• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.2
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• pp.59-66
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• 2006

This study is performed to evaluate freezing and thawing properties of polypropylene fiber reinforced eco-concrete using soil, natural coarse aggregate, soil compound and polypropylene fiber. The mass loss ratio is decreased with increasing the content of natural coarse aggregate and soil compound, but it is increased with increasing the content of polypropylene fiber. The ultrasonic pulse velocity, dynamic modulus of elasticity and durability factor are increased with increasing the content of natural coarse aggregate and soil compound, but it is decreased with increasing the content of polypropylene fiber. The mass loss ratio, ultrasonic pulse velocity, dynamic modulus of elasticity and durability factor are $1.49{\sim}3.32%,\;1,870{\sim}2,465\;m/s,\;77X10^2{\sim}225X10^2\;MPa\;and\;84.6{\sim}92.8$ after freezing and thawing 300 cycles, respectively. These eco-concrete can be used for environment-friendly side walk and farm road.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.7
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• pp.11-19
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• 2003

In this study, unsaturated polyester resin, artificial lightweight coarse aggregate, artificial lightweight fine aggregate, heavy calcium carbonate and steel fiber were used to produce a steel fiber-reinforced lightweight polymer concrete with which mechanical properties were examined. Results of this experimental study showed that the flexural strength of unnotched steel fiber-reinforced lightweight polymer concrete increased from 8.61 to 13.96 MPa when mixing ratio of fiber content increased from 0 to 1.5%. Stress intensity factors($K_{IC}$) increased with increasing fiber content ratio while it did not increase with increasing notch ratio. Energy release rate ($G_{IC}$) turned out to depend upon the notch size, and it increased with increasing steel fiber content.

• Journal of the Korean Geotechnical Society
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• v.19 no.2
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• pp.189-197
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• 2003

In this paper, deformation characteristics of fiber-mixed-soils were studied at small strain range(0.0001%～1%) using resonant column test and triaxial test, and reinforcement effect was evaluated by the measure of maximum shear moduli. The effects of the major parameters such as fiber content, aspect ratio and fiber type on reinforcement were comparatively assessed. The specimens were remolded from Jumunjin Sand randomly mixed with discrete polypropylene staple fibers. Maximum shear moduli of fiber-mixed-soils increased by up to 30% and modulus reduction was also restrained in nonlinear range. Shear moduli increased as the aspect ratio increases. The reinforcement was more effective with fibrillated fiber than with monofilament fiber. The most effective reinforcement was achieved with the specimen of 0.3 % fiber content.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.5 s.248
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• pp.543-549
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• 2006

The bursting properties under various conditions were investigated to ascertain the optimum conditions to yield the best properties. Fiber aspect ratio (AR: length of fiber/diameter of fiber), interphase condition and fiber content were considered as variables which impact the bursting pressure, bulge constant, torsional rigidity ratio. The bursting pressure of reinforced rubber increases up to 8.73 times compared to the virgin material. The better interphase condition shows the higher bursting pressure at given AR and fiber content. The bulge constant and torsional rigidity highly decrease with increasing AR and better interphase condition at same fiber content. The bulge constant and torsional rigidity reveal the minimum of 11% and 0.6% of the matrix, respectively. The bursted shape after test shows the different patterns between unfilled and reinforced rubbers. The case of virgin rubber shows a radiating shape while that of reinforced rubber shows a fluctuating straight line. Overall, it was found that the fiber AR and interphase condition have an important effect on bursting properties.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.04a
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• pp.55-58
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• 2007

This study investigates the spatting properties of high strength concrete, $60\sim80MPa$ class, designed with diverse aspect ratios and fiber content of nylon(NY). Test showed that increase of fiber content and aspect ratio in concrete decreased the fluidity of fresh concrete, especially for 1580 and 3000 aspect ratio of fiber. As for the compressive and tensile strength, adding NY fiber did not significantly affect the values In the range of high strength. After completing the fire test, the specimens containing both 750 and 1000 aspect ratios of fiber protected the spatting occurrence even in 0.05vol.% of fiber content. This specimens indicated the residual compressive strength ratio at 37%, showing the most favorable value among other specimens. Therefore, it is demonstrated that to protect the spalling in high strength concrete considering the effective fluidity, strength and economic efficiency altogether, adding 0.05vol.% of NY fiber with 750 aspect ratio Is beneficial.

• Composites Research
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• v.13 no.3
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• pp.30-37
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• 2000

The dynamic properties of short-fiber reinforced Chloroprene rubber have been studied as functions of interphase conditions and fiber content. The loss factor generally decreased with fiber content and showed different patterns according to interphase conditions. The better interphase condition showed the lower loss modulus, $E_2$. Also, the dynamic ratio decreased with fiber content and rapidly decreased in the case of double coatings, i.e., model C. Therefore, the short-fiber reinforced rubber could have the better isolation in frequency ratio($\sqrt{2}$ min.) compared to frequency ratio($\sqrt{2}$ max.). And we have investigate the possibility of applying short-fiber reinforced rubber to automotive engine mount.

• Computers and Concrete
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• v.5 no.1
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• pp.21-36
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• 2008

Steel fiber reinforced concrete is increasingly used day by day in various structural applications. An extensive experimentation was carried out with w/cm ratio ranging from 0.25 to 0.40, and fiber content ranging from zero to1.5 percent by volume with an aspect ratio of 80 and silica fume replacement at 5%, 10% and 15%. The influence of steel fiber content in terms of fiber reinforcing index on the compressive strength of high-performance fiber reinforced concrete (HPFRC) with strength ranging from 45 85 MPa is presented. Based on the test results, equations are proposed using statistical methods to predict 28-day strength of HPFRC effecting the fiber addition in terms of fiber reinforcing index. A strength model proposed by modifying the mix design procedure, can utilize the optimum water content and efficiency factor of pozzolan. To examine the validity of the proposed strength model, the experimental results were compared with the values predicted by the model and the absolute variation obtained was within 5 percent.

• Journal of the Korean Geotechnical Society
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• v.16 no.6
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• pp.87-95
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• 2000

A series of consolidated undrained triaxial compression testes were performed to increase field applications of soil admixtures mixed with short fiber. Kaolin clay and three types of fiber were selected and auto cutter was used to obtain reliable length of fibers. Remolded soil specimens were tested for obtaining the basic data to be applied to the reinforcement of soft clay, embankment or barrier and clay liner of wastes landfill etc. Conversion equations from weight to volume of clay mixed with short fiber are introduced and relationships between fiber content and fiber concentration are derived. It is found that reinforcing effect by aspect ratio and mixing ratio of short fiber decreases as confining pressure increases. The best efficient reinforcing effect is given at the aspect ratio of 80~120 and the fiber content of 1.2%~2.4% and the fiber diameter of 0.27mm.

• Composites Research
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• v.20 no.5
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• pp.13-19
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• 2007

Fiber-reinforced thermoplastic composites not only approach almost near to the strength of thermosetting composite but also has excellent productivity, recycling property, and impact resistance, which are pointed as weaknesses of thermosetting composites. The study for strength calculation of one direction fiber-reinforced thermoplastic composites and the study measuring precisely fiber orientation distribution were presented. Need the systematic study for the data base that can predict mechanical properties of composite material and fiber orientation distribution by the fiber content ratio was not constructed. Therefore, this study was investigated what affect the fiber content ratio and fiber orientation distribution have on the strength of composites. Fiber-reinforced thermoplastic composites by changing fiber orientation distribution and the fiber content ratio were made. Tensile strength ratio of $0^{\circ}$ direction of fiber-reinforced composites increased being proportional the fiber content and fiber orientation function as change from isotropy(J=0) to anisotropy(J=1). But, tensile strength ratio of $90^{\circ}$ direction by separation of fiber filament decreased when tensile load is imposed fur width direction of reinforcement fiber length direction.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.6
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• pp.1023-1030
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• 2001

The tensile properties of short nylon6 fiber reinforced NR and SBR have been investigated as functions of diameter ratio(DR), interphase condition, fiber aspect ratio(AR), and fiber content. The short-fiber(DR=3 and AR=2) reinforced SBR did not show the dilution effect for all interphase conditions. And the short-fiber(DR=3 and AR=2) reinforced NR did not show the dilution effect except for the no-coating. The better interphase condition, the lower dilution effect at same DR. The tensile moduli are significantly improved due to fiber content and diameter ratio at same interphase condition. The pull-out force increased with the DR. The better interphase condition, the higher pull-out force at same DR. It is found that the DR and AR have an important effect on tensile properties.