• Fire Science and Engineering
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• v.25 no.5
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• pp.8-13
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• 2011

High strength concrete is the occurrence of explosive spalling associated with high temperature such as a fire. The spalling causes the sever reduction of the cross sectional area with the exposure of the reinforcing steel, which originates a problem in the structural behaviour. The purpose of this study is to investigate the mechanical properties of lightweight mortar using perlite and polypropylene fiber for fire protection covering material. For this purpose, selected test variables were the ratio of water to cement, the ratio of cement to perlite, contents of polypropylene fiber. As a result of this study, it has been found that addition of perlite and polypropylene fiber to mortar modifies its pore structure and reduces its density. And it has been found that a new lightweight mortar can be used in the fire protection covering material.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.928-934
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• 2008

Resently, Fiber Reinforced Concrete is used for not only preventing crack of concrete but also reinforcing general methods. Steel Fiber and PP(poly-propylene) Fiber are usually used as fiber reinforced materials. However, using these materials for shotcrete on Railway tunnel can cause some problems such as damage of pressure hose and shotcrete rebound. In addition, Steel fiber is an expensive material and it can cause safety problems during applying to shotcrete. PP Fiber can cause a problem in fiber balling during applying to shotcrete railway tunnel construction. A purpose of the research is applying a development of PET(Poly Etylene Terephtalate) fiber by recycling pet bottles to the shotcrete tunnel exposed to explosion spalling. To investigate the reinforcement effect of the PET fiber, some basic tests are accomplished to physical properties and explosion spalling by fire. As a result of the tests, a concrete mixing the PET fiber has stronger resistance effect in the explosion spalling by high temperature than another strong fiber concrete does, and that the former concrete is also equal or more effective on the result of the above tests to physical properties like compression and strain than the latter one is demonstrated.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.283-284
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• 2009

The purpose of this study is to investigate the spalling resistance of super high strength concrete with polypropylene(PP) fiber after 3 hours unstressed fire test. Tests have been carried out as a function of PP fiber quantity and concrete strength(100MPa, 150MPa). The results indicate that the spalling resistance will be achieved in suitable amount of PP fiber.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.423-430
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• 2005

Fire accidents in underground space may bring much loss of lives as well as properties and result in catastrophic disasters. This study aimed to manufacture the high-temperature furnace capable of simulating fire scenarios (RABT and RWS) and carry out the preliminary fire tests to evaluate fire-induced damage in underground structures. Specimens used in the fire tests were the concrete segments generally used in shield TBM tunnels. The simulated fire scenario was set to the RABT curve that is the most representative fire scenario in underground space. From the fire tests, the spalling was estimated to reach approximately 20cm from the surface exposed to fire. In addition, from the observation of core specimens obtained after fire tests, the deteriorated zone of unspalled specimens amounted to approximately 10cm from the surface of spalling.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.32-33
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• 2014

In this study, evaluation on weight loss properties of spalling control fiber with heating rates has been conducted. For evaluation of this study, 3types of organic fibers(Polyethylene, Polypropylene, Nylon) are used as spaling control fiber. Also, to evaluate the effect of heating rate to spallin control fiber, heating rates are set as 10, 25℃/min. As a result, the start time of weight loss of fiber with various heating rate was delayed as heating rate was increased.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.81-85
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• 2009

In the recent years, the high strength concrete has increasingly been used according to extending market of tall buildings. However, Ministry of Land, transport and Maritime Affairs was established by law with an alternative plan after June 2008 because of the weakness of high strength concrete accompanied spalling phenomena in fire. The mix design of concrete has to properly meet standards which are the spalling resistance of concrete and limited temperature of steel reinforcement. The fire proof concrete mixed fiber has widely been used to meet spalling safety on the many construction sites, the most researches about the fire proof concrete mixed fiber had being carried out focused on fire resistance, compressive strength and cast in place of concrete. But the most important thing is column shortening used the fire proof concrete within the vertical members. In this paper, the fire proof concrete filled spalling safety standards was experimented by required material when the column shortening is revised between normal concrete and fire proof concrete mixed fiber and then the results have done a comparative analysis. Also, The paper aimed to indicate a basic data for revision of column shortening of fire proof concrete.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.2
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• pp.100-106
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• 2014

High strength concrete has a structural advantage as well as superior usability and durability, so that its application in building is being steadily augmented. However, in the high temperature like in a fire, the high strength concrete has extreme danger named explosive spalling. It is known that the major cause of explosive spalling is water vapour pressure inside concrete. General solution for preventing concrete from spalling include applying fire protection coats to concrete in order to control the rising temperature of members in case of fire. The purpose of this study is to investigate the high temperature properties of fireproof mortar using organic fiber and various types of fine aggregate for fire protection covering material. The results showed that addition of perlite and polypropylene fiber to mortar modifies its pore structure and reduces its density. This causes the internal temperature to rise. As a results, it is found that a new fireproof mortar can be used in the fire protection covering material in high strength concrete.

• Journal of the Korea Institute of Building Construction
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• v.12 no.2
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• pp.183-193
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• 2012

Compressive property of high strength concrete with amorphous metal fibers subject to high temperature has been investigated. The measure of this investigation includes explosive spalling, weight loss, residual compressive strength, strain at peak stress, elastic modulus, and residual energy absorption capacity after exposure to $400^{\circ}C$, $600^{\circ}C$and $800^{\circ}C$. In addition to the amorphous metal fiber, two other types of fibers (polypropylene fiber and hooked-end steel fiber) were also included in this investigation for comparison. The experimental program was conducted with high strength concrete using several combinations of the fiber types. The testing result shows that the concrete with amorphous metal fibers plus polypropylene fibers shows a superior behavior than those using other combination or single fiber type ingredient.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.481-484
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• 2006

This study investigates the engineering and fire endurance properties of ultra high strength concrete. The mixture proportions with water to binder ratios (W/B) of 0.15 and 0.25 consist of various adding ratios, such as 0, 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3 percent respectively, of polypropylene (PP) fiber. As for the parameters of specimens, fluidity, compressive strength and unloading fire test were carried out. Test showed that an increase of fiber contents had the favorable properties in fire endurance performance; specimens in W/B 15% required 0.3vol% of PP fiber and specimens in W/B 25% needed only 0.1vol% to prevent spalling.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.11a
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• pp.19-22
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• 2007

This study discussed the prevention of the spalling and improvement of the fire resistance performance how to fill up lightweight foamed concrete on high strength RC column attached with the stone panel. The destructive spalling extremely occur caused by sudden high temperature and increased vapor pressure corresponding to falling the ston panel at all RC column, and the steel bar is exposed. The stone panel fall off about 30 minutes and spalling occur about 70 minutes on Plan RC column, fire endurance paint, and fire endurance mortar, so it can be confirmed that fire endurance paint and mortar, which is used as fire endurance material, are not effective. In the other side, it can be protected from fire about $120{\sim}140$ minutes when the lightweight foamed concrete is used as fire endurance material. For the weight loss after the fire test, plain is 33, fire endurance paint is 37%, and fire endurance mortar s 40.7%. And W/B 60%-3 is 53.4%, 60%-1.5 is 40.1%,65%-3 is 39.4%, and 65%-1.5% is 47.1. Overall, the weight loss of the plain is lower than that of the lightweight foamed concrete.