• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.123-124
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• 2023

This study successfully developed a chromium-free paper-based analytical device (µPAD) for chloride detection in fresh concrete. The sensing materials were chemically synthesized and coated to the paper through drop casting. The fabricated µPAD was thoroughly tested with various concentrations of chloride ions. Upon interaction with the µPAD, the chloride ions in the solution react with a chromium-free silver compound, exhibiting a specific coloring height proportional to the absolute chloride concentration. The height of the color change during a reaction can vary based on the chloride concentration, which allows for predicting the chloride concentration in a solution. The results reveal that µPAD has extraordinary precision in identifying chloride in fresh concrete, which highlights its immense potential for future applications.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1303-1308
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• 2007

Recently, precast concrete tracks are replacing ballast track for efficient and economic maintenance of track. Precast concrete railroad tracks are manufactured in factory, and transported to railroad construction site for installation. Therefore, quality of precast concrete track itself should be sufficiently good. On the contrary to the convenient manufacturing of precast concrete track, the installation of a precast concrete track requires careful steps. Typically, a precast concrete track is placed on an approximately 15-cm thick lean concrete layer. A mortar is filled between lean concrete layer and precast concrete track to adjust the sloping angle of a precast concrete track for a safe train operation at a curvy section. Then, the use of filled mortarproduces a void underneath a precast concrete track, which is harmful to structural safety of a precast concrete track undercyclic loading. Therefore, it is essential to make sure that there is no void left beneath a precast concrete track after mortar filling. In the continuous resonance method, the amplitude of frequency response measured using an instrumented hammer and an accelerometer is plotted against a pseudo-depth, which is half of the wave velocity divided by frequency. The frequency response functions are measured at consecutive measurement locations, 6-cm interval between measurement points, and then combined together to generate a 2-D plot of frequency response. The sections with strong reflections or large amplitude of frequency response are suspicious areas with internal voids and unfilled areas. The 2-D frequency response plot was efficient in locating problematic sections just by examining the color shade of a visualized plot in 2-D format. Some of the problematic sections were drilled to make a visual inspection of mortar filling. The visual image of interface between mortar and precast concrete track was verified using the validity of the continuous resonance technique adopted in this research.

• Journal of Korea Game Society
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• v.8 no.1
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• pp.41-48
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• 2008

If an association for a color develops and comes to form any kind of common idea, a symbolic meaning is given to the color. It is called' symbolism of color' that color builds up an abstract general idea, an emblem, feeling except things concrete. The color of game is the visual element that one can be immersed in the game, the image which act as important meaning, the attribute of light, and visual perceptional factor. With form, motion, light and shade, the color function importantly as media which express a person and person's circumstance. In game, the color is used symbolically to suggest not only mental change of character but also the situation, mood, attribute and strength of energy. These transmission of meaning express symbolism of the color iconically. So, the color for image express of game take on universality. This study research that focus on how the symbolical meaning of the color is reflected in game.

• Korean Institute of Interior Design Journal
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• v.17 no.6
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• pp.207-215
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• 2008

Modern people come to have high standard and variety need for the oneself expression these days. This phenomenon also, appears in the house space clearly. There are design characteristics in an element expressing a lifestyle and personality in the house space and a living room is the space that is important at time to do a design characteristics plan. Therefore, this study is going to analyze the design characteristics of the apartment house which is a representative house type these days. Concretely, there are design characteristics that a color, an Image, a style. This study used questionary survey from June 10, 2008 to July 9. The color analyzed a color and tone through a color palette of PCIS and the living room image used SD(semantic differential method) method by a concrete analysis method. The result of the analysis were as follows; 1) Various colors and tone were prefer in a house future than the house where lived in. 2) It was done prefer to 'comfort' image for the future living room image in the future but 'provocative' image and 'splendid' were not done a choice 3) A 'modern style' was done prefer to of with a house living room style in the future.

• Korean Institute of Interior Design Journal
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• v.24 no.5
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• pp.42-50
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• 2015

In the 21st century, university library is changing into a new paradigm. Among others, color image emerges as an important aspect of the library. Up to now, studies on colors of indoor space have been limited on partial and specific spaces. But, this study, using the tool of emotional evaluation, aims to do a comprehensive research on color image of the whole space. This research uses the H University library completed in March 2015. This research is performed in the following procedure. First, previous related researches for the past ten years from 2005 to 2015 is examined, which will help understand the trends in this kind of research, and set up the concrete goal of research. By literature review, color image is established in the environmental psychological aspect. Second, to analyze colors, all the spaces of the library from the entrance lobby are filmed. Filmed images are changed into mosaic, and color palettes are composed, and color values are calculated using the Munsell color system. Third, emotional words are extracted, and emotional evaluation is made. Using the Semantic Differential scale method, emotional differences among subjects are compared, and the validity of the survey data is tested using the statistical program SPSS 18.0. As the outcome of the research shows, the color image and emotion in space are closely related. And, through emotion, it is possible to get color image, and this aspect can be scholastically systemized and developed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.05a
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• pp.183-186
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• 2008

Carbonation is measured as Phenolphthalein Solution, it is possible to confirm the scope of alkali through acid and basic reaction. Then, Concrete Basic Reaction is decided according to alkali concentration depending on Potassium Hydroxide Now that Carbonation is gradually produced toward inner side from outer side, with time going by, it doesnt work, to some adequate depth, in as fast time as compulsory facilitating test. Thus, this research thesis made a comparative analysis on concrete phenomenal discoloration borderline following Phenolphthalein Solution, as part of a bid to measure Carbonation. Also, the thesis measured Concrete Alkali Concentration. The result showed that concrete coloring is classified into red and scarlet according to alkali concentration, and into borderline breakpoint of the speckle of scarlet and carbonation reaction. The higher chroma becomes with concrete decolorizing, the higher alkali concentration becomes.

• International Journal of Highway Engineering
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• v.17 no.5
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• pp.33-38
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• 2015

PURPOSES : The purpose of this paper is to investigate the application of thermoelectric technology to concrete structures for harvesting solar energy that would otherwise be wasted. In various fields of research, thermoelectric technology using a thermoelectric module is being investigated for utilizing solar energy. METHODS: In our experiment, a halogen lamp was used to produce heat energy instead of the solar heat. A data logger was used to record the generated voltage over time from the thermoelectric module mounted on a concrete specimen. In order to increase the efficiency of energy harvesting, various factors such as color, architecture, and the ability to prevent heat absorption by the concrete surface were investigated for the placement of the thermoelectric module. RESULTS : The thermoelectric module produced a voltage using the temperature difference between the lower and upper sides of the module. When the concrete specimen was coated with an aluminum foil, a high electric power was measured. In addition, for the power generated at low temperatures, it was confirmed that the voltage was generated steadily. CONCLUSIONS: Thermoelectric technology for energy harvesting can be applied to concrete structures for generating electric power. The generated electricity can be used to power sensors used in structure monitoring in the future.

• Journal of the Regional Association of Architectural Institute of Korea
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• v.21 no.5
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• pp.117-124
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• 2019

When manufacturing concrete, several mineral admixture is added to improve the basic physical property and durability and to make economical concrete. Such mineral admixture includes fly ash, granulated blast furnace slag, silica fume, etc., and not only the studies about mixing these mineral admixtures but also the studies for the development of new materials have been steadily in progress. Recently, some researchers have found, as a part of the development of new materials, the rice straw ash can also be used as a pozzolanic material for concrete considering similar chemical properties of rice straw ash to that of rice husk ash. But there has been insufficient amount of study about it. So, this study was to investigate the possibility as mineral admixture of agriculture by-product, by analyzing properties of concretes using rice straw ash with replacement ratio in comparison with other mineral admixture. In order to measure amount of SiO2 of rice straw ash, XRF(X-ray fluorescence) analysis was tested. For the measure pozzolanic reaction of rice straw ash, pH change and color change was tested according to curing day. Also to evaluate properties of concrete using rice straw ash, slump test, air contents test and compressive strength was tested.

• International Journal of Highway Engineering
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• v.13 no.1
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• pp.177-183
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• 2011

VES-LMC(very-early strength latex modified concrete) has been widely used as repair material for bridge deck overlay or rehabilitation, because it could be opened to the traffic after 3 hours of curing. However, the bright color of VES-LMC disturb driver's sigh. A black VES-LMC, matching to asphalt concrete, was developed and applied at a filed for driver's comfort and safety. The black VES-LMC included 2% carbon black in cement weight ratio. A series of performance evaluation for black VES-LMC was done in terms of field applicability, pavement color and temperature change. The field applicability test result showed that there were no change of workability, slump and air void, and the compressive strengthen developed more than 20MPa after 4 hours of placement. The thermal stress of black VES-LMC was smaller than that of OPC and asphalt concrete, which means the stability of black VES-LMC. The performance evaluation result showed that the black VES-LMC could prevent road icing at below zero temperatures and promote thawing at melting temperature.

• Journal of the Korea Concrete Institute
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• v.14 no.3
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• pp.440-448
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• 2002

Waste glass has been increased with the development of industry. The utilization of waste glass for concrete can cause the concrete to be cracked and to be weakened due to an expansion by alkali-silica reaction(ASR). In this study, ASR expansion and properties of strength were analyzed in terms of waste glass color(amber, emerald-green), industrial by-products(ground granulated blast-furnace slag, fly ash), and the content of industrial by-products for reducing ASR expansion caused by the waste glass. The possibility of using glass ground as pozzolanic properties was also analyzed. From the result of this study, the pessimum size of waste glass was 2.5∼1.2 mm regardless of waste glass color. And the smaller than 2.5∼1.2 mm waste glass is, the more decreasing expansion of ASR is. Also, the combination of waste glass with industrial by-products have an effect on reducing the expansion and strength loss caused by ASR between the alkali in the cement paste and the silica in the waste glass, and the glass ground of less than 0.075 mm is applicable as a pozzolanic material.