• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.1
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• pp.19-25
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• 2014

The purpose of this study is to establish experimentally the mechanical properties of fiber reinforced concrete using kenaf dosages and propose the usable method of kenaf fiber in the concrete industry as natural fiber materials. Kenaf fiber help make the concrete strength including tensile and flexural stronger, more resistant to plastic and drying shrinkage, less amount of carbon dioxide because of having a rough surface and excellent tensile strength of fiber and improving the concrete's corrosion resistance. It is to select the kenaf dosages of 4 cases (0, 0.3, 0.6 and $0.9kg/m^3$ and perform various tests including slump, air content, plastic and drying shrinkage, flexural and tensile strength for fiber reinforced concrete. The results of this study are as follows : In case of increasing kenaf fiber dosages, show the slump decrease and air content increase, also take effect results for increasing concrete strength including flexural and tensile, decreasing plastic and drying shrinkage. therefore, considered test results and cost, the optimum dosages of kenaf fiber is proposed about $0.6kg/m^3$ and need to study on the site application considering concrete quality and another compared tests.

• International Journal of Highway Engineering
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• v.19 no.6
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• pp.57-66
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• 2017

PURPOSES : This study develops eco-friendly asphalt reinforcement materials applicable to bridge deck pavement. The main purpose is to ensure highly reliable quality applicable to structures and the possibility of practical application. The main target of the study is to develop materials that are environmentally friendly and capable of improving performance. METHODS : The application of double-reinforcement fiber improves the performance of the road pavement. 1. We use recycled film for application of sheet-typed reinforcement. 2. We use preprocessing fibers to reinforce the properties of composite pavement materials. RESULTS : The developed products may produce materials that fit the purpose of achieving stability and environmental friendliness. Sheet-typed reinforcements use more than 50% recycled resin. The most important type of damage to the asphalt layer is deflection (plastic deformation). These products have a very high deflection resistance of not less than 6,000 cycles/mm. In addition, all performance is excellent. Thus, it will be easier to access the field in the future. CONCLUSIONS : Fiber-reinforced asphalt pavement showed excellent performance. Sheet-typed reinforcements containing 50% recycling resin produced good performance in terms of functionality as well as environmental friendliness. Thus, enhancing the field applicability will enhance the usability of the reinforcements.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.4
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• pp.82-90
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• 2009

It is very important to utilize effectively fibrous waste paper in terms of cost savings, environmental effects, and governmental policies. The quality of final products and runnability of papermaking process are primarily affected by constitutions of fibrous raw materials. In specific, board grade paper depends directly on compositions of waste paper bales. At present, the raw materials of board grade paper are mainly derived from lots kinds of wastepaper. Some papermaking countries, like EU, USA and Japan have advanced classification and management systems of recycled fiber, but Korea has not yet organized systematically. In this study, evaluation of wastepaper bale compositions and their fiber properties were carried out for effective utilization of fibrous raw materials for board grade paper production. 3 kinds of wastepaper bales were classified to fibrous or non-fibrous materials. In case of fibrous materials, KOCC, kraft sack paper and white duplex board matters were main component in total weight basis, and in case of non-fibrous materials, vinyl, plastic and cloth matters were main component, in turns. 3 representative kinds of waste paper were disintegrated and classified, and then prepared to handsheet for evaluation of recycled fiber property. Consequently, fines and ash content of waste paper, isolated from KOCC and white duplex board were higher than that of kraft sack paper. pH values of all kinds of waste fibers were neutral or weak alkaline.

• Smart Structures and Systems
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• v.22 no.4
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• pp.433-440
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• 2018

Pavements porous concrete is a noble structure design in the urban management development generally enabling water to be permeated within its structure. It has also capable in the same time to cater dynamic loading. During the technology development, the quality and quantity of waste materials have led to a waste disposal crisis. Using recycled materials (secondary) instead of virgin ones (primary) have reduced landfill pressure and extraction demanding. This study has reviewed the waste materials (Recycled crushed glass (RCG), Steel slag, Steel fiber, Tires, Plastics, Recycled asphalt) used in the pavement porous concretes and report their respective mechanical, durability and permeability functions. Waste material usage in the partial cement replacement will cause the concrete production cost to be reduced; also, the concretes' mechanical features have slightly affected to eliminate the disposal waste materials defects and to use cement in Portland cement (PC) production. While the cement has been replaced by different industrial wastes, the compressive strength, flexural strength, split tensile strength and different PC permeability mixes have depended on the waste materials' type applied in PC production.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.1
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• pp.53-59
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• 2013

Since 1990s, the major recycling methods for mechanical recycling of FRP(Fiber Reinforced Plastics)boats has involved shredding and grinding of the scrap FRP in a new recycled product. But still it leads to secondary problem such as air pollution, unacceptable shredding noise level and few limited applications. This study is to propose a newly advanced method which is more efficient and environment friendly waste FRP regenerating system. As extracting FRP layer and making the recycled fiber for recycled-fiber reinforced concrete(RFRC) from waste FRP, the recycling process has some merits in a sense of the recycling energy and the environmental effects. In this study, for those tasks, spectro-chemical differentiation method and coloring water-soluble dye treatment makes the roving layer more distinguishable photophysically. Also that has remarkably reduced safety hazards and energy. Using the mechanical properties of polymers and composite, FRP with the orthotropic and laminated plastic structure has been easily separated in the new extracting system. Also the new method has introduced five kind of separating manuals for the some different compositions of FRP boats. The roving fiber of laminated glass-fiber layer is as good as the polyvinyl fiber which is cost-high commercial fiber to increasing strength of concrete products. The early study has shown the effectiveness of laminated glass-fiber layer which also is chemical-resistant due to the resin coating. These results imply that more efficient and environment friendly recycled glass fiber can be better applied to the fiber reinforced concrete(FRC) substitute and this study also has shown wide concrete applications with RFRC from the waste FRP boat.

• Composites Research
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• v.28 no.4
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• pp.168-175
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• 2015

Recently, the applications of carbon fiber reinforced plastics (CFRPs) have become broader than ever when it comes to such industries as automotive, ships, aerospace and military because of their lightweight-ness and high mechanical properties. Thermosetting plastics like epoxy are frequently used as the binding matrix in CFRPs due to their high hardness, wetting characteristics and low viscosity. However, they cannot melted and remolded. For this reason, thermosetting plastic wastes have caused serious environmental problems with the production of fiber reinforced plastics. Thus, many studies have focused on the carbon fiber reinforced thermoplastics (CFRTPs) and recycling carbon fiber. In this study, recycled carbon fiber (RCF) was prepared from CFRPs using a pyrolysis method, which was employed to separate resin and carbon fiber. The degree of decomposition for epoxy resin was confirmed from thermal gravimetric analysis (TGA) and scanning electron microscope (SEM). The RCF was cut and ground to prepare a carbon fiber composite sheet (CFCS). CFCS was manufactured by applying recycled carbon fibers and various thermoplastic fibers. Various characterizations were performed, including morphological analyses of surface and cross-section, mechanical properties, and crystallization enthalpy of CFCS at different cooling conditions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5A
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• pp.543-550
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• 2009

This study was performed to prove the possibility of utilizing short plastic fibers made for recycled polyethylene terephthalate (RPET) as a structural material. In order to verify the capacity of RPET fiber, it was compared with polypropylene (PP) fiber, most widely used short synthetic fiber, for fiber volume fraction of 0%, 0.5%, 0.75%, and 1.0%. To measure material properties such as compressive strength, split tensile strength, appropriate tests were performed. Also, to measure the strength and ductility capacities of reinforced concrete (RC) member casted with RPET fiber added concrete, flexural test was performed on RC beams. The results showed that compressive strength decreased, as fiber volume fraction increased. These trends are similarly observed in the tests of PP fiber added concrete specimens. Split cylinder tensile strength of RPET fiber reinforced concrete increased slightly as fiber volume fraction increased. For structural member performance, ultimate strength, relative ductility and energy absorption of RPET added RC beam are significantly larger than OPC specimen. Also, the results showed that ultimate flexural strength and ductility both increased, as fiber volume fraction increased. These trends are similarly observed in the tests of PP fiber added concrete specimens. The study results indicate that RPET fiber can be used as an effective additional reinforcing material in concrete members.

• 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.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.3
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• pp.210-215
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• 2019

Concrete members with wide surface area are vulnerable to cracking due to material behavior such as hydration heat and drying shrinkage. Recently many researches have been performed on improvement of strength and cracking resistance through fiber reinforcement, which are mainly focused on enhancement of tensile strength against cracking due to material behavior. In this paper, CFs(Cellulous Fibers) are manufactured for slurry type, and the engineering properties in cement mortar incorporated with CFs are evaluated for flow-ability, compressive, and flexural strength. Through SEM analysis, a pull-off characteristics of CF in matrix are analyzed. With CF addition of $0.5kg/m^3{\sim}1.0kg/m^3$, flexural strength is much improved and enough toughness of pull-off is also observed unlike plastic fiber containing smooth surface.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.3
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• pp.177-183
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• 2023

Various failure modes occur in the concrete beams reinforced with GFRP(Glass Fiber Reinforced Plastic) under initial condition and repairing patterns. In this study, the failure behaviors of concrete beams restrengthened with GFRP sheet with slightly higher elastic modulus than concrete were investigated. For the tests, concrete beams with 24 MPa were manufactured, and the effects of initial notch, overlapping, end-strip reinforcement, and fiber anchors were analyzed on failure load. The cases of GFRP overlap around notch and the initial notch showed increasing failure loads similar to those of normal restrengthened case since the epoxy of the saturated GFRP sufficiently repaired the notch area. Compared to the control case without restrengthening of GFRP, the concrete with initial notch showed 0.78 of loading ratio and normal restrengthening showed 4.43~5.61 times of increasing ratio of failure loading, where interface-debonding from flexural crack were mainly observed. The most ideal failure behavior, break of GFRP, was observed when end-strip over 1/3 height from bottom and fiber anchor were installed, which showed increasing failure load over 150 % to normal restrengthening.