• Journal of the Society of Disaster Information
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• v.20 no.1
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• pp.20-31
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• 2024

Purpose: Research and development of high-strength concrete enables high-rise buildings and reduces the self-weight of the structure by reducing the cross-section, thereby reducing the thickness of beams and slabs to build more floors. A large effective space can be secured and the amount of reinforcement and concrete used to designate the base surface can be reduced. Method: In terms of field construction and quality, the effect of reducing the occurrence of drying shrinkage can be confirmed by studying the combination of low water bonding ratio and minimizing bleeding on the concrete surface. Result: The ease of site construction was confirmed due to the high self-charging property due to the increased fluidity by using high-performance water reducing agents, and the advantage of shortening the time to remove the formwork by expressing the early strength of concrete was confirmed. These experimental results show that the field application of ultra-high-strength concrete with a design standard strength of 100 MPa or higher can be expanded in high-rise buildings. Through this study, we experimented and evaluated whether ultra-high-strength concrete with a strength of 130 MPa or higher, considering the applicability of high-rise buildings with more than 120 floors in Korea, could be applied in the field. Conclusion: This study found the optimal mixing ratio studied by various methods of indoor basic experiments to confirm the applicability of ultra-high strength, produced 130MPa ultra-high strength concrete at a ready-mixed concrete factory similar to the real size, and tested the applicability of concrete to the fluidity and strength expression and hydration heat.

• Korean Journal of Heritage: History & Science
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• v.46 no.4
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• pp.108-125
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• 2013

This study examined the actual reconstruction drawing, composite mineral, particle size and property test, fine organic matters, color differences and main ingredients of the earthen mold excavated in Dongcheon-dong, Gyungju. The cross-section of the inner mold and outer mold divides into inside (1st layer) and outside (2nd layer), with organic matters mixed outside. The cross-section has been altered due to heat and form removal agent. X-ray analysis revealed that the layer was made of minerals with high transmissivity and only quartz particles were observed through a polarizing microscope. The inside of cross-section in SEM observation identified enlarged air gap, with crack developed in the center, but no changes observed on the outside. The particle size of the composites is almost the same for the inner mold and outer mold and is silt clay loam. The ratio between silt clay and silt clay loam was about 2.7:1 and 2.9:1 respectively. In the property test, the density and absorption rate of inner mold and outer mold were similar, but porosity was different, with inner mold of 27.36% and outer mold of 31.09%. The color difference of cross-section seems to have been caused by the spread of soot on the 1st layer surface for removal of form or by the covering of ink to protect the 1st layer. Composite mineral analysis revealed the same composition for the inner mold and outer mold, except for the magnetite that was detected in the inner mold alone. As for the main ingredient analysis, the average content of $SiO_2$ was 71.64% and that of $Al_2O_3$ was 14.59%. As for the sub-ingredients, $Fe_2O_3$ was 4.51%, $K_2O$ 3.06%, $Na_2O$, MgO, CaO, $TiO_2$, $P_2O_5$ and MnO was less than 2%.

• Journal of the Korean Society of Floral Art and Design
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• no.45
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• pp.77-95
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• 2021

This study considers the problem of reality that our floral art has to overcome as a loss of the floral art spirit caused by the expansion of Western-centered formalism flower culture, and considers the discussion on the deformality of distancing and the free spirit of nomadism. The floral art, which works on the creator's aesthetic mental world through flowers, is an art of mental image that values the free mental world of the creator. It also refers to the importance of artist consciousness as an art of self-imago that makes the target world beyond the "expression of similarity" that reproduces the target world. In this context, the lack of concern about the identity of Korean floral art appears to be the creative training and work of Korean floral artists who are biased toward Western expression techniques and creative methods. It also expresses a problem with our cultural consciousness, which is dominated by the Western flower culture of flower design. Here, we are obliged to understand the reality of Korean floral art biased by Western flower design and to organize discussions to solve the problem. Therefore, this study examines the problems that our floral art has to overcome as part of seeking the identity of Korean floral art and enhancing the cultural value of Korean floral art through criticism of Western cultural acceptance. This is a historical consideration of the nature of Korean floral art to recover, while also a process of identifying the meaning of the free creative spirit that the artist should maintain as an aesthetic art. Furthermore, such criticism of the Korean floral art culture and discussion of introspection are expected to serve as an opportunity to further expand the academic discourse system for the floral art while embodying the "identity" of Korean floral art.