• Journal of the Society of Disaster Information
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• v.7 no.4
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• pp.286-293
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• 2011

Accordingly architectural structure is getting high-rise and bigger, a use of high strength and high performance concrete has been increased. High performance concrete has cons of explosion in a fire. This explosion in the fire can cause the loss of the sheath on a concrete surface, therefore it effects that increasing a rate of heat transmission between the steel bar and inner concrete. Preventing this explosion of high performance concrete in the fire, many kinds of researches are now in progressing. Typically, researches with using polypropylene-fiber and steel-fiber can prove controling the explosion, but the reduction of mobility was posed as a problem of workability. Consequently, to solve the problem as mentioned above, concrete cans secure fire resisting capacity through the using of coating liquid, including Ester-lubricant and non-ionic characteristic surfactant. This research has been drawn a ideal condition in compressive strength areas of concrete by an experiment. When applying 13mm of polyamide fiber, proper fiber mixing volume by compressive strength areas of concrete more than 2.5kg in 160MPa. These amount of a compound can control the explosion.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.571-572
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• 2009

Current design codes regarding compression lap splice dose not utilize merits of the improved strength of ultra-high strength concrete. Especially, a compression lap splice can be calculated longer than a tension lap splice according to the codes because they do not consider effects of strength of concrete and transverse reinforcement. Design equation is proposed for compression lap splice in 40 to 70 MPa of compressive strength of concrete. The proposed equation is based on 51 specimens. Through two-variable non-linear regression analysis of measured splice strengths, a splice strength equation is derived, which is converted into a splice length equation.

• Magazine of the Korea Concrete Institute
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• v.2 no.4
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• pp.8-21
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• 1990

• Journal of the Korea Institute of Building Construction
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• v.23 no.4
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• pp.381-392
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• 2023

This research scrutinizes the mechanical characteristics of ultra-high strength concrete using oxide graphene nanoplatelet(GO) and hollow glass powder(HGP). The investigation covered various mechanical attributes, including workability, compression strength, tensile strength, water resistance, and the internal microstructure of standard concrete. Our findings reveal that workability experiences a significant improvement with the incorporation of a minimal amount of HGP, and an increase was also observed in tensile strength and water resistance. It was confirmed that cGO(C company GO) and HGP demonstrated commendable dispersion and the pore volume exhibited a reduction of more than 20%. The potential of cGO and HGP to substitute silica fume(SF) was also explored. Consequently, it was found that both workability and mechanical properties were enhanced in the absence of SF when cGO and HGP were used. This finding implies that the utilization of these novel materials could potentially modify conventional methods of concrete manufacturing.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.677-680
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• 2008

The autogenous shrinkage of HPC is important in that it can lead the early cracks in concrete structures. The purpose of the present study is to explore the autogenous shrinkage of HPC with cellulose fiber and expansive additive and to derive a realistic equation to estimate the autogenous shrinkage model of that. For this purpose, comprehensive experimental program has been set up to observe the autogenous shrinkage for various test series. Major test variables were the quantity of expansive additive and cellulose fiber. Water-cement ratio is fixed with 13%. The autogenous shrinkage of HPC is found to decrease with increasing expansive additive and cellulose fiber. A prediction equation to estimate the autogenous shrinkage of HPC was derived and proposed in this study. The proposed equation shows reasonably good correlation with test data on autogenous shrinkage of HPC.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.202-213
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• 2003

Tower Palace III project is the highest residential and commercial high-rise complex building in Korea. In order to construct a high-rise building, advanced construction and engineering technology is required. Therefore, with more developed construction and engineering technology based upon accumulated knowledge, construction speed of 13.4 days per floor including finish work was achieved in this project. To achieve this project successfully, three main advanced construction technology were applied: 1) Construction methods for 3-day cycle of structural work and curtain wall, 2) Tact scheduling method for finish work, 3) Management system of material, labor, work, and information. Also, four main engineering technology were applied: 1) New material such as high -flowing concrete and high strength concrete of 800 kgf/cm2, 2) New method such as a pipe-cooling system of a cool water circulating type, 3) Mechanical system such as smart-fan controlling kitchen-ventilation system, 4) Electrical system such as false car system.

• 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.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.3
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• pp.149-160
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• 2015

This study reports the interfacial bond strength between Ultra High Performance Concrete (UHPC) and Normal Strength Concrete (NSC). While previous studies have focused on the interfacial strength between NSC substrate and UHPC overlay, this study use precast UHPC for enhanced constructability and replacement of formwork. The factors affecting the interface strength are comprehensively reviewed. It can be classified into: interface shape, degree of hardening and moisture condition of UHPC before combining with NSC, and curing condition of composite materials. Conducted experiments verify the effects of each factor on the interface strength and, accordingly show different failure modes. In particular, a new failure mode of the failure of a part of UHPC was firstly found in the case of sample with rough interface between UHPC and NSC. The other factors of the degree of hardening and the moisture and curing conditions of UHPC were discussed. This research will provide a valuable foundation to utilize the UHPC as a composite material.

• Cement Symposium
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• s.35
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• pp.236-241
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• 2008

• Cement
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• s.177
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• pp.40-51
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• 2008