• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.3
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• pp.269-275
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• 2020

In this study, flexural tests of precast concrete panels according to the thickness of cross-sectional and the with or not of reinforcement were carried out in order to develop and assess of a lightweight precast concrete panel using ultra high performance concrete. For the test, four panels were fabricated, and consisted of one normal concrete panel and three ultra high performance concrete panels. As a test result, it was found that the plain precast panel using ultra high performance concrete had a lower flexural performance than the reinforced normal concrete panel, regardless of the cross-sectional size. The flexural performance of the hollow-sectional precast panel applying ultra high performance concrete, is improved by 150% compared to that of the reinforced normal concrete panel. That is, through additional performance verification and optimization of the cross-sectional design of the panel, the ultra high performance concrete precast panel can be made lighter. Also, the practical use of lightweight precast panels with ultra high performance concrete can be available through evaluation on shear, joint connection and anchoring, etc.

• Journal of the Korea Institute of Building Construction
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• v.22 no.3
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• pp.229-237
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• 2022

Ultra High Performance Concrete(UHPC) is a construction material that has a low water-binder ratio (W/B), a high-performance chemical admixture(SP), mixing material and steel fiber, and performance superior to that of regular concrete in terms of liquidity and strength. In the study, UHPC was used to prepare construction external panels that can replace existing stone panels. In addition, experiments were conducted to access the effects of differences in chemical admixture input amount, the number of fillers, antifoaming agent and steel fiber. An evaluation, was conducted, such of concrete compressive strength, flexural strength, impact strength, absorption rate, and frost resistance. The results showed compressive strength up to 115.5MPa, flexural strength of 20.3MPa, and an absorption rate of 1%. In this case, impact strength and frost resistance evaluation were satisfied with outward observed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.219-220
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• 2023

We attempted to examine field applicability by manufacturing panels using UHPC and conducting mock-up tests. Mock-up testing was conducted at the Busan location. To observe field applicability over a long period of time, it was produced and installed identically to actual panels.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2009.04a
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• pp.61-66
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• 2009

최근 초고층 건축물 등에 적용되는 고강도콘크리트의 내화성능에 대한 문제점이 제기됨에 따라 국토해양부에서는 고강도콘크리트 내화성능 관리 기준을 고시한 바 있으며, 건설업계에서도 이에 대응하기 위해 다양한 기술 검토가 이루어지고 있다. 본 연구에서는 고강도콘크리트의 취약점으로 제기되고 있는 화재시의 폭렬문제에 대한 대응방안으로서 기존 연구를 통해 내화성능이 우수한 것으로 보고되고 있는 ECC 를 영구거푸집으로 활용한 고강도콘크리트의 내화성능을 검토하였다. ECC 영구거푸집을 활용한 고강도콘크리트 기둥부재의 내화성능 검토 결과, 영구거푸집과 고강도콘크리트 계면으로의 열 침투를 제어할 수 있도록 부재 생산 및 구축 방안을 검토하고, ECC의 적정 배합 및 두께를 확보한다면 고강도콘크리트의 내화성능 확보기술로서의 활용이 가능할 것으로 판단된다. 또한, 내화성 영구거푸집으로서의 단순 활용 방안 이외에 ECC의 우수한 물리적 성능을 활용하여 구조성능을 분담할 수 있는 방안으로의 지속적 검토가 필요할 것으로 판단된다.

• Journal of the Korea Institute of Building Construction
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• v.10 no.2
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• pp.89-96
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• 2010

This study was based on an experiment that examines the manufacture and performance of fiber-reinforced cement composite panels. The conclusions were drawn after testing the mechanical properties and durability characteristics of fiber-reinforced mortar, and the mechanical properties and fire resistance of ECC fire resistant column panels. It was found that the fluidity of CEL fiber was lower than that of PVA and NY fiber. The amount of air increased slightly as the combination of fibers caused the number of fine pores to increase. It was found that the mechanical performance and deformability of high strength concrete could be improved through the confinement effect of ECC fire resistant column panels. Through continuous studies on the manufacturing and field construction methods of fire resistant column panels, a new PC method that eliminates weakness in the existing processes may be developed for skyscrapers.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.3
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• pp.210-217
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• 2023

Various performances of ultra-high performance concrete (UHPC) applied with microplastics and expanded polystyrene (EPS) beads were evaluated. CompressIve and flexural strength, performance after ignition, flow-down in fresh state, and effective bond strength were evaluated. Designed weight of the cement panel with these mixtures was calculated based on the flexural strength. As a result of the experiments, it was confirmed that the EPS could reduce the density of UHPC with largest range. By maximum addition of EPS beeds, the density of UHPC decreased to 1300 kg/m³, and the compressive and flexural strengths for this mixtures were in ranges of 20-30 MPa and 15-20 MPa, respectively. On the other hand, lightest cement panel could be designed with UHPC having a density ranges about 2.0 g/cm³.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.176-177
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• 2022

In this study, surface performance evaluation was conducted according to the fiber and surface finishing technique of the exterior material using Ultra High Performance Concrete(UHPC), whitch is spotlighted as a highly durable exterior material. As a result of outdoor exposure, the initial performance of the UHPC Panel using organic fibers was maintained without being affected by the surface finishing technique. In the specimen using steel fiber, the surface performance was maintained when the water repellent treatment was performed in the plain specimen, but fiber corrosion occurred in the specimen to which the surface finishing technique was applied.

• Journal of the Korea Institute of Building Construction
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• v.23 no.3
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• pp.251-260
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• 2023

The construction of free-form structures with intricate curved exteriors necessitates the use of bespoke molds. To fulfill this requirement, a blend of Phase Change Material(PCM) and Ultra-High Performance Concrete(UHPC) is utilized. PCM endows the solution with recyclability, while UHPC facilitates the effortless execution of curvature in the mold fabrication process. However, it's worth mentioning that the melting point of PCM hovers around 58-64℃, and the heat emanating from UHPC's hydration process can potentially jeopardize the integrity of the PCM mold. Hence, experimental validation of the mold shape is a prerequisite. In the conducted experiment, UHPC was poured into two distinct mold types: one that incorporated a 3mm silicone sheet mounted on the fabricated PCM mold(Panel A), and the other devoid of the silicone sheet(Panel B). The experimental outcomes revealed that Panel A possessed a thickness of 3.793mm, while Panel B exhibited a thickness of 5.72mm. This suggests that the mold lacking the silicone sheet(Panel B) was more susceptible to the thermal effects of hydration. These investigations furnish invaluable fundamental data for the manufacturing of ultra-high strength irregular panels and PCM molds. They contribute substantially to the enrichment of comprehension and application of these materials within the realm of construction.