out, it is largely divided into design and construction stages. On the other hand, in order to place an order in the public sector, it requires institutional conditions such as business type, price criterion, award criteria, and guarantees. But in th case of interior design, it is necessary to establish a basis law to be applied for ordering. Therefore, this study analysed the necessity of improving the system related to the interior design order in the public sector and suggested ways to improve the system. In the future, we will continue to conduct research based on this research, and if institutional improvement is made through the proposed methodology, it will be possible to apply effectively not only in the public sector but also in the private sector.
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With increased interest in the Fourth Industrial Revolution, there is also a growing interest in the innovation of college education. In this regard, this study aims to develop a learning model for building construction to nurture architectural engineers needed in the era of the Fourth Industrial Revolution. To this end, it analyzed the previous studies on the recent innovations in engineering education. Among the educational innovation methods presented in the previous research, a new learning model was derived by using the most suitable method for the building construction eduction. The derived learning model is a building construction learning model applying team-based learning and flipped learning. The learning model proposed in this study was developed as a learning method to nurture engineers needed in the future. Therefore, it is expected that this model can be utilized in the eduction of architectural engineering at universities in Korea.
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In this study, it evaluate the tensile properties of polyamide fiber reinforced cementitious composite and hooked steel fiber reinforced cementitious Composites by strain rate. Polyamide fiber reinforced cement composites (PAFRCC) and Hooked Steel Fiber Reinforced Cement Composite(HSFRCC) were fabricated. Each specimen was reinforced with 1.0 and 2.0vol% fiber. The length of the reinforced fiber was 30 mm for both fibers, and the tensile test specimen was made in dumbbell shape. As a result, the tensile strength of fiber in polyamide fiber and the mechanical bonding between fiber and matrix in hooked steel fiber are considered to be the main factors affecting tensile behavior of fiber reinforced cement composite.
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MiDF, Micro Defect Free concrete, is the concrete made for high strength development by minimizing the defects such as micro pore and ITZ. Since MiDF exhibits strength through hydro-thermal synthesis reaction, it is essential to select the optimum C/S mole ratio. In this study, the basic characteristics of MiDF were evaluated by controlling the C/S mole ratio by SF and QP.
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Form-work is a must for construction work. In order to secure the best condition of the form surface and to increase the number of times, the form releasing agent is applied during the process of the form-work. The base oil of the form release agent which has been used already uses the oil which directly or indirectly affects the natural environment and the concrete. In this study, the basic study on the form release agent for concrete was carried out only for the effect of adhesion. The adhesive force of the tile is measured by the mortar to determine the change of the releasing agent and the adhesive strength.
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Recently, the interest in remodeling of new and old buildings is increasing worldwide. As a result, the frequency of use of architectural adhesives has increased. Currently, adhesives used in buildings are made of organic materials in most cases, and epoxy resin adhesives are most widely used. However, epoxy resin adhesives contain formaldehyde and VOCs in the room during construction, which can cause sick house syndrome. In case of building fire, it may cause damage due to carbon monoxide generated from organic materials. It is urgent to study the problem of epoxy fill adhesive made of such organic materials. Therefore, the purpose of this study is to investigate the effect of the adhesion of epoxy resin adhesive, which is a problem of epoxy resin adhesive, which is an existing organic adhesive by using inorganic materials such as magnesia and phosphate, And the inorganic adhesive which does not emit the release amount as an inorganic material.
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The structure of the RC structure is actively reinforcing the structure of the building which has suffered from aging, artificial and natural damage of the building. Among various reinforcement methods, epoxy adhesive is used to attach FRP in FRP reinforcement method which is reinforcing by attaching FRP to the structural part. At this time, the epoxy adhesive having a low critical temperature has a sudden adhesive failure upon exposure to heat, and thus, the development of an inorganic fireproof adhesive having a high critical temperature has progressed. Therefore, in this study, the compositional change of inorganic fire - resistant adhesive exposed to high temperature heat was analyzed by XRD.
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As the concentration of greenhouse gases in the atmosphere increases, the reduction of CO2 is gaining worldwide attention. In the construction industry, cement replacement materials such as fly ash and blast furnace slag were investigated to reduce CO2 emissions in cement production process. Precast concrete is used in the field after manufacturing in the factory in the form of pipes and bricks because of shortening construction period and cutting construction cost. According to the results of previous research, it is known that early CO2 curing in concrete using OPC or fly ash has an initial strength enhancement effect and can be used for precast concrete production. Therefore, the purpose of this study is to evaluate the strength improvement effect by confirming the initial strength improvement effect when blast furnace slag is mixed.
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In this study, we previously conducted a quick evaluation of cement powder map using mesiline and hydrometer. The experiment also confirmed the possibility of rapid quality evaluation of cement powder. In this study, further studies have been conducted to apply speed and cost more economical than conventional methods, and the possibility of applying this research is to be analyzed. The result of the experiment was 500 mL of a bottled water bottle with a solid edge for measurement convenience, and the hydrometer was determined to be B type. In addition, density values of each other by powder during the same time period are considered to be measurable, indicating large differences.
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In this study, the tensile properties of single and hybrid fiber reinforced cement composite according to strain rate was evaluated. Experimental results, in the strain rate 10-6/s, fiber reinforced cement composite showed improved of tensile strength and decrease of strain at peak stress as SSF volume content increased. In the strain rate 101/s, the single and hybrid reinforced cement composite's tensile properties are improved, because of the improved bond strength between the fiber and matrix. And hybrid fiber reinforced cement composite showed high energy absorption capacity, because the SSF prevented the cracking and fracture of the surrounding matrix when during the HSF pull-out.
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In recent years, harmful substances and fine dust in the air are caused by respiratory and cardiovascular diseases through various mechanisms when they are introduced into the human body through respiration, thereby exacerbating human health and causing cancer by prolonged exposure do. In order to prevent such fine dust from being introduced into the room and to improve indoor air quality, improvement of air quality has attracted attention. Among indoor air pollutants, fine dust and CO2 are pollutants that are directly affected by indoor number and activity. The purpose of this study is to evaluate the basic performance of cement matrix using photosynthetic bacteria as a basic study of fine dust and CO2 adsorption type matrix to suppress indoor air pollution and improve air quality.
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This study analyzed the physical properties of insulation materials upon completion of building completion years and found the suitability of the current energy performance analysis methodology to apply the insulation specified in the design drawings to the same thermal conductivity values as the new materials.
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Prediction of compressive strength of concrete by Maturity Method is applied in construction site. However, due to the use of wired type high-priced equipment, economic efficiency and workability are falling. In this study, a newly developed concrete embedded wireless sensor is used to perform a mock-up test. Next, the concrete compressive strength of the Maturity Method is predicted using Saul and Plowman's function as measured temperature data. The predicted concrete strength at the beginning of the age was the actual strength and stiffness, but the error rate was less than 1% at 28th day.
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Facilities used by senior citizens, infants, and disabled people have characteristics that make it difficult to escape on their own or require a lot of evacuation time. Therefore, to ensure safety in case of fire, clear measures for securing safety of facilities, fire response methods, and training are required in accordance with the regulations. In case of postnatal care center facilities, newborn babies and mothers reside 24 hours a day, and as they are located in high-rise and multi-use facilities, measures for fire safety are necessary, but the domestic manual lacks. Accordingly, a field survey for security of the manual revealed that the establishment of awareness and facilities on temporary waiting areas and smoke control, which are easy for evacuation and fire safety, was a problem.
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Seismic retrofitting technologies have been paid attention to structural engineers for rehabilitations of existing building structures vulnerable to seismic loading conditions. This paper introduces the traditional strengtheing method applying externally-bonded steel frames to column and beam elements, and compares with the improved scheme using the frames with additional energy dissipation systems. Throughout experimental studies, it was observed that the method can be effective for promoting the seismic performance of seismic force-resisting systems by guaranteeing strong column-weak beam mechanism. Compared to the traditional manner, it was found that the new scheme can be more efficient for confirming capacity design concept, while energy dissipation systems can provide additional damping effects corresponding to lateral deformation which occurs at seismic force-resisting systems exposed to seismic excitations.
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Environmental problems caused by air pollution have been considered as serious critical issues in global perspectives. Controlling greenhouse gases has become one of the major environmental problems in construction fields as well. However, similar studies were mainly focused on suggestion of various methodologies for measuring CO2 emissions of construction equipment and calculating emissions. This study aims to analyze the correlation between the CO2 emissions and RPMs of equipment by the construction process based on row data collected from construction equipment actually operated in job sites. This study allows site personnels to determine the amount of emitted CO2 under particular construction equipment under specific conditions during the targeted construction operations. The research findings expect to be used as fundamental informations for establishing environment-friendly construction operation planning.
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Recentely as high-rise buildings have been constructed, methods of managing concrete conveying pipes and preventing pipes from being blocked are important. The current methods determined by labors' experiences are not accurate and not efficient. The pipes vibrated and vibration frequencies were analyzed. The results obtained in this study showed that difference of the left concrete volume in pipes causes contrast of amplitude. Therefore, this study suggests that a prediction system can manage pipes by using vibration frequencies.
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The purpose of the safety management plan under the Construction Technology Promotion Act is to improve the quality and safety of construction engineers during construction work. To prevent a collapse accident of a facility after completion by preventing a collapse accident of gravel, an earthwork, a river structure or the like. In order to prevent collapses, the purpose of the project is to study measures to improve the ability of construction technology promotion law to ensure the quality of construction materials at the time of construction work.
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Cement is the most widely used but generates a lot of CO2, so we need a material to replace it. Using industrial by-products such as Silica Fume(SF), Blast furnace Slag(BS) and Fly Ash(FA) bring some advantages including CO2 reduction and resource recycling. However, there is a limit to improve performance when using only one material. Therefore, the synergy effects of No cement binary mortar and ternary mortar were analyzed and compared. As a result, No cement ternary mortar had the strength higher than binary mortar. among ternary mortars, the specimen mixed 50% of BS had the highest strength. However, when SF was mixed by 20%, the flowability reduces. so 10% of SF, 40% of FA and 50% of BS is considered as the optimal mixing ratio.
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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) straight 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 straight bars with large-diameter(43 & 57mm), it is necessary to find the modified factor or develop the new development length equation for large-size and high-strength bars.
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The present feasible tests are to develop the lightweight concrete using bottom ash aggregates and performed air foam for applying to sustainable high-insulation panel. The main variables investigated are water-to-binder, foam volume ratio, and curing conditions. Test results showed that the lightweight concrete possessed the compressive strength of 5~9 MPa at the air dry density of 951~1,139 kg/m3.
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To develop an effective shielding material for spent fuel that emits fast neutrons is necessary. In this study, thermal neutron and fast neutron shielding performance of polyethylene coated boron carbide-incorporated cement paste was quantitatively analyzed by Monte Carlo N-Particle transport code (MCNP) simulations. As the results of the simulations, fast neutrons were effectively shielded through large quantity of hydrogen and boron elements in polyethylene and boron carbide.
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The aim of this study is to investigate the properties of hardened mortar with chlorine by-pass system(CBS) in cement production in blast furnace slag(BS) mixed cement. Compressive strength had a tendency to be increased when the CBS Dust was replaced by 10% at the BS replacement rate of 0%. The 65% combination of BS showed a tendency to decrease as the CBS Dust exchange rate increases. Flexural strength was reduced as CBS Dust exchange rate increases in BS replacement ratio of 0%. The use of 5% of CBS dust can contribute to enhance the quality of non reinforced concrete.
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The purpose of this study is to investigate the compressive strength and mixing properties of the lightweight block, which has been manufactured without the pre-wetting process, in the lightweight block using domestic artificial lightweight aggregate. The test results of the specimens produced within 30 minutes after the preparation showed high compressive strength but poor permeability. Therefore, the elapsed time after the manufacture, which is expected to have required compressive strength and permeability, was about 60 minutes in this study.
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Radon is one of the substances that pollute the indoor air and is classified as a first-level carcinogen by the International Agency for Research on Cancer(IARC) together with asbestos, and it is reported that it can cause lung cancer. The World Health Organization(WHO) reports that lung cancer is the second leading cause of lung cancer, and 6-15% of lung cancer patients report lung cancer caused by radon. Radon occurs in cracks in concrete and aged buildings, and is detected in soil, rocks, groundwater, and so on. It is a colorless, odorless and tasteless gas which is adsorbed to dust in the air and enters through human respiratory system. This study used vermiculite (expanded vermiculite), which has excellent ion exchange ability and a large number of pores, and industrial by - product red mud which has heavy metal adsorption ability, in order to adsorb radon. A matrix capable of adsorbing radon was prepared, and the characteristics of each material were compared and analyzed.
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Although the disaster rate of the industry as a whole is on a downward trend, the disaster rate of the construction industry is on an ongoing trend. Therefore, in this study, we analyzed safety accident statistical data of the construction site over the past three years. As a result of the analysis, the incidence of disasters at small construction sites was very high. And the proportion of disaster occurred for workers who worked in less than 6 months even roughly 92.6%. In addition, as a result of analyzing the form of disaster occurrence, the crash was 34.1% and the fall was 15.1%. The analysis results of these construction safety accidents are to provide as a basic material for developing a policy that can prevent safety accidents and a safety accident prediction model.
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Recently, risk analysis studies regarding the architecture development project have been carried out by applying probabilistic method. However, it had a limit that this studies was conducted in only an apartment. Therefore, the objective of this study is to develop an optimal price estimation model that can be utilized on residential officetel project by applying Monte Carlo simulation. To achieve the objective, first, the variables are selected affecting the feasibility of an officetel based on literature review. Second, causal loop diagram is constructed by arranging the relationship between variables, then the import and expense model is suggested. Third, to carry out optimized parcel price, the range limits are set for each variables then Monte Carlo simulation is performed. In the future, the developed model is expected to help decision-makers as a tool to determine both risk and feasibility of the officetel development project.
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Rebar work is important in terms of cost and process of reinforced concrete construction along with formwork and concrete construction, and the quality of reinforced concrete construction has a great influence on the safety and durability of the structure. Therefore it is important to thoroughly inspect the steel reinforcement after casting the concrete because it is difficult to confirm the actual condition of the reinforcement. The purpose of this study is to develop an augmented reality system to visualize the records of bar placing work, which is increasingly utilized in the construction field. In order to improve maintenance of reinforced concrete, this study suggests a plan to effectively manage the drawing information including the structural drawing, the placing drawing, and the photographed image at the construction and inspection stage, and develop a system that utilizes augmented reality technology that can display the state of the inside of a concrete structure by superimposing it on actual environment.
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With the increase of tall building construction, efforts for enhancing constructability are required from the pre-construction stage. Therefore, in this study, we proposed an evaluation method of constructability performance by performing construction engineering activities at the design phase. Based on some results of previous studies, we estimated the importance of design factors and categories influencing the constructability in each engineering activity related to temporary work and then presented a method for evaluating the constructability performance of design alternatives.
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The main purpose of this study is to analyze the importance of the construction work of apartment buildings. The construction work operation was divided into five major tasks, which include: Schedule Control (P'1 - P5) Construction Management (C'1 - C'5), Environmental Management (E'1 - E'3), and Quality Management. Finally, this study derived major construction execution tasks through correlation between construction work and the original index and t-test.
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Many studies regarding construction safety management have been conducted. However, it is insufficient to research on external construction site. As a result, ordinary people around the construction site have injured and have a negative view when they think construction industrial since it has regarded having an overfull industrial accidents on media. To break the stereotype and prevention of accident on construction industry have been emphasized at this point in time, it is necessary to establish a comprehensive safety management system which is considered not only internal safety management but also external safety management. Therefore, the objective of this study is to develop the human accident risk quantification model by utilizing the third party payout data which occurred by incomplete safety management on external construction site. This study is conducted as a basic study for developing safety management manuals on internal·external construct site. In the future, it is expected to be used as a reference.
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Nuclear Power Plant consists of about 1.4 million facilities. and the design standards and design requirements for the continuos utilization and safety of facilities are complexly connected with the facilities. When a design change for facilities or design requirements is occurred at the time of construction or operation, there are a lot of facilities, design requirements, and design bases that are affected by the facilities or design bases being changed. The above design changes are so complex that the existing document-bases design change process is time-consuming and may also cause human error. In this study, we developed a design requirement taxonomy that can be applied to the data-centric design bases document that can improve it. To do this, we analyze the design elements from the highest level to the lowest level applied to the nuclear power plant, and classify the design elements according to the characteristics of the design elements.
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The domestic seismic retrofit guide was primally enacted in 1988, then the mandatory target have been consistently. As a result, the rate of earthquake-resistant is achieved 58.3% in public facilities. On the other hand, the rate of earthquake-resistant is low as 24.8% in education facilities. As education facilities damaged from Gyeong-ju, Po-hang earthquake occurred in South-Korea and the rate of earthquake-resistant is low, the seismic retrofit of existing education facilities got to be ordinary people's interest. Therefore, domestic researchers have been developed seismic retrofit methods which can apply to existing educational facilities, It is expected to become more active in the future. However, it is insufficient to consideration that how far domestic technology has been developed. Therefore, the objective of this study is to measure the level of domestic research through comparative analysis between domestic and foreign researches that seismic retrofit methods which can apply to existing educational facilities.
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The purpose of this study is to analyze the work of the existing manpower dependent cleaning method by investigating the window cleaning site. In this study, detailed work contents were confirmed by on-site investigation and interview with experts, and the relationship, procedure, repetition work, and time required for each work were analyzed. The future analysis results will be used as a basic data for comparative analysis of productivity and economical efficiency with the window cleaning device to be developed.
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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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This study the workability of synthetic resin form was examined through field application. results there was no warping or bulging of the mold during concrete placement in the field application. Also, the concrete surface finish of synthetic resin form was better than that of euro-form.
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This study was performed to develop the lifting pallets for the application of smart skin system when remodeling the balcony of apartment house. For this purpose, the smart skin system based on IoT, combining window, BIPV, ESS, air purifier applied in this study was examined. The study developed and presented a foldable double pallet considering the load (about 2Ton) and specification (width 7m × height 2.6m × width 1.3m) of the smart skin system. In future research, it is necessary to verify the application of the foldable pallet in this study.
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Seat waterproofing materials applied to the roof of a building concrete structure inevitably produce joints and are applied with opposite dam joints or overlapping joints depending on the waterproof material applied to the top of the sheet. In this case, the joint performance is determined by the material at the top, rather than by the superimposed joint. In order to solve this problem, various reinforcements have been used to apply to the connecting parts of the opposite dam, but the problem of attachment between different materials or the lack of reinforcement of the joint tape has not been solved. Therefore, for the purpose of securing tensile performance to the joints, this study is used as a reinforcement for the joints of PP materials with high tensile performance and as a reinforcement for nylon materials.
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The RC buildings which are constructed on the seaside are followed by KBC(2016) to achieve the minimization of durability damage. To control the corrosion of the reinforced steel bar by salt attack, W/C should be under 0.4 and specified concrete strength is more than 35MPa in the concrete/building construction standard specification. Ready mixed concretes which have usually include the admixtures in Busan were tested to certify the salt attack durability. In the same specified concrete strength, remarkable salt attack durability was evaluated in comparison to OPC.
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The purpose of this study was to find out harmful effects of concrete, an essential material in modern architecture, on the human body. Based on the results from animal testing, we can consider the effects on the human body. The results of this study were as follows; Experimental Mouses in concrete have low body temperature due to cold radiation and more aggressive due to cold stress. Therefore, Cold radiation, a property of concrete, makes body temperature lower and affect the body's immune function.
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As the air pollution progresses, the pollution degree of the indoor air quality is increased, and when the pollution degree of the indoor air quality is increased, it causes respiratory diseases and skin diseases. In addition, volatile organic compounds are released from the materials used for architectural interior decoration, and volatile organic compounds are the main cause of polluting indoor air quality. In order to improve indoor air quality, we tried to secure indoor air quality pollution by using photocatalyst which has the function of decomposing harmful substances. photocatalyst is a material that promotes chemical reaction by absorbing light. The photocatalyst used in the experiment was TiO2, In this study, an adsorption type hardener for reducing volatile organic compounds was prepared by photocatalytic reaction. the formaldehyde and CO2 concentrations of the cured products were analyzed according to the TiO2 content.
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In this study, surface spalling and explosive spalling of ring-type ultra-high strength concrete under rapid heating and slow heating were investigated. In rapid heating, the internal temperature difference of the concrete is large, so that continuous surface spalling occurs. However, in slow heating, the difference in the internal temperature of the concrete is small, resulting in explosive spalling at a time. Since the heating condition has a great influence on the internal temperature of the concrete, it is necessary to consider the spalling of the concrete under various heating conditions.
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In this study, the current tendency to replace a large amount of material admixture, which is fly ash (FA) and blast furnace slag (BS), into concrete is that high-grade cheese high admixture of high fluidity concrete In consideration of the substitution rate, we considered J-Ring to investigate the influence on the segregation resistance and the method of evaluating the classical segregation. In addition to the admixture replacement rate in the study results, the EIS using J-Ring became lower and the percentage of vehicles with segregation increased. Such a tendency is considered to be positive when J-Ring is used when segregation is judged if segregation degree is similar to EIS using J-Ring.
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In this study, the characteristics of the Mock-up test were reviewed to analyze the applicability of the coal gasification slag (CGS) from the integrated gasification combination Cycle (IGCC) to the concrete fine aggregate. The analysis shows that CGS and crushed sand mix is the best combination of CGS combined with about 50 % 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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In this study, it evaluate the impact resistance of UHPC by repeated impact. smooth steel fiber and polyvinyl alcohol fiber were reinforced in UHPC respectively. Overall, the impact resistance of the specimens reinforced with 0.4vol.% PVA fiber was high, and the crater diameter was small in specimens using 13mm fiber. When 19 mm steel fiber is used, the fracture depth is small due to the increase of macro crack resistance compared with other specimens. On the other hand, in the case of the fracture area, it is considered that the use of the fiber of 13 mm causes an increase in the stress dispersion effect to occur small.
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In this study, the adhesion performance of the adhesive between the concrete base and the fiber panel was verified through experiments. Attachment to all three types by applying adhesive to panel and attaching to CRC board surface, method of applying adhesive to CRC board surface by panel, method of applying adhesive on panel and CRC board surface respectively, As a result of the performance test, the adhesive strength of the panel attached to the panel on the CRC board after the application of the adhesive was highest on both the back surface of the panel and the surface of the CRC board.
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Researches for the development of renewable energy as a fuel substitute for global warming and depletion of petroleum resources are actively being carried out. Among them, the annual growth rate of PV generation is 20.73%, which is higher than other renewable energy sources. However, the production of 1 ton of polysilicon, which is known as a raw material for solar power generation panels, generates 2 tons of waste. As the demand for PV panels increases, the problem of the treatment of polysilicon sludge is attracting attention, and studies on the utilization of polysilicon sludge are needed. Therefore, in this study, the applicability of polysilicon sludge treated as industrial waste to the lightweight panel for architectural purposes was examined.
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In this study, use to CBS Dust as substitution of cement was explored. And the CBS Dust was intended to be used as a cement substitute, and the possibility as a potential water hardness stimulant for BS was investigated. Test results indicated that it can be used in with BS for a potential hydroponic stimulant.
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In this study, TGA analysis of hardened cement paste with fire damage was performed. The mass reduction rate of 600 ℃ specimens was about 22 ~ 25%, and the sample of 800 ℃ showed the mass loss rate of 9 ~ 13%. As the target temperature and hold time increased, the mass reduction rate decreased. As the depth increased, the mass reduction rate decreased.
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The purpose of this study is to confirm the adhesion performance of the three - dimensional forming fiber panels by the dimensional forming angle. As a result of applying the three dimensional surface shape to the back side of the fiber panel and testing the adhesion strength by the three dimensional forming angle, it was confirmed that the bonding strength of the specimens to which the dimensional molding was applied was higher than that of the non dimensional molding. In addition, the highest adhesion strength was confirmed in a specimen having a three-dimensional forming angle of 70 °.
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In this study, the objective of this study was to evaluate the adhesive characteristics of existing self-adhesive rubber asphalt sheet, butyl sheet and acrylate sheet in a low temperature environment through Tack Rolling Ball Test to obtain basic data on acrylate. As a result of this experiment, in the case of the self-molding rubber asphalt sheet and the butyl rubber sheet, the compound of the sheet was frozen in the low temperature environment and the iron bead was separated. On the other hand, the acrylate sheet did not freeze the acrylate even at 0 ℃, It is confirmed that the measured value is shown by Ball Test.
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In this study, the performance of acrylate was evaluated by using acrylate composite waterproof sheet. Through this experiment, the waterproof sheet plays a primary role of waterproofing. When the water leakage occurs, the acrylate reacts with water and expands, and the performance of the self repairing of the damaged part is confirmed by temperature.
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In the case of conventional ultra-fast hardness membrane waterproofing material (polyurea, etc.), damage such as breakage or tearing occurred frequently at the time of cracking of the surface after waterproofing. In this study, it is suggested that a waterproof layer can not cope with the occurrence of cracks at the same time by applying the soft type waterproofing material of soft type at the lower part of the construction method (securing of elongation) To minimize the possibility of water resistance.
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Color concrete is produced by adding white portland cement and coloring agent. In Korea, colorant added to color concrete is expensive, durability evaluation in external environment is not verified and there is a tendency to avoid color concrete pouring. Red mud with a water content of 50% was prepared in liquid form using appropriate mixing water and additives for recycling as a coloring agent, the liquefied red mud manufactured was intended to show the possibility of using color concrete. In this paper, the application of red mud as an industrial by - product as a coloring agent for color concrete was investigated for the practical use of liquefied red mud by liquefying red mud and producing retaining wall block. As a result, it was found that all of the specifications stipulated in SPS-KCIC0001-0703 are satisfied.
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In this study, an inflated resistance test is conducted out of the nine test items of KS F 2622 using an appropriate series of waterproof materials, and the results are reported and compared to the performance range presented in the KS F 2622 inflated resistance test.
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Leakage problems in underground spaces of domestic apartments is becoming more serious and legal disputes related to leakage problem have become more commonplace. In this regard, leakage problem is not only a problem in construction, but is also a concern from a societal aspect. In this paper, we propose the details of a below-grade waterproofing design and specification standards of specific areas and sections of residential apartment buildings, and propose that a detailed examination of positive-side waterproofing methods is required.
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In this study, wind pressure resistance test was carried out among the nine test items of KS F 2622 using five types of water-tight material. After comparing the results with the performance range of the current KS F 2622 wind pressure resistance test, it is recommended to check the adequacy of the addition of the combined series.
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KS standards mostly relate to single component material evaluation, so in cases of underground structure environments, most cannot predict the existing composite forms of deterioration, resulting in the applied waterproofing materials becoming unable to respond to these damaging factors. Current domestic waterproofing market in Korea mainly uses single-ply waterproofing materials comprised of coatings or waterproof sheets and two or more-ply composite waterproofing methods. In order to evaluate these types of composite waterproofing systems, a new test equipment and method that incorporates various deterioration conditions (joint displacement, chemical exposure, water pressure etc) was developed. In a comparison testing, the results showed that flexible type materials have higher response performance towards joint displacement than the hardened material.
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This study presents the standard methods of diagnosis and repair to prevent and maintain the durability degradation caused by leakage cracks in underground structures in Korea. The third part after the announcement of the existing maintenance plan, The environmental characteristics and leakage condition of underground structures, the causes of deterioration of underground concrete structures, and countermeasures and leakage equipment were 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 acrylics. As a second study, it is confirmed that leachate can be used as a repair material by considering long time under water stability, elongation range test, fatigue resistance test, tube stability test, damage recovery performance ana temperature stability considering leakage environment for polyacrylate. In addition, this material is applied to Expansion Joint to perform leakage repair, and to verify the effect of repairing leakage by monitoring and visual observation of concrete humidification.