• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.165-172
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• 2021

The purpose of this study is to investigate the carbon capture capacity of various inorganic materials. For this purpose, the change in property of ordinary Portland cement (OPC), blast furnace slag fine powder (GGBS), and circulating fluidized bed boiler ash (CFBC) due to carbonation were analyzed. Carbonation curing was performed on all specimens through the accelerated carbonation experiment, and the amount of carbon capture was quantitatively analyzed by thermogravimetric analysis according to the age of carbonation. From the results, it is confirmed that the carbon capture capacity was shown in all specimens. The carbon capture amount was shown in the order of CFBC, OPC, and GGBS. The 28-day carbon capture of CFBC, OPC, and GGBS was 3.9%, 1.3%, and 9.4%, respectively. Carbon capture reaction occurred rapidly at the beginning of carbonation, and occurred slowly with increasing age. SEM image analysis revealed that an additional product generated by carbonation curing in all specimens was calcium carbonate.

• International Area Studies Review
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• v.20 no.4
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• pp.3-22
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• 2016

This study analyzed the pattern of Myanmar's trade with east asia countries, Korea, China and Japan. By using RCA index and TSI index, the comparative advantage and trade specialization of Myanmar are analyzed. UN COMTRADE data from 2012 to 2014 is analyzed. After the economic sanction against Myanmar was lifted, the volume of trade of Myanmar was increased sharply as well as the trade structure is changed. The volume of trade in primary industry is decreased while the manufactured industry takes more share of trade volume. The comparative advantage of manufactured industries took more steps while those of primary industries lose. In the trade with Korea, China and Japan, Myanmar exports labor intensive products and primary goods. Trade relationship beteen Korea and Myanmar is analyzed to be primary step, while China's and Japan's are going to be advanced. China and Japan are entering to the stage of international value chain system by using abundant labor of Myanmar.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.5
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• pp.68-74
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• 2019

In this study, the mechanical property and durability of improved bond performance mortar shotcrete was investigated. Mortar shotcrete was prepared by replacing coarse aggregate with 100% fine aggregate in the shotcrete mixture proportion proposed in the road construction standard specification. OPC, GGBFS and anhydrite were used as binders, and polymer powder was substituted for 1% and 2% of binder for improving bond property. From the experimental results, it was found that the compressive strength decreased with increasing polymer addition, but the bond strength increased. The addition of polymer to mortar shotcrete also reduced the drying shrinkage and improved the resistance to carbonation. Initial hydration heat of mortar shotcrete decreased with the addition of polymer, and it was judged that the initial compressive strength decreased.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.2
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• pp.122-129
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• 2019

Cracks in concrete structures are inevitable phenomena caused by shrinkage, hydration heat, and external loads. These cracks facilitate the penetration of external harmful ions into the concrete, which greatly reduces its durability. Recently, self-healing concrete has been actively studied. Also, self-healing fiber-reinforced concrete have been studied to control the crack in concrete and to maximize the shelf-healing capability. In this study, mortar specimens containing PVA fiber, fly ash and crystalline admixture were fabricated. The compressive and flexural strength were evaluated. Also, the self-healing performance was evaluated by the absorption test. From the results, it was confirmed that the amount of water absorbed by healing of the crack decreased as time increased. It was also found that PVA fiber is beneficial for the production of calcium carbonate, an additional healing product.

• Journal of KIBIM
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• v.10 no.4
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• pp.50-59
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• 2020

Recently, the government has actively promoted the introduction of BIM at the national level to improve the efficiency and productivity of the construction industry, and private interest in the application of BIM has also increased. However, despite the large amount of references and information, not much research has been done in quantitative ways to accurately measure the performance of BIM projects. The purpose of this study is to review performance measurement cases using ROI, investment effect analysis, and queue model analysis using domestic and overseas BIM guideline research and to present standard templates that can quantitatively measure BIM performance records according to domestic conditions based on this. Performance measurement trends and cases according to the application of BIM were analyzed, and nine quantification elements were derived from this, and based on this, a performance measurement data collection template at the BIM life cycle stage was prepared. Detailed items and contents were prepared for the nine quantification elements, and the final template consisted of a total of 43 questions, divided into the entire stage (15), the beginning (8), the middle (8), and the latter (12) areas. It is expected that by using the standard template of railway BIM performance records developed in this study, the BIM design stage will be diagnosed and the deficiencies will be supplemented, which will be the basic data for measuring actual quantitative performance in all life cycle performance of future BIM projects.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.5
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• pp.95-102
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• 2022

Recently, there has been a growing interest in reducing greenhouse gases in all industrial fields. In the construction industry, studies have been conducted for the use of high-volume fly ash concrete to replace cement with fly ash. Quantitative measurements of cement hydration and fly ash reactivity enable a clear understanding of the strength development mechanism of high-volume fly ash concrete. It is very difficult to describe the reactivity in a simple way because the hydration and pozzolanic reactions of cement paste containing fly ash are very complex and the composition of the hydration product cannot be accurately determined. This study investigated the hydration and mechanical properties of high volume fly ash (HVFA) cement according to the substitution rate of fly ash (FA). The hydration degree of cement and the reactivity of FA were evaluated through the selective dissolution method and the non-evaporable water content of the paste according to age. In addition, compressive strength was measured using HVFA mortar specimens according to age. As a result of the experiment, as the substitution rate of fly ash increased, the hydration degree of cement increased, but the reactivity of FA decreased.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.157-164
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• 2021

Recently, a number of studies have been conducted on photocatalysts and adsorbents that can remove harmful substances to improve environmental problems related to fine particles. In this study, a porous foam composites were fabricated using palm-based activated carbon having a large amount of micro-pores and foam concrete with a significantly larger total pore volume compared to general construction materials. To evaluate the adsorption potential of fine particles, the pore structure of the foam composites were analyzed. For the analysis of the pore structure of the foam composite, BET and Harkins-jura theory were applied from the measured nitrogen adsorption isotherm. From the results of the analysis, the specific surface area and micro-pore volume of the foam composite containing activated carbon increased significantly compared to Plain. As thereplacement of activated carbon increased, the specific surface area and micro-pore volume of the foam composite tended to increase. It seems that the foam composite has high adsorption performance for gaseous fine particle precursor such as nitrogen oxides.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.120-127
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• 2022

Nitrogen oxide(NOx) is a major cause of air pollution, exists in the form of nitrogen monoxide and nitrogen dioxide, and is harmful to the human body. Recently, a number of studies to reduce NOx in the atmosphere have been conducted, and these efforts have been the same in the field of construction materials. It is known that NOx can be efficiently removed by using a photocatalytic reaction. In this study, the NOx removal performance of the foam composite using activated carbon(AC) and titanium dioxide(TiO₂) was investigated. AC was used to enhance the photocatalytic reaction of TiO₂ by increasing the internal specific surface area of the foam composite. In this study, foam composites were prepared using the substitution rate of AC as the main variable. The NOx removal performance of specimen was evaluated according to the test method presented in ISO-22197-1. The specific surface area of the foam composite showed a tendency to increase according to the AC content, but decreased at 15% or more. Also, when the AC substitution rate was 15%, the NOx removal efficiency was the highest.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.112-119
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• 2022

Recently, as carbon neutrality has been important factor in the construction industry, many studies have been conducted on the high-volume fly ash concrete. High volume fly ash concrete(HVFC) is usually made by replacing more than 50% of cement with fly ash. However, HVFC has a disadvantage of low compressive strength in early age. To overcome this shortcoming of HVFC, improve this, interest in techonolgy using nanomaterials is increasing. Nano silica is expected to improve the early age strength of HVFC as a pozzolanic material. This study investigated the effect of nano silica on the early hydration reaction and microstructure of HVFC. The early hydration reaction of HFVC was analyzed through setting time, isothermal calorimeter, compressive strength and thermal weight analysis. In addition, the microstructure of HVFC was measured by mercury intrusion porosimetry. From the test results, it was confirmed that nano silica increased the early age strength and improve the microstructure of HVFC.

• Journal of The Korea Institute of Healthcare Architecture
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• v.27 no.4
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• pp.61-70
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• 2021

Purpose: The study aims at identifying patient-related and environmental factors associated with an increased risk of falling and, therefore, both caregivers and designers can be aware of fall risk factors and can contribute to prevent inpatient falls in their own areas of expertise. Methods: A case-control study has been conducted, utilizing patient data and physical environmental data in the unit of General Medicine in the United States. The case-control study investigated data about patients who had suffered falls as well as patients with similar characteristics (e.g., age, gender, and diagnosis) who did not suffer falls. Results: The study identified both patient-related and physical environmental factors associated with inpatient falls. Morse fall risk score, patient visibility, and patient accessibilityB were identified as significant predictors to inpatient falls, when controlling for other significant variables. Implications: The findings of the study can provide implications to both caregivers and healthcare and hospital environment designers. Caregivers should give special attention to patients with high Morse Fall Risk Scores to prevent inpatient falls. Designers also need to examine and to fine-tune the unit layout of inpatient care units to maximize each patient room's patient visibility from the rest of the unit and patient accessibilityB from working areas of nurses.