• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.153-156
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• 2009

This study investigated the fundamental properties corresponding to various length changes on NY fiber reinforced concrete. For results of fresh concrete, the slump and air content were declined, but the unit volume weight and vebe time were increased. For the hardened concrete properties, the compressive strength showed increasing tendency according to the NY fiber length. The dry and autogenous shrinkage also decreased compared with Plain. Generally, the caes that 19 mm NY fiber was used was better than any other cases.

• Journal of the Korea Institute of Building Construction
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• v.7 no.3
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• pp.83-90
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• 2007

This study is to investigate the effects of nylon(NY) and cellulose(CEL) fiber contents on the mechanical properties of the concrete. The results were summarized as following. Test showed that increase of NY and CEL fiber contents decreased fluidity of fresh concrete, so the loss of the fluidity would be considered when they were over added. Air contents were slight increased, but they satisfied the target air content. Bleeding capacity of concrete containing fiber significantly was declined. In addition, concrete containing higher amounts of fiber retarded setting time remarkably. Plastic shrinkage crack was reduced with the use of fiber due to increasing fiber contents and changing fiber classes, and NY fibers to prevent the plastic shrinkage crack effectively. Compressive and tensile strength of almost specimens were increased when air contents of the fresh concrete were fixed according to fiber contents, and flexural strength was increased according to fiber contents. For the impact strength of specimens, the specimen containing $0.6kg/m^3$ of NY fibers, showed the most favorable impact strength, The fiber reinforced concrete using NY fibers exhibited superior mechanical performance, and it was considered that $0.6kg/m^3$ of was desirable as the most favorable adding amount.

• Journal of the Korea Concrete Institute
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• v.22 no.4
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• pp.473-479
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• 2010

The objective of the paper is to experimentally investigate the effect of commercially avaliable fiber types such as polypropylene (PP), nylon (NY), polyvinyl alcohol (PVA) and cellulose (CL) on the engineering properties of concrete for pavement application. The results, showed the fluidity tends to decrease with fibers addition compared to that of plain concrete. As for the effect of fiber types on fluidity loss, use of NY appear to give the most favorable results among all of the fiber types investigated in this study while the effect of the fibers on air content was negligible. For the properties of hardened concrete, compressive and flexural strengths increased with fibers compared to plain concrete. The contribution of NY fibers to strength was the highest followed in the order by NY, PVA, PP, and CL. However, in the case of the splitting tensile strength, its values were increased with NY and PP only. For porosity based on MIP(mercury intrusion penetration) method, the number of around 1 was observed when NY was mixed resulting in increased cumulated amounts of porosity compared with that of plain mix. Thus, based on the consideration of fluidity and strength it was found that the addition of NY fiber showed the optimal results under the conditions applied in this study.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.51-54
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• 2009

In this study, the fire resistance test was carried out with a parameter such as fiber(PP+NY) mixed ratio on high strength concrete with 80MPa, and the spalling resistance property was evaluated. Concrete material test was carried out with a parameter such as fiber(PP+NY) mixed ratio(0%, 0.05%, 0.1%, 0.2%) of high strength concrete with 80MPa. Although the flowability and the strength capacity were delicately decreased with a increase of fiber mixed ratio, they satisfied the target limits. As the spalling resistance property after the fire resistance test of 3 hours, the spalling was partly shown on the high strength concrete with fiber(PP+NY) mixed ratio of 0% but, wasn't shown on the high strength concrete with fiber(PP+NY) mixed ratio of 0.05% ~ 0.2%.

• Journal of the Korea Institute of Building Construction
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• v.8 no.5
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• pp.101-107
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• 2008

This study investigated fundamental characters of the concrete according to various fiber types and contents and their properties of spatting resistance and residual compressive strength after fire test corresponding to ISO and RABT heating corves. The results were summarized as following. The Flowability was gradually declined as the increase of fiber contents, and it was the most favorable with nylon(NY) fibers. The decrease of air contents due to increasing fiber contents was in order by polypropylene(PP), polyvinyl alcohol(PVA) and NY fibers. The compressive strengths were over 40 MPa at 7 days and 50 MPa at 28 days. It was in order by PVA, PP and NY fibers. For the spatting properties, all specimens were prevented at ISO heating curve. In the other hand, the partial spatting at the surface occurred on the plain without fibers, but it was prevented over 0.10 % of PVA and 0.05 % of PP and NY fibers at the RABT heating curve.

• 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.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.05a
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• pp.87-91
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• 2008

The study examined fire resistance of concrete followed by change of mixed rate in PP and NY composite fiber and the results were as follows. In the event of fluidity in concrete not set, plane satisfied 600±100, its target slump flow, and fluidity was reduced as organic fiber's mixed rate was increased. Air amount satisfied 3.0±1.0, its target air amount, and didn't have distinct differences in reduction and increase according to organic fiber's kind and change of its mixed rate. However, it had a tendency that fluidity was reduced as the mixed rate was increased. In characteristics of hardening concrete, the 28th day compressive strength followed by organic fiber's kind and change of its mixed rate didn't have a lot of differences and satisfied high strength scope as about 70MPa. In spalling characteristics after fire resistance test, spalling was happened in non-mixture, plane combination, and P1N0. In other combinations, spalling resistance was happened. The relic compressive strength rate was 56%, the best condition, in P3N1(PP0.03%, NY0.01% compositeness) mixing PP fiber with NY fiber at once.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.11a
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• pp.95-98
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• 2007

This study investigates the mechanical properties of the high strength concrete in the region of 80MPa corresponding to the temperature and fiber content change. For the properties of the fresh, slump flow is $600{\pm}100mm$, and air content is $3.0{\pm}1.0%$. They satisfy each targets, and there was no difference for the each fiber types. As the propertied of the hardened concrete, the compressive strength at 28 days is indicated over 80MPa, and they are similar to the change of the fiber types. The residual compressive strength in response to the temperature change of the NY, PP, and NY+PP fiber at $200^{\circ}C$ are increased by 115, 114, and 110% on the standard condition, and it is suddenly decreased at $400^{\circ}C$. They are decreased by 33, 19, and 16% on the standard condition at $800^{\circ}C$.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.137-140
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• 2009

Nowadays, the high performance composite materials are famous for the new construction materials as the construction buildings are bigger and higher. Out of them of all, the fiber reinforced concrete and mortar have been studied to develop and strengthen the performances of concrete, such as tensile strength, durability and the resistibility of crack. Also, it is considered that precast concrete is important alternatives of dry process for saving time, upgrading the material's quality and the productivity. Thus, PC panel is being produced for the use of dry wall as well as exterior finishing materials and it requires lots of tests and studies to be conducted to meet the various functional conditions. According to this study, it is considered that PVA fiber might be more effective than nylon fiber for developing the exterior PC panels.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.417-418
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• 2010

The purpose of this study is to investigate the fire resistance of high strength concrete with fiber after 3 hours unstressed fire test. Two types of fiber, polypropylene(PP) and Nylon(NY), were selected, and three cover thickness were selected, which were 40mm, 50mm, 60mm. The results indicate that the fire resistance will be achieved in suitable amount of fiber.