• Resources Recycling
• /
• v.24 no.3
• /
• pp.66-75
• /
• 2015

The flexural performance of amorphous steel fibers having environmental and economy benefits due to relatively short manufacturing process were evaluated as well as that of hooked steel fibers by varing fiber length and volume fraction. Fiber lengths were 10 mm, 20 mm, 30 mm and fiber volume fractions were varied from 0.3% to 1.2%. Test results with flexural performance showed that mixing design needs to be careful because of relatively high volume of amorphous steel fiber compared to hooked steel fibers. High flexural strength was obtained from both longer fiber length and higher volume fraction. Residual strength and toughness of amorphous steel fiber were similar to that of hooked steel fiber, even though rapid dropping of applied load right after concrete matrix breaking. It can be judged that relatively high ability of energy dissipation around first cracking area relatively overcome rapid dropping of loading.

• Resources Recycling
• /
• v.24 no.6
• /
• pp.61-68
• /
• 2015

In this study, the strength properties of NHL based mortar with blending basalt fiber were investigated. In the first step, it was evaluated that physical properties of NHL based mortar according to mixing method of four types of basalt fiber and then mixing method of one type was selected. As a result of assessment, it showed that the physical properties with mixing method of dry blending were better than that of wet blending and mixing method that basalt fiber pre-mixed with NHL for 5 min in a blender was selected and water and aggregate were finally added. Secondly, the investigation of blending fiber length on the compressive and flexural strength for basalt fiber reinforced NHL based mortars was carried out. The compressive strength was decreased with adding fiber, and the flexural strength was increased more than plain mortar. In the case of adding 6 mm fiber, the compressive and flexural strength were improved more than that of others.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2009.05a
• /
• pp.543-544
• /
• 2009

The fiber(NY, PP) known to the effective material on improvement of the fire-resistance of HSC(high strength concrete) has a difference for fluidity according to the variation of a length and contents of fiber. In this study, to analyze the effect of a length and contents of the fiber on the fluidity of HSC and fheological characteristics, we calculated a viscosity of mortar by mini slump-flow, simple V-lot and viscometer. With the test results, the fluidity characteristic showed a moderate difference by a length and contents of the fiber, but showed a significant difference by increase of the fiber contents. ${\ast}$ AFR Concrete (Advenced Fire Resistant Concrete)

• Applied Chemistry for Engineering
• /
• v.27 no.3
• /
• pp.270-275
• /
• 2016

High density polyethylene (HDPE)/kenaf fiber (KF) composites included two types of KF with different lengths were fabricated by using a twin screw extruder. A thermally expandable microcapsule (EMC) was used to form HDPE/KF. The KF lengths were 0.3 mm and 3 mm. The contents of KF and EMC were fixed at 20 wt% and 5 wt%, respectively. From FT-IR data of KF, which underwent chemical treatment, peaks around 1700 and $1300cm^{-1}$ decreased. This might be caused by the reduction of lignin and hemicellulose due to the chemical treatment of KF. Based on the specific gravity, thermal stability and tensile property, physical properties of the composites with a 3 mm fiber were good. However, if the fiber is longer, poor appearance might be caused due to the thermal degradation during processing. Thus, the adequate length of KF should be chosen to maintain the appearance and physical properties for industrial applications of HDPE/KF/EMC composites. The tensile strength for 0.3 mm fiber treated with chemicals increased slightly.

• Korean Journal of Materials Research
• /
• v.3 no.3
• /
• pp.292-299
• /
• 1993

In this paper the effects of the length of carbon fiber on the wear properties of carboni carbon composites were investigated. Carbon/carbon composites were fabricated by the liquid impregnation method using the resol-type phenolic resin as a matrix precursor and PAN-based, non-surface treated carbon fiber as a reinforcement. The measured values of the friction coefficient of carbon/carbon composites against AlSl 304 stainless steel ranged from 0.2 to 0.3 under the operating condition used in this study. The effect of the length of carbon fiber on the friction coefficient of carbon/carbon composites were not found. But, it was realized that the wear rate of carbon/carbon composites tends to increase, as the length of carbon fiber increases.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.2 no.3
• /
• pp.225-232
• /
• 2014

This paper concerns the mechanical properties of recycled plastic fiber-reinforced concrete. It presents experimental research results of recycled fiber-reinforced concrete with fiber volume fractions of 0, 0.5, 1.0, 1.5, and 2%. Experiments were performed to measure mechanical properties such as compressive strength, elastic modulus, tensile strength, and length changes. The results show that both compressive strength and elastic modulus decreased as fiber volume fraction increased. In addition, the experimental results show that recycled fiber-reinforced concrete is in favor of split tensile strength, flexural tensile strength, characteristic regarding crack mouth opening displacement, and length changes. The results of this study can be used to provide realistic information for modeling of mechanical properties in recycled plastic fiber-reinforced concrete in the future.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.12
• /
• pp.697-704
• /
• 2017

High-Performance Fiber-Reinforced Cement Composites (HPFRCC) has outstanding durability, and has attracted interest because of its ductility and development of strength, which allows a reduction of the self-weight of a structural member by substantially decreasing the cross section. Therefore, the present study aimed to improve the economic efficiency of HPFRCC by examining experimentally the flexural performance considering various characteristics of the steel fiber. To find an efficient fiber reinforcement method, the flexural performance was evaluated for different shapes, aspect ratios, and volume ratios of the steel fiber. Straight, hooked, and twisted fiber configurations were considered by adopting a fiber length longer than the usual 13 mm. The test results showed that HPFRCC reinforced by 19.5 nun-long straight fibers with a volume fraction of 1.5% shows better flexural performance than that reinforced by 13 mm-long straight fibers with a volume fraction of 2.0%. Consequently, HPFRCC with enhanced economic efficiency can be produced by adopting a reduced amount of steel fiber.

• Journal of the Korea Concrete Institute
• /
• v.22 no.5
• /
• pp.651-658
• /
• 2010

Sixteen concrete mixes reinforced with hybrid steel-polybinyl alcohol (PVA) fibers and a control concrete mix with no fiber were tested in order to examine the effect of the micro and macro fibers on the slump and different mechanical properties of concrete. Main variables investigated were length and volume fraction of steel and PVA fibers. The measured mechanical properties of hybrid fiber reinforced concrete were analyzed using the fiber reinforcing index and compared with those recorded from monolithic steel or PVA fiber reinforced concrete. The initial slump of hybrid fiber reinforced concrete decreased with the increase of the aspect ratio and the volume fraction of fibers. In addition, splitting tensile strength, modui of rupture and elasticity, and flexural toughness index of concrete increased with the increase of the fiber reinforcement index. Modulus of rupture and flexural toughness index of hybrid fiber reinforced concrete were higher than those of monolithic fiber reinforced concrete, though the total volume fraction of hybrid fibers was lower than that of monolithic fiber. For enhancing the flexural toughness index of hybrid fiber reinforced concrete, using the steel fiber of 60 mm length was more effective than using the steel fibers combined with 60 mm and 30 mm lengths.

• Proceedings of the Korean Fiber Society Conference
• /
• 1998.04a
• /
• pp.249-252
• /
• 1998

니들펀칭 부직포는 구성 섬유소 집합체(web)를 바늘에 펀칭시켜 통과시킴으로써 섬유소간의 물리적인 결합력을 이용하여 제작한 섬유 구조물을 말한다. 니들펀칭 부직포의 물성에 미치는 인자는 크게 다음 세가지라고 볼 수 있다. 첫째, web을 구성하는 섬유의 물성이다.[1-4] 즉, 구성섬유의 인장성질이나 단면의 모양, 크림프의 존재유무, 섬도, 섬유길이, 마찰특성들이 부직포의 물성에 직접적인 영향을 준다.(중략)

• Journal of the Korea Institute of Building Construction
• /
• v.8 no.1
• /
• pp.43-48
• /
• 2008

Fifteen concrete specimens were mixed and tested to explore the significance and limitation of appling the polyvinyl alcohol (PVA) fiber and steel fiber with end hook to concrete. Main parameters investigated were volume fraction and length of the fibers. The measured mechanical properties of fiber reinforced concrete are analyzed according to the equivalent fiber amount index explaining the adding amount and length of fibers. Test results showed that compressive strength of fiber reinforced concrete was higher than that of concrete with no fiber by $10{\sim}20%$. The normalized splitting tensile strength and flexural strength of PVA fiber reinforced concrete were similar to those of concrete with no fiber, whereas those of steel fiber reinforced concrete increased with the increase of the equivalent fiber amount index. In particular, much higher ductile behavior was observed in steel fiber reinforced concrete than in PVA reinforced concrete, indicating that the slope of descending branch of load-displacement relationship of steel fiber reinforced concrete decreased with the increase of the volume fraction and length of the fiber.