• The Journal of Engineering Geology
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• v.30 no.4
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• pp.541-555
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• 2020

The grouting method is used for reinforcing and waterproofing the soft ground, increasing the bearing capacity of structures damaged by lowering or subsidence due to rise and vibration, and for ordering. This study attempted to develop a blast furnace slag-based cementless grout material to increase the strength and hardening time of the grout material using reinforcing fibers. In this regard, in this study, it was used in combination with calcium hydroxide, which is an alkali stimulant of the three fine powders of blast furnace slag, and the content of calcium hydroxide was used by substituting 10, 20, and 30% of the fine powder of blast furnace slag. In addition, in order to compare the strength according to the presence or absence of reinforcing fibers, an experiment was performed by adding 0.5% of each fiber. As the content of carbon fibers and aramid fibers increased, the uniaxial compressive strength increased, and it was confirmed that the crosslinking action of the fibers in the grout material increased the uniaxial compressive strength. In addition, it was confirmed that the gel time sharply decreased as the content of the alkali stimulate increased.

• Journal of Fashion Business
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• v.16 no.3
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• pp.13-31
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• 2012

The purpose of the study was to analyze the work clothes' clothing comfort and wearer mobility of painting workers with the consideration of the work environment features in the machine and shipbuilding industries in South Korea. A questionnaire survey was conducted for the study, which consisted of questions on the clothing comfort and wearer mobility aspects of painting work clothes by clothes types and body parts. The work clothes' clothing comfort and wearer mobility levels were scaled in 5 points i.e. 1(: very tight/very uncomfortable) to 5(: very slack/very comfortable). The painting work environmental hazardous features were considered as high impact levels of workplace temperature, oxygen deficiency, organic solvent, toxic gas factors while metal fragment factor only impacts 'low' in the painting processes with the findings throughout this study. Since the painting work consisted of surface washing and the spray and touch-up painting processes, which was carried out in an outdoor work place, the painting work clothes should meet high performance of waterproofing from the painting material and air permeability specially in summer as well as thermal performance in winter. The subjects painting workers' assessment of the existing work clothes' clothing oppression was in the levels between 3 (i.e. moderate) and 4 (i.e. comfortable) in a range of 1 to 5 points. The existing painting work clothes' wearer mobility was evaluated 'very uncomfortable' in all work clothes parts, especially, armhole length, biacromial breadth, sleeve length of the jumper; and body rise, waist, hip, thigh and knee circumferences of the pants.

• Korean Journal of Construction Engineering and Management
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• v.6 no.3 s.25
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• pp.128-134
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• 2005

Up to now, the various water proofing methods and materials have been developed. For the water proofing methods, poly-urethane membrane method is one of the commonly used and increase market share in water proofing industry due to it's many advantages. However, in spite of it's many advantages over other water proofing methods, water proofing defect occurs frequently. With this respect, the study investigate water proofing defect causes in roof water proofing. The study investigate 13 water proofing construction site in Sunchon city in oder to find urethane membrane defection causes and their type. As a results of the study, the followings are founded. 1) Among various water proofing defection causes, problems of water remain phenomenon due to surface horizontal level defect which occupy $25\;\%$ of total defect causes is the most commonly occur. 2) The second defect cause which occupy $15\;\%$ of total defect causes is the swell up phenomenon due to surface dry problem. For the prevention of water proofing defection in roof using urethane membrane, the followings are recommended. 1) Faultless surface treatment before using urethane membrane 2) Develop improved urethane membrane material 3) Improve urethane membrane construction technique

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.6
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• pp.665-674
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• 2015

A TSL (Thin Spray-on Liner) which consists of polymers has a higher initial strength, faster construction time and higher waterproofing performance than the conventional cementitious shotcrete. Main supporting mechanism of TSL is the adhesion and tensile strength which is distinct from the conventional shotcrete. Even though highly in demand due to its outstanding characteristics, TSL is not yet well-known support material. In this study, to evaluate contact behavior of TSL, numerical analysis was performed with comparing result from laboratory tests. From the analysis, cohesive behavior at the contact surface between TSL and rock can be evaluated by using combination of cohesive and the damage model. In addition, results show that the cohesive stiffness controled slope between force and displacement, the fracture energy controled level of force at the contact.

• Journal of the Korean Institute of Educational Facilities
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• v.24 no.6
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• pp.11-18
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• 2017

Education facilities have much affect to make a good condition for the learning environment. Therefore, various approaches have been conducted to improve the physical, social and educational achievement. Especially, the physical aspect is very important to get rid of the building defect and improve the student their learning environment. For these, it needs to explain the performance and function of components and materials, which is linked with the deterioration degree. The deterioration degree is a imperative factor to make a decision whether the component would be repaired or not and to provide the repair scope of its component. In this paper, it aimed at making the deterioration degree model of roof proof under the hypothesis of which deterioration degree would be equal the repair cost at this time. Results of the study are shown that first, the $3^{rd}$ function is most proper to explain the deterioration degree model among 11 functions in view of resulted statistics. Second, the inflection of deterioration is shown at 15yr of the elementary school and 13yr of the middle and high school. This study has a limit of disclassification of the component or materials and it is, therefore, favorable to include the classification of waterproof material and work. These results would make a change from the breakdown maintenance to preventive maintenance and give a decent the learning environment for student.

• Journal of Fashion Business
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• v.16 no.6
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• pp.21-35
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• 2012

In consideration of the injuries and deaths occurring at manufacturing sites due to the use of inappropriate work clothes or safety devices, this study aims to categorize manufacturing work processes to develop functional work clothes for heavy industries including the automobile, machine and shipbuilding industries in South Korea. Defining the features of the work environments and work postures of these industries provided for a categorization of the work processes which would enable the development of suitable work clothes for each work process' category. The results of the study based on a questionnaire survey are as follows: Work process category 1, including steel panel pressing and auto body assembly, final inspection (in automobile) and inspection (in machine), requires work clothes with upper body and arm mobility and performance to protect from the toxic fume factor. Work process category 2, consisting of welding (in automobile), cutting-and-forming (in machine) and attachment-and-construction (in shipbuilding), requires clothing elasticity, durability and heat and fire resistance. Work process category 3 comprising welding and grinding in the machine and shipbuilding industries, requires work clothes' tear resistance and elasticity, particularly for lateral bending mobility, and work clothes' sleeves' and pants' hemlines with sealed designs to defend against iron filing penetration, as well as incombustible and heat-resistant material performance. Finally, work process category 4, including painting in machine and shipbuilding, requires work clothes with waterproofing, air permeability, thermal performance, elasticity, durability and abrasion resistance.

• Polymer(Korea)
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• v.32 no.6
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• pp.555-560
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• 2008

Polymer-modified mortars have been largely used as paving materials, flooring, waterproofing material, adhesives, anticorrosive linings, deck coverings, and other various materials. The various types and properties of the mixed polymer largely affect the characteristics of polymer-modified mortar that has been mixed with polymer latexes. Consequently, its application purposes are varied according to these properties. This paper investigates the typical properties of polymer-modified mortars that contain styrene and butyl acrylate latexes and styrene butadiene rubber. They are then tested to obtain air contents, water-cement ratios, flexural and compressive strengths, water absorption, and chloride-ion penetration. From the test results, the superior flexural strength of polymer-modified mortars is obtained at a S/BA-2 and a polymer-cement ratio of 20%. And, the water absorption and chloride ion penetration depth are greatly affected by the polymer-cement ratio rather than the types of polymer. In the polymer-modified mortar and concrete structures, aggregates are bound by such a co-matrix phase, resulting in the superior properties of polymer-modified mortar and concrete compared to conventional mortar and concrete.

• Journal of Sensor Science and Technology
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• v.32 no.5
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• pp.320-327
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• 2023

In this study, an FPGA-based sealer inspection system was developed to inspect the sealer applied to install vehicle glass on a car body. The sealer is a liquid or paste-like material that promotes adhesion such as sealing and waterproofing for mounting and assembling vehicle parts to a car body. The system installed in the existing vehicle design parts line does not detect the sealer in the glass rotation section and takes a long time to process. This study developed a line laser camera sensor and an FPGA vision signal processing module to solve this problem. The line laser camera sensor was developed such that the resolution and speed of the camera for data acquisition could be modified according to the irradiation angle of the laser. Furthermore, it was developed considering the mountability of the entire system to prevent interference with the sealer ejection machine. In addition, a vision signal processing module was developed using the Zynq-7020 FPGA chip to improve the processing speed of the algorithm that converted the profile to the sealer shape image acquired from a 2D camera and calculated the width and height of the sealer using the converted profile. The performance of the developed sealer application inspection system was verified by establishing an experimental environment identical to that of an actual automobile production line. The experimental results confirmed the performance of the sealer application inspection at a level that satisfied the requirements of automotive field standards.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.6
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• pp.1059-1075
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• 2017

The objective of this study was to evaluate the freezing and thawing resistance of the existing drainage system for leakage treatment of underground concrete structures operating in cold regions. The freezing and thawing test was conducted on 4 types of drainage system specimens to evaluate the freezing and thawing resistance of the drainage system. The freezing and thawing resistance was evaluated on 4 types of Hotty-gel, as a waterproofing material, connection methods and on two methods to fix the drainage board with Hotty-gel on the surface of cement concrete specimen. One cycle of the freeze-thaw testing was 48 hours (24 hours of freezing and 24 hours of thawing), and the temperatures of freezing and thawing were at $-18^{\circ}C$ and $10^{\circ}C$, respectively. Among the 4 types of Hotty-gel connection methods, leakage occurred after 28 cycles (8 weeks) of freeze-thawing only in the Hotty-gel connection method with the 'V' groove applied to the corner of the drainage board. No leakage occurred in the 3 types of Hotty-gel connection methods. In two fixing methods, leakage occurred in the method of fixing the drainage board on the cement concrete specimen using the washer, screw and plastic wall plug. Leakage occurred at one point after 10 cycles (3 weeks) of freezing and thawing. After 28 cycles (8 weeks) of freezing and thawing, leakage point increased to 5 points. As time passed, the leak point was not increased, but the amount of leakage was increased at each leak point. The Hotty-gel connection method with cross-sectional diagonal shape was evaluated to be the highest in the production efficiency considering the production time and manufacturing method of the Hotty-gel connection shape. In the construction efficiency considering the construction time and construction method, the fixing method of air nailer, fixed nail and washer was superior to that of the washer, screw and plastic wall plug.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.4
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• pp.177-186
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• 2005

The latest concrete structure has showed that the deterioration of durability has been increased by the damage from salt, carbonization, freezing & thawing and the others. Therefore, the measures for the concrete which has deteriorated durability have been taken. Among them, it has been often used that surface treatment which cuts off the deterioration factors of durability by protecting the surface of concrete. However, troubles such as fracture and rupture in the repair layer have been reported as time goes by due to the difference between the organic repair material like epoxy and concrete properties. Researchers have been developing the repair material which can cut off the deterioration factors of durability such as $CO_2$ gas, chloride ion and water by making the formation of concrete elaborate through the reaction with calcium ion when the surface improving agent is coated on the concrete. The main ingredient of that is inorganic substance which is the same as the concrete property. This study was evaluated the surface improving agent for permeability, watertightness, air-permeability, chemical resistance and elution resistance. As a result, it has been reported that the surface improving agent improves watertightness and air-permeability by penetration more than 10mm within concrete. Therefore, it is concluded that the surface improving agent developed in this research prevents deterioration of concrete durability when it is coated on the concrete structure.