• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.11 no.1
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• pp.47-52
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• 2005

The wasted plastic PC/ABS retainer, polyurethane foam (PUF) and vinyl (PVC) skin. In order to investigate the recycling process, the multi-layered instrument panel Each of materials separated was shredded and crushed to create many small particles respectively. The separation of the foam and skin and retainer of zigzagged air blower. Pilot tests performed at the equipment yielded 98.8% by weight of the available PVC and 99.3% by weight of the available PC/ABS respectively. Secondly, the thermal stabilizer and the compatabilizer have been used to improve the physical propertied of recycled materials.. The properties of recycled PVC materials resulted in about 50% compared to that of virgin materials after treatment by Pb-St thermal stabilizer. In addition, the properties of recycled PC/ABS materials was also obtained about 80% compared to that of virgn materials after treatment by PMMA compatabilizer.

• The Journal of the Korea Contents Association
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• v.14 no.9
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• pp.503-512
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• 2014

The study is based on the serious environmental problems occurring these days to acknowledge the consumers awareness and preference according with the coordination using recycled materials in the dining space. As the result, considered the consumers had lack in recognition of using recycled materials when they tried to use them in their normal daily life. Also the females were far more interested than the males with the usage of the recycled materials inside the restaurant and its interior image along with married persons had more positive attitude towards it than the unmarried ones. With education back ground, highly educated peoples really quite didn't prefer the usage of the recycled materials. According with the income, the high earnings and with the occupation, the professionals with specialized jobs considered the practical use of aspects more important than above. Therefore the needs to educate and promote the consumers to use recycled materials in their every day lives, it is required to build social responsibility and finding the essential meanings to save resources so that they can utilize them with converted recognitions.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.541-544
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• 2006

As the importance of recycled materials is being emphasized more in the Korean construction market, the production Quality has been improved to a significantly high level. Compared to the high quality, however, there are used very limitedly. Among recycled construction materials, recycled aggregates produced through the retreatment of waste concrete are drawing attention because of lack of natural aggregate and heightened consciousness of resource saving and environmental protection and, as a consequence, they are close to natural aggregates in terms of production technology and quality. Despite the high quality and productivity. however, the utilization of recycled aggregates is very low.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.1
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• pp.72-83
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• 2015

Underground transmission lines always generate heat and transmit heat through surrounding backfill materials. Therefore, in the design of power lines it becomes a very crucial factor to transfer heat effectively into the neighbouring soils. In this study, in order to enhance field applicability of recycled aggregates for backfill material of transmission lines, quality criteria and construction criteria were proposed, and thermal stability of power lines through field demonstration tests were analyzed. In the field tests, two types of recycled aggregates and sand which is currently used for backfilling were compared in terms of thermal behaviour. Test results showed that recycled aggregates represented similar trends with sand in temperature and moisture content corresponding to time lapse and distance from the heat source. Consequently, recycled aggregates can be utilized for backfill materials of underground transmission lines as a substitute material of sands.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.3
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• pp.63-69
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• 2010

This study investigates the chemical resistance of the recycled aggregate concrete containing calcined ground slag, fly ash, and diatom powder. The recycled aggregate which had the density of $2.48g/cm^3$, the absorption of 4.25%, and standard gradation was used and the concrete specimens were submerged in solutions of $Na_2SO_4$ and $CaCl_2$ at 10% concentration for 6 months. As the submersion result, pore volume of over $0.02{\mu}m$ diameter was formed less in the concrete specimens containing calcined ground slag, fly ash, and diatom powder than in the concrete without the pozzolanic materials and the result shows the effectiveness of the pozzolanic materials for the increase of chemical resistance of the recycled aggregate concrete.

• Environmental Engineering Research
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• v.21 no.4
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• pp.341-349
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• 2016

To improve the utilization rate of construction waste as mine backfilling materials, this paper investigated the feasibility of using recycled powder as mine paste backfilling cementitious material, and studied the pozzolanic activity of recycled construction waste powder. In this study, alkali-calcium-sulfur served as the activation principle and an orthogonal test plan was performed to analyze the impact of the early strength agent, quick lime, and gypsum on the pozzolanic activity of the recycled powder. Our results indicated that in descending order, early strength agent > quick lime > gypsum affected the strength of the backfilling paste with recycled powder as a cementitious material during early phases. The strength during late phases was affected by, in descending order, quick lime > gypsum > early strength agent. Using setting time and early compressive strength as an analysis index as well as an extreme difference analysis, it was found that the optimal ratio of recycled powder cementitious material for mine paste backfilling was recycled powder:quick lime:gypsum:early strength agent at 78%:10%:8%:4%. X-ray diffraction analysis and scanning electron microscope were used to show that the hydration products of recycled powder cementitious material at the initial stages were mainly CH and ettringite. As hydration time increased, more and more recycled powder was activated. It mainly became calcium silicate hydrate, calcium aluminate hydrate, etc. In summary, recycled powder exhibited potential pozzolanic activities. When activated, it could replace cementitious materials to be used in mine backfill.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.99-103
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• 2006

Use of recycled fibers in papermaking has been increased for economical and environmental reasons. Recycled panels are major liber resources for brown grades and newsprints. Since the recycled fibers have disadvantageous properties as raw materials for papermaking it is of great importance to optimize the use of these recycled fibers. OCC (Old Corrugated Containers) is the major fiber source for linerboards and corrugating mediums that require diverse specification in strength properties. Many studies have been focused to overcome the problems of strength reduction of brown grades when recycled fibers are used as raw materials. The problem of strength loss for papers made from recycled fibers is closely associated with the increased amount of fines in recycled fibers and hornification of fibers. Fines contained in the recycled fiber resources cause problems not only in paper properties but also in process runnability. This shows that the optimal management and proper use of fines in recycling papermaking system are critical to get most benefits of using recycled fibers. In this study some approaches for optimal use of fiber fines in recycled paper mill have been investigated. Stock samples, prepared in the laboratory and obtained from a recycling plant were used. Fractionation of these samples was made using Sweco screen. And the effect of the addition of polyelectrolytes including cationic PAM and PEI on drainage and retention was evaluated. Different methods of polymer addition were compared to find the most effective ways of treating recycled fiber stocks with polyelectrolytes. Addition of polyelectrolytes to the short fiber fraction was most effective in retention and drainage. The influence of the charge and molecular weight of these two polymers has been examined and discussed.

• Computers and Concrete
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• v.21 no.6
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• pp.623-635
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• 2018

In order to research the influence of different recycled aggregate contents on the mechanical properties of pervious concrete, the experimental study and numerical simulation analysis of the mechanical properties of pervious concrete with five kinds of recycled aggregates contents (0%, 25%, 50%, 75% and 100%) are carried out in this paper. The experimental test were first performed on concrete specimens of different sizes in order to determine the influence of recycled aggregate on the compressive strength and splitting tensile strength, direct tension strength and bending strength. Then, the development of the internal cracks of pervious concrete under different working conditions is studied more intuitively by $PFC^{3D}$. The experimental results show that the concrete compressive strength, tensile strength and bending strength decrease with the increase of the recycled aggregate contents. This trend of reduction is not only related to the brittleness of recycled aggregate concrete, but also to the weak viscosity of recycled aggregate and cement paste. It is found that the fracture surface of pervious concrete with recycled aggregate is smoother than that of natural aggregate pervious concrete by $PFC^{3D}$, which means that the bridging effect is weakened in the stress transfer between the left and right sides of the crack. Through the analysis of the development of the internal cracks, the recycled aggregate concrete generated more cracks than the natural aggregate concrete, which means that the recycled aggregate concrete is easier to form a coalescence fracture surface and eventually break.

• Advances in materials Research
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• v.13 no.3
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• pp.173-181
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• 2024

Fly ash, plastic waste, and clay are mineral materials and residues commonly found in Malaysia. In this study, these materials were fully utilized as raw materials for synthesizing carbon nanotubes (CNTs). Recycled polypropylene, previously used as a food container, served as a carbon source. Fly ash and clay were explored as potential substrates for CNTs growth. The recycled polypropylene was thermally decomposed at 900 ℃ in an inert environment for 90 minutes. Carbon atoms released during this process were deposited on fly ash and clay substrates, which had been immersed in a ferrocene solution to provide a metal catalyst for CNTs growth. The deposited products were characterized using a Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD). Morphological analysis revealed that both fly ash and clay were coated with fiber-like structures, confirmed to be CNTs based on a diffraction peak around 26° from the XRD pattern. In conclusion, clay and fly ash demonstrate the potential to be utilized as substrates for CNTs formation.

• Magazine of RCR
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• v.5 no.3
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• pp.14-19
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• 2010