• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.734-737
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• 2004

The synthetic fibers such as polypropylene(PP) and polyvilyl-alcohol(PVA) fiber are poised as a low cost alternative for reinforcement in structural applications. It has been reported that synthetic fiber in cement composites can control restrained tensile stresses and cracks and increase toughness, resistance to impact, corrosion, fatigue and durability. High performance fiber reinforced cementitious composite(HPFRCCs) shows ultra high ductile behavior in the hardened state, because of the fiber bridging properties. Therefore, a variety of experiments have being performed to access the performance of HPFRCCs recently. The research emphasis is on the flexural behavior of HPFRCCs made in synthetic fibers, and how this affects the composite property, and ultimately its strain-hardening performance. Three-point bending tests on HPFECCs are carried out. As the result of the bending tests, HPFRCCs showed high flexural strength and ductility. HPFRCCs made in PVA or Hybrid fiber were, also, superior to PP of singleness. On the other hand, effect of sand volume fraction on HPFRCCs made in PP was insignificant.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.11a
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• pp.95-98
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• 2006

This study investigates spalling properties of high performance concrete, 60MPa clan, made with the various types of coarse aggregate and adding ratio of polypropylene(PP) fiber. As experimental parameters, totally sixteen specimens of ${\phi}100{\times}200mm$ in size are prepared: one specimen for control without fiber, ten specimens with different coarse aggregate types, along with 0.05, 0.1, 0.15 percent of PP fiber in each. 1 hour fire test is conducted and then spalling appearance, spalling degree and residual compressive strength are examined. In addition, sit specimens made with two types of coarse aggregate site, along with same adding ratio of fiber are supplementally done, and only spalling properties is examined. Test results showed that control concrete and most specimens containing 0.05% of PP fiber exhibited 4 to 3 level of spalling degree, resulting severe explosive spalling, except for the specimen using basalt aggregate(Bc) showing 2 to 3 level of that. Especially, the Bc specimen containing 0.1% of the fiber exhibited that residual compressive strength value was 32%, which is 10% higher than other specimens using limestone or granite. Spalling resistance performance was also effective as aggregate size increase.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.187-191
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• 2008

It is necessary to develop a technology for effectively controling explosive spalling of high strength concrete caused increasing construction of high rise building and putting up the fireproof standard of high strength concrete by MLTM (Ministry of Land, Transport and Maritime Affairs). Accordingly, it was investigated basic properties such as slump, air content and compressive strength, and fire resistance properties of high strength concrete using polypropylene fiber for field application as a countermeasure for explosive spalling of concrete on fire in this study, As a test result, it was confirmed that PP fiber is available as fire resistance method of high strength concrete.

• Composites Research
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• v.26 no.1
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• pp.48-53
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• 2013

This paper summarizes the structural characterization of borassus fruit fibers by means of various characterization techniques, optimization of alkali treatment of borassus fruit fine fibers (BFF) with a 5% concentration sodium hydroxide solution for different time intervals (1, 4, 8 and 12 h) and the changes occurring in borassus fibers. This paper also discusses the manufacturing of BFF/PP compotes using MAPP as a compatibilizer in addition to alkali treatment. Composites were evaluated for their mechanical and morphological properties. The tensile strength and modulus, flexural strength and modulus and impact strength were increased for alkali treated/MAPP composites by 4.5%, 17%, 17.2 %, 9% and 10% respectively.

• Journal of the Korea Institute of Building Construction
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• v.10 no.4
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• pp.3-9
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• 2010

Fire resistance and material properties of high-strength concrete (W/B 21.5%, 28.5%) with OPC, BS and FA were tested in this study. Main factors of the test consisted of fiber mixing ratio and W/B. Two types of fiber (NY, PP) mixed with the same weight were used for the test. The fiber mixing ratios were 0%, 0.05%, 0.1%, and 0.2% of the concrete weight. After performing the test, Under the W/B level of 21.5% and 28.5%, the spalling was effectively resisted by using the high strength concrete with fiber mixing ratios of 0.05%~0.1%. Compressive strength, flowability and air content are similar those of the fiberless high-strength concrete with the same W/B.

• Membrane and Water Treatment
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• v.11 no.3
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• pp.231-235
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• 2020

Industrialization and modern developments have led to an influx of toxic heavy metals into the aquatic environment, and the accumulation of heavy metals has serious adverse effects on humans. Among the various heavy metal treatment methods, adsorption is very useful and frequently used. Plastic materials, such as polypropylene and polyethylene, have been widely used as filter media due to their mechanical and chemical stability. However, the surface of plastic material is inert and therefore the adsorption capability of heavy metals is very limited. In this study, granular media and fiber media composed of polypropylene and polyethylene are used, and the surface modification was conducted in order to increase adsorption capability toward heavy metals. Oxygen plasma generated hydroxyl groups on the surface of the media to activate the surface, and then acrylic acid was synthesized on the surface. The grafted carboxyl group was confirmed by FT-IR and SEM. Heavy metal adsorption capability of pristine and surface modified adsorbents was also evaluated. Overall, heavy metal adsorption capability was increased by surface modification due to electrostatic interaction between the carboxyl groups and heavy metal ions. Fibrous PP/PE showed lower improvement compared to granular PP media because pore blockage occurred by the surface modification step, thereby inhibiting mass transfer.

• Journal of the Society of Disaster Information
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• v.7 no.1
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• pp.43-50
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• 2011

The Application of Steel Fiber Shotcrete in tunneling construction has become part of tunneling practice at least since the 1970s because of its high bending and tensile properties. Over the past 3 decades, researcher from all over the world have been significantly developing the associated technologies for improved performance of SFRS. But still it has some major drawbacks in terms of durability, damage of pumping hose, wastage due to rebound concrete, corrosion and it costs high. To overcome this situation researcher has to look for some alternative material. Therefore, this part study deals with the three types of fiber in order to find good alternative for steel fiber. Polyamide and Polypropylene fiber were used in this study with 0.6, 0.5% mixing ratio. To evaluate its fresh and harden properties air content, slump, compressive, split tensile and bending strength were measured. After comparing the results of all three types of fiber reinforced concrete with its different mixing proportion this study propose that polyamide fiber with addition ratio of 0.6 % for field use.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.65-68
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• 2006

This study is aimed to investigate the strength variation of fire-damaged reinforced concrete column with polypropylene by non-destructive test. It is studied to infer the recovery degree of residual strength of fire-damaged concrete. For measuring the surface hardness of RC columns, Schmidt hammer test is used. Testing is performed four-times: before fire test, directly after fire test, after 30 days and after 4 months.

• Composites Research
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• v.20 no.1
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• pp.23-31
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• 2007

In order to improve the mechanical properties of jute fiber/polypropylene(PP) composites, the property change with the addition of a coupling agent, maleic anhydride polypropylene(MAPP) was examined experimentally. The maleated coupler acts as an intermediate to chemically connect the polar nature of the fiber and non-polar nature of the polyolefin polymer resin. Furthermore, the decrease in viscosity of the resin which results from the melting point reduction by the MAPP, leads to an increase of contact area with the fiber interface. We discussed the improvement of the PP composite blend of the maleated coupler with the 80mm jute long fiber mat in conjunction with the change of physical parameters in the thermoplastic resin. We confirmed the extent of contribution to the mechanical physical enhancement by using the following parameters: melting flow index(MI) and viscosity, contact angle, thickness of the composite, interfacial shear strength and morphology observation etc. Especially it was observed that the MI and viscosity, MAPP mixture had a very strong relationship with the tensile and flexural strength and modulus, and interfacial shear strength(IFSS).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.8-14
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• 2015

Plastics have brought a significant progress in reducing the weight of automotive parts and improving gas emissions by replacing steel parts. The front end module (FEM) carrier, which was made from long glass fiber reinforced polypropylene (PP-LFT), is one of the most successful examples. On the other hand, more research on the fatigue behavior and vibration durability of automotive plastic parts will be needed to improve the long-term reliability. This paper analyzed the durability of the PP-LFT, which is fundamental to fatigue design and analysis of FEM carrier. Various fatigue tests were conducted at different stress ratios to evaluate the relationship between the fatigue life and stress amplitude or mean stress level. In the case of a fixed stress amplitude, the change in fatigue life with the stress ratio was 2~6% larger than the case of fixed maximum stress. Furthermore, this study observed the mechanism of initiation and propagation of the fatigue cracks in PP-LFT by scanning electron microscopy.