• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.535-536
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• 2009

This study was carry out to evaluate the durability of Ductile Fiber Reinforced Cementitious Composites(DFRCC) according to W/B ratio(30, 40, 50%). The results is showing that DFRCC outstandingly improved to compare to plain concrete for the resistance of chloride ion penetration and rapid freezing and thawing

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.457-458
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• 2010

PHDC(Promoted High Durability Concrete) is developed for preventing the chlroide attack to concrete structure on the reclaimed ground. In this study, the basic characteristics and the field application of PHDC is examined through experiments, the durability standard of the company is suggested. the long-term monitoring experiment for measuring the chloride penetration is also performed.

• Cement Symposium
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• no.23
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• pp.245-249
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• 1995

• Cement
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• s.202
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• pp.48-52
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• 2014

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.2
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• pp.117-124
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• 2014

The interest in the use of shield TBM (Tunnel Boring Machine) on the tunnel excavation has been increased rapidly in Korea. The shield TBM tunnel is generally designed as non-drainage tunnel. Consequently, if water leakage through the segment joints happens, big problems on the usage and stability of tunnel can be occurred. In this study, the variation of waterproof capacity of hydrophilic waterstop by the construction error and excessive displacement of segment was studied firstly. Secondly, the decrease of durability of hydrophilic waterstop by the sulphate and chloride contained in the groundwater and seawater was investigated. The results showed that if the angle discordance at the segment joints is beyond the 2 degree, the proper waterproof capacity of hydrophilic waterstop can not be guaranteed. In addition, if the hydrophilic rubber waterstop is exposed to the sulphate for a while, the proper durability of hydrophilic waterstop can not be expected.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.277-280
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• 2008

Reinforced concrete structures have an excellent durability under a good construction and continuous maintenance. But reinforced concrete construction is influenced by atmospheric phenomena and it is creating a deterioration. One of the deterioration cause on concrete is a freezing and thawing action. Freezing and thawing leads to the reduction in concrete durability by the cracking or surface spalling. If we are carried out freezing and thawing, deterioration of reinforced concrete construction will be reduction. Therefore, this study was performed to investigate the flexural behavior of reinforced concrete beams exposed to freezing and thawing cycles. Thee presence of damage and cycles were considered as variablees in this study.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.2
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• pp.171-175
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• 2010

This paper presents the experimental results of frost durability characteristics including freezing-thawing and de-icing salt scaling of the concrete for gutter of the road and marine structure. Mixtures were proportioned with the three level of water-binder ratio(W/B) and three binder compositions corresponding to Type I cement with 0%, 30% and 50% GGBS(Ground granulated blast furnace slag) replacement. Also, two different solutions of calcium chloride were used to evaluate their effect on the frost durability resistance. Specially, in case of complex of freezing and thawing with salt and carbonation, the deterioration of concrete surface is evaluated. Test results showed that the BFS30 and BFS50 mixture exhibited higher durability and lower mass loss values than those made with OPC mix and the use of GGBS can be used effectively in terms of economy and frost durability of the concrete to be in complex deterioration. Therefore, the resistance to complex deterioration with freezing-thawing was strongly influenced by the strength and the type of cement.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.473-476
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• 2008

Due to the pursuit of high function and international price increase in the field of construction, the application of the secondary product using cement is on the increase gradually in the construction industry in the pursuit of economic cost reduction by the shortening of the construction time like Expediting and the dry construction method at the same time. However, it is in very urgent situation of measures to improve the structural performance or durable performance because it is limited for use in terms of panel in interior exterior building or functional repair reinforce as yet. Accordingly, this study is to investigate applicability of permanent Formwork like mould with the structural performance or excellent durable performance in the field of construction, and to derive optimum mixture in the performance and quality of manufacture. As a result of analysis comparison with the dynamic and durable properties of vacuum extrusion molding high toughness cement panel according to the mixture of four conditions, this study has found that the test body of mixing ECC-DP3 using small filler and large granulated blast furnace slag and powder flame retardant had excellent relative hardness and bending stress strain. The durable performance has shown excellent tendency by the decrease of porosity and enhancement of water-tightness.

• Journal of the KSME
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• v.33 no.11
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• pp.942-950
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• 1993

이 글에서는 자동차용 에어컨의 냉매 규제에 따른 대체냉매의 적용시 에어컨의 성능 변화를 이 론적으로 예측하여 보고, 냉매의 대체에 따른 응축기의 변경에 의한 성능 특성을 실험 결과로 설명하였다. 기존의 응축기(SPC)를 SCC로 교체함으로써 대체냉매를 사용하는 시스템에서 열전 달성능의 향상을 꾀할 수 있었다. 자동차용 에어컨에서 냉매의 교체에 따라 변경이 예상되는 부품으로는 응축기를 비롯하여 증발기, 팽창밸브, 수액기건조제, 압력스위치, 배관호스류, 압축기 압축기오일, 팬모터 등이 될 수 있다. 이러한 요소부품의 변경을 위해 연구개발되어야 할 기술 로는 먼저 운전 및 성능을 고려한 각 부품의 설계기술과 제작기술의 개발이 필요하다. 특히 자 동차의 내구연한의 확장에 따른 에어컨의 내구성 및 신뢰성의 문제는 지속적으로 연구되어야 할 것이다.

• 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.