• Applied Chemistry for Engineering
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• v.30 no.1
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• pp.39-42
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• 2019

We report on the design of oil-water separators and the selection of materials for the effective application of highly selective membranes fabricated by commercial PET (polyester) fabrics. The waterproof ability of PET fabrics was optimized to improve the separation selectivity. The density of individual PET fabrics should be over $60g/m^2$, and the multi-layered structure is more favorable for the waterproof ability together with maintaining the removal efficiency. For the continuous adsorption and removal process, the rotating perforated cylinder was selected, and covered with membranes. Furthermore, more improved and stable removal efficiency was obtained by installing floating baffles which forces the oil content to move toward membranes.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.3
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• pp.224-234
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• 2019

Waterproof layers are installed in civil engineering structures and bridge construction is commonly finished by applying a layer of regular or asphalt concrete above the waterproof layer. However, asphalt materials are susceptible to melting at high temperature due to its superior temperature sensitivity, and this causes the waterproofing material to melt due to the high temperature of the asphalt concrete, thereby increasing the defect occurrence rate due to the thickness reduction. In this study, tensile strength and elongation of hard and soft type of MMA(Methyl Methacrylate) applied to bridges were compared in accordance to standard performance criteria based on different mixture ratios. Results of comparative testing showed that hard MMA resin can display a satisfactory tensile strength, and soft MMA resin displays satisfactory elongation properties, but as the two resin types are separately used, neither types are able to satisfy the standard requirements outlined in KS F 4932. When the amount of the powder exceeds 56.25% of the total amount, voids are generated on the surface after curing and self leveling was impossible and a heterogeneous surface is formed. Furthermore, when the hard resin: soft resin: powder mixture ratio was set to 15g: 85g: 150g. the tensile strength was $1.5N/mm^2$ and the elongation percentage was 133% which satisfy the tensile performance of KS F 4932.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2A
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• pp.169-176
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• 2010

Generally, poly-urea is widely used as waterproof coating material due to its superior adhesiveness, elongation capacity, and permeability resistance. In addition, it can be quickly and easily applied on structure surfaces using spray application. Since it hardens in about 30 seconds after application, its construction efficiency is very high and its usage as a special functional material is also excellent. However, currently, poly-urea is mostly used as waterproof coating material and the researches on its usage as a retrofitting material is lacking at best. Therefore, basic studies on the use of poly-urea as a general structural retrofitting material are needed urgently. The objective of this study is to develop most optimum poly-urea composition for structure retrofitting purpose. Moreover, the structural strengthening capacity of the developed poly-urea is evaluated through flexural capacity experiments on RC beams and RC slabs. From the results of the flexural test of poly-urea strengthened RC beam and slab specimens, the poly-urea and concrete specimen showed monolithic behavior where ductility and ultimate strength of the poly-urea strengthened specimen showed slight increase. However, the doubly reinforced specimens with FRP sheet and poly-urea showed lower capacity than that of the specimen reinforced only with FRP sheet.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.4
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• pp.553-561
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• 2020

Water-soluble rubber asphalt-based waterproofing material, which is one of the waterproofing materials for building structures, is mainly used indoors (toilet, kitchen, balcony, etc.). In general, asphalt-based materials are used for non-exposed installation, rather than as exposed type as they do not deviate from their usual basic black pigmentation, and water-soluble rubber asphalt-based coating waterproofing materials are basically limited to indoors because of their low physical properties. Accordingly, in order to improve the tensile and elongation properties, a silane coupling agent, an inorganic filler, and a processor oil w ere added to improve the physical properties, and accordingly, the basic physical properties of the outdoor coating waterproofing material quality standard were analyzed. As a result, the water-soluble rubber asphalt coating waterproofing material compared with the exposure quality standard showed a result that exceeded the basic physical property quality standard of silicone rubber in all items under test evaluation, but the tensile strength and tear strength of the first class of urethane rubber were chloroprene. It was found that the performance compared to the quality standards of rubber-based tear strength was about 34.2% to about 40.8%.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.185-190
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• 2005

Safe, economical and environment-friendly tunnel construction are required again along with social continuous development, the importance of waterproof work that is portion that actually all of user and builder can find that is embossed by tunnel construction's one of important construction. Also, ECB (Ethylen Copolymer Bitumen) sheet that is used in existing tunnel waterproofing method (ECB waterproofing method) being black because asphalt (Bitumen) is added, by purpose that make illumination of tunnel interior brightly and scar discovery eases in sheet with coating white film, but ECB that is used present according as ECB that asphalt is added does not satisfy high tensile strength of construction field, quality standard of extension. Also ECB denigrates color of black M/B that asphalt is excepted.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.3
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• pp.173-178
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• 2011

Gas diffusion layer(GDL) in PEMFC performs the discharge of water vapor smoothly. When GDL is revealed to cold environment, the freezing of the water droplet or water net in GDL occurs. The purpose of this work is to observe the cooling and freezing behavior of the water droplet which meets to the microporous surface and air under the various low temperature conditions. GDL was coated with waterproof material, which has three types of coating rate, 0, 40 and 60%. Water droplets in series of sizes on GDL were supercooled, frozen and crystalized orderly by circulating low temperature brine. The process of cooling was investigated with the temperature and the snapshot of the water droplet.

• Journal of the Korea Institute of Building Construction
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• v.21 no.1
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• pp.87-95
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• 2021

In this study, seven companies(A~G) designated as new construction technology selected and evaluated KS F 2622: Method of test for performance evaluation of membrane roofing systems that are similar to field application conditions. As a result of the test, it was confirmed that although all test specimens exceeded KS standards in the basic physical, it was difficult to obtain field quality performance in weak areas such as joints and vertical parts of the adhesive coating method in water-tightness, sagging resistance, swelling resistance tests except for fatigue(crack behavior) tests.

• Journal of Fashion Business
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• v.26 no.5
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• pp.122-134
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• 2022

This study is conducted on hardening leather with improved firmness and stability of shape, based on research on types and thickness of leather. The purpose of this study is to test the physical properties of the leather for molding to prepare the foundation for leather molding based on the test results using four methods by thickness of Vegetable and Split. The tests were conducted using a total of five leather types, including three types of vegetable leathers and two types of split, by thickness. Based on the testing method for leathers in KS M 6882, the tests were performed at 27℃ with relative humidity of 65±20%. The samples were prepared with cowhide, size 9cm× 2cm. The measurement parameters are length and width. thickness, volume, mass, density. Regarding the hardening treatment method, changes in appearance and major physical characteristics of leather were reviewed by soaking in hot water, dry heating, hammering, waxing, and olive oil coating. The study results are as follows. In planar works, it is judged that hardening work using a hammer is more suitable for stiffness or density in order to prevent easy breakage with adult muscle density, rather than boiling water or baking. In conclusion, there is no curling, soot, or breaking phenomenon, and the densest curing method is 50℃ for 20 sec of V2 and 75℃ for 60 sec of V2 in boiling water. The combination of paraffin treatment improve waterproof and quality.

• Korean Journal of Construction Engineering and Management
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• v.10 no.5
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• pp.123-134
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• 2009

Since 1970s, urethane waterproofing method is broadly used in rooftops, underground spaces, and sports stadium for its outstanding ultraviolet blockage, watertightness, and elasticity. However, development of slippage-resistance and endurance, improvement of function considering convenience and visually pleasing of users, urethane waterproofing method is necessary, since rooftops and underground spaces have slippage and external force risks. Therefore, many improved waterproofing methods are being developed and, recently, embo-thane waterproofing method, which applies embo-spray coating system, has been developed. This paper explains exposure, nonexposure, and floor-material of embo-thane waterproofing method, and then perform experimental study for comparison with urethane waterproofing method about tensile strength, coefficient of expansion, performance of bond, anti-abrasion, and slippage-resistance. In addition, the performance index was presented for the superiority of embo-thane waterproofing method compared to urethane by setting up evaluation criteria considering not only physical performance but also design side of embo-thane waterproofing method, and Value Analysis applying AHP. Also for an assessment considering uncertain result, Monte Carlo Simulation Method was used to operate reliability analysis through statistic approach method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.2
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• pp.110-116
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• 2013

A concrete structure has become bigger and higher because of development of construction technology and a change in construction environment. Also it tends to focus on repairing, reinforcement and exterior in harmony with environment for structure maintenance and performance improvement. The research is about eco friendly durable painting applicable to concrete structure using civil and architecture. it purpose to improve external beauties and durable problems due to flexibility by variation of temperature, adhesion of exterior wall, crack and delamination in existing organic and mineral painting. For those problems, we made a eco friendly pre-paint that is made with preliminary treatment mixture as a highly enriched waterproof agent and adhesive increasing agent in preprocessing mixture. Then we performed an experiment on durability of prevention neutralization of concrete, durability abrasion, hiding power, adhesion, temperature resistance and resistance to chemical attack. The result of an experiment shows that hiding power is over 0.96 in standard test, durability abrasion test got higher value 1mg than water paint 75mg and tensile strength is 6 times higher than standard waterproof specification.