• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2006.04a
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• pp.172-175
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• 2006

Recently, fire resistance of high performance concrete for explosive spatting was issued as high performance concrete was vulnerable to the explosive spatting in initial fire. Therefore, This study is willing to propose fundamental data for quick and accurate diagnosis of deteriorated concrete structure by fire damage with making variable concrete test specimen, exposing high temperature environment, observing the explosive spatting and examining engineering property.

• Fire Science and Engineering
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• v.21 no.2 s.66
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• pp.54-63
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• 2007

Concrete is generally accepted to have good inherent fire resistance. It mainly relies on the assumption that concrete has low heat-transfer characteristic and spatting does not occur during the course of a fire. However, the significant numbers of fire accidents have shown in recent years that incidence of spatting has caused sever damages to many structures. This review has systematically investigated the behaviour of concrete in fire, including phenomenon of spatting, with respect to the theorical consideration and experimental results. Explosive spatting is caused by the build-up of water vapor pressure in concrete subjected to increasing temperatures. When this pressure exceeds the tensile strength of the concrete over a fire-exposed area, explosive spatting can result in a typical temperature range between $200^{\circ}C\;and\;400^{\circ}C$. The major functions are known to be moisture content, pore pressure, load ratio, and heating regime.

• Fire Science and Engineering
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• v.18 no.1
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• pp.31-36
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• 2004

The purpose of this study is to present data for the reusing, rehabilitation and estimation of safety of RC structure damaged by fire, and for the prevention of explosive spatting by investigation the properties of explosive spalling, compressive strength and ultrasonic pulse velocity according to kinds of fine aggregate, admixture and water-cement ratios. In explosive spalling properties with kinds of aggregate, explosive spalling does not appear or little at surface in the case of used sea sand, but the case of using recycled sand or crushed sand is worse and worse. Property with the kind of admixture does not appear specially. And high strength concrete with W/C 30.5% was taken spalling, but 55% does not appear. It is found that residual compressive strength after exposed at high temperature showed 45％ in W/C 55%, and 64％ in W/C 30.5％ of its original strength averagely. Ultrasonic pulse velocity is different with kinds of aggregate. W/C. and heating time. When 3 month age after heating ultrasonic pulse velocity is recovered abut 1.3％～8.4％ of its 1 month age after heating.

• Magazine of the Korea Concrete Institute
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• v.17 no.3 s.86
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• pp.20-25
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• 2005

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2007.04a
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• pp.89-94
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• 2007

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.199-203
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• 2008

With recent trend in domestic and global market requiring architectures' conversion into skyscrapers seasoned with the features of landmarks, structural problems in relation with explosive spatting during fire emergencies are arising as controversial issues. Accordingly, many productive researches have been made in relation to the reinforcement techniques for improving fire resistance and the number of applications in the field is gradually increasing. In this study, a ductile outline form using ECC (Engineered Cementations Composites) was made with improvements on the structure and fire resistance to examine its applicability. Also, currently in Japan, the number of studies and applications is increasing focusing on reduction of construction time and improvement of workability with application of Half-PCa method. However, using such method of construction, large structural members decrease the utilization of space and architecture-wise, there is a disadvantage of the weight increase. Therefore, in such context, it would be worth reducing the weight of the structural members by reducing the size using ECC. In addition, its excellent pseudo strain-hardening due to fiber may have great effects on seismic designs. In the mean time, this study planned 3 equal conditions for mix water, PVA fiber and additives excluding binder and refractory to evaluate the mechanical properties of resistance against pressure and internal force. Finally, an evaluation was executed on the fire resistance of the newly made ductile outline form. As a result, from ECC-I to ECC-III, all showed excellent mechanical properties due to pseudo strain-hardening and in the fire resistance test conducted with ISO 834 heating curve, most of them tended to be in the range of the reference temperature (538℃-180min), so there was no occurrence of any explosive spatting.

• Fire Science and Engineering
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• v.18 no.3
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• pp.51-56
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• 2004

A fire outbreak in a reinforcement concrete structure looses the organism by the different contraction and expansion of hardened cement pastes and aggregate, and causes cracks by thermal stress, leading to the deterioration of the durability. So concrete reinforcement structure is damaged partial or whole structure system. Therefore diagnosis of deterioration is needed based on mechanism of fire deterioration in general concrete structures. Fundamental information and data on the properties of concrete exposed to high temperature are necessary for accurate diagnosis of deterioration. In this study, it was presented data for the accurate diagnosis and selection of repair and reinforcement system for the deteriorated concrete heated highly, various concrete such as standard design compressive strength, fine aggregate and admixture were exposed to a high temperature environment. And fundamental data were measured engineering properties such as explosive spatting, ultrasonic pulse velocity and compressive strength.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.165-169
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• 2005

The fire damage of building wouid effect on the safety of structure. When the reinforced concrete structure is heated by high temperature due to the fire, the structural resisting-force will be decreased. In a way, it is a requirement to use high strength concrete for high rise building. Particularly, fire resistance properties of high-strength concrete is more important than normal strength concretes. The fire outbreak of a high strength concrete by sudden temperature rise is a main problem, and causes crack by thermal stress, loading to the deterioration of the durability. In this study, normal and high strength mortar were exposed to a high temperature environment. And than fundamental data for the character change of concrete heated highly were presented by measuring compressive strength of concrete with polypropylene and vinylon fiber, before and after heating. As the results, it is proven that high strength mortar with polypropylene and vinylon fiber for prevents deterioration of durability by fiber.