• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1999.06a
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• pp.265-268
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• 1999

경량 건축소재는 협소공간의 고도 이용과 건설 분야의 양적, 질적인 측면에서 급속한 성장으로 건축자재의 경량화, 고급화 및 다양화를 요구하고 있으며 이에 PE, PP, PS, PVC 등의 플리스틱 foam 및 저밀도 콘크리트 등의 경량 건축 소재에 대한 연구가 지속되고 있다. 경량 건축소재로 사용되는 플라스틱류는 대부분 난연화 및 강도유지를 위해 난연제, 섬유 및 무기충진제 등를 첨가하거나 고밀도화하여 사용하며 경량화를 위해 foaming agent를 사용하여 기포를 발생시켜 경량화하여 성형된다. (중략)

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.5
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• pp.333-340
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• 2019

Tests using a middle velocity propulsion impact machine (MVPIM) were performed to verify the impact resistance capability of sandwich concrete panels (SCP) in a modular liquefied natural gas (LNG) outer tank, and numerical models were constructed and analyzed. $2{\times}2m$ specimens with plain sectional characteristics and specimens including a joint section were used. A 51 kg missile was accelerated above 45 m/s and impacted to have the design code kinetic energy. Impact tests were performed twice according to the design code and once for the doubled impact speed. The numerical models for simulating impact behaviors were created by LS-DYNA. The external steel plate and filled concrete of the panel were modeled as solid elements, the studs as beam elements, and the steel plates as elasto-plastic material with fractures; the CSCM material model was used for concrete. The front plate deformations demonstrated good agreement with those of other tests. However the rear plate deformations were less. In the doubled speed test for the plain section specimen, the missile punctured both plates; however, the front plate was only fractured in the numerical analysis. The impact energy of the missile was transferred to the filled concrete in the numerical analysis.

• Journal of the Korea Concrete Institute
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• v.19 no.4
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• pp.475-482
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• 2007

The property and applicability of the organic-inorganic synthesized penetrating and reinforcing agent, which is developed in order to improve durability of concrete structures and prevent deterioration that may occur as service years increased, are researched with experimental works. TEOS (tetra-ethoxyorthosilicate) and acrylate monomer are synthesized by the solution polycondensation method in order to formulate silicate with sol-gel process and improve durability of concrete. Additional substances such as isobutyl-orthosilicate is supplemented in order to improve the performance of the agent. After the developed organic-inorganic penetrating reinforcing agent penetrates, a flexible impact alleviating layer is formed with organic monomers as well as the agent strengthens concrete by filling up the internal pore of concrete with stable compounds after penetration. Penetrating and reinforcing agent can be applied as an effective life management method because it makes concrete more durable against the aging factors, such as chloride ion, carbonation, freezing-thawing, and compound aging.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.6
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• pp.727-733
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• 2009

This study was performed to investigate the physical characteristics like compressive strength, permeability, porosity and the water quality removal characteristics of permeable concrete pavement filled with microbial-soil sheet to remove SS, organic matter and nutrients in artificial rainfall. As a result, it can show the removal efficiency is SS 90~95%, COD 85~93%, BOD 80~83%, T-N 61~75%, T-P 71~78% on WAPS I(W1) and WAPS II(W2). Therefore, permeable concrete pavement filled with microbial-soil sheet shows higher removal efficiency(SS 10%, organic matter and nutrients 30%) than a conventional porous concrete(W3). By filling microbial-soil sheet to permeable concrete pavement, we confirm that the function and efficiency are improved significantly and that a naturally-friendly facility can be developed and applied to treat non-point sources.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.823-828
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• 2002

Concrete used up to date semipermanent architecture material but now day concrete early deterioration emboss social issue because of construction structure and environmental factor. so, many study of deterioration concrete construction improve durability used impregnation alkalization agent. Impregnation alkalization agent deterioration concrete construction spray infiltration or diffusion improve alkali and filler inter minuteness void elaborateness constitution concrete. but many study of harding concrete change inter minuteness void that Is insufficiency also, To study of method recover shape impregnation alkalization agent apply deterioration concrete construction. impregnation alkalization agent infiltration according to test of porosity, premeameter, absorption.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.775-780
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• 2002

Sandwich panel made by foamed styrene and ployuretane has been used generally in the construction area because of the high thermal conductivity and light weight but they occur harmful gases to both bodies and environments in the high temperature over $50^{\circ}C$. So, the purpose of this study is to investigate the physical properties of light-weight panel using the non-structural lightweight aggregate as a part of the substitution of foamed styrene and ployuretane. This paper dealt with the effect of the addition of polymer dispersion such as SBR, St/BA-1 and St/BA-2 having polymer-cement ratio as 5, 10, 15% and the filling ratio of continuous void as 50, 60% on the strength of polymer-modified sandwich panel core. From the results, we could know that the compressive and flexural strength of the sandwich panel core using non-structural lightweight aggregate and polymer dispersion such as SBR, St/BA-1 and St/BA-2 tended to be increased with an increase in the polymer-cement ratio and the filling ratio of continuous void.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.626-629
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• 2006

Suk-San highway bridge, located on a soft ground environment, had been examined the current condition of settlement estimation throughout G.P.R(Ground Penetrating Radar), general observation and visual observation(video camera & scope). According to the above observations, the ground of this area has sunk about thirty centimeters since 1996. Also, currently, Suk-San highway bridge has been disjoining the gap between the structure and ground. Therefore, it is necessary to fill it up the gap. The purpose of this paper is to report the effects of Sunk-San highway bridge was observed by G.P.R. & general observation etc. and to present the results of repair of Suk-San highway bridge filling the gap up.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.483-486
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• 2003

본 연구는 운동장, 주차장, 도로측면, 보도, 기타 주거시설 등의 우수 찻집시설에 사용되는 콘크리트 구조물의 침투능 확보를 위한 투수성 찻집 구조물 개발에 관한 것이다. 투수성을 확보하기 위하여 일반 차집시설의 콘크리트 구조체 벽면에 천공을 하고 천공된 측구 내에 쇄석을 충진시켜 침투되는 우수의 수질도 개선할 수 있다. 본 제작방법은 별도의 침투소재를 사용하는 경우와 비교해 볼 때 경제성이 우수하며 동일시공방법과 규격으로 대체재로서 활용성이 높을 것으로 전망된다, 본 연구에서 개발하고 있는 여재를 이용한 침투시설은 침투능을 충분히 확보할 수 있음을 확인하였고 SS기준으로 27％∼86％의 제거율을 보였으며, COD기준 20％∼68％의 제거율을 나타냈으며, 탁도기준 29％∼88％의 제거율을 볼 수 이었다.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.464-469
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• 2000

Since the occurrence of 1995 Kobe earthquake, there have been much concern about seismic design for various infrastructures, inclusive of bridge structures. This research aims at evaluating the seismic performance of the existing R/C bridge piers, which were nonseismically or seismically designed in accordance with the provision of Korea Highway Design Specification. Further experimental investigations have been doing to figure out the retrofitting effects of nonseismic R/C bridge piers confined with glass fiber at the plastic hinge zone. Pseudo-dynamic tests have been carried out in nine scaled R/C column specimens to investigate their hysteretic behavior under earthquake loading. Test parameters are axial load, input ground motion confinement steel ratio, glass fiber and etc.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.2
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• pp.172-179
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• 2005

A high-precision centerless grinding machine has been recognized as a core equipment performing the finish outer-diameter grinding process of ferrules which are widely used as fiber optic connectors. In this study, in order to realize the high-precision centerless grinding machine, the structural characteristic analysis and evaluation are carried out on the virtual prototype consisted of the steel bed, hydrostatic GW and RW spindle systems, hydrostatic RW feed mechanism, RW swivel mechanism, and on-machine GW and RW dressers. The loop stiffnesses of centerless grinding machine are estimated based on the relative deformations between GW and RW caused by the grinding forces. And the simulated results illustrate that the concrete-filled bed has the considerable effect on the improvement of the structural stiffness of centerless grinding machine.