• 콘크리트학회논문집
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• 제18권2호
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• pp.205-211
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• 2006

본 연구는 팽창재와 수축저감제를 조합 사용하여 수축변형률이 저감된 저수축 고성능 콘크리트에 대하여 내구성을 평가하였다. 그리고 저수축 고성능 콘크리트와 비교를 위해 동일한 물-결합재비에서 팽창재와 수축저감제를 사용하지 않은 고성능 콘크리트와 일반 콘크리트에 대해서도 시험을 실시하였다. 그 결과, 저수축 고성능 콘크리트는 동일한 물-결합재비를 가진 고성능 콘크리트에 비해 압축강도와 인장강도가 다소 크게 나타났다. 염소이온 침투 저항성과 탄산화에 대한 저항성은 고성능 콘크리트와 일반 콘크리트에 비해 우수하며, 동결융해 저항성은 동결융해시험 600사이클에서도 내구성 지수가 거의 100으로 나타났다. 또한 수밀성과 공극분포를 검토한 결과, 저수축 고성능 콘크리트는 고성능 콘크리트 또는 일반 콘크리트에 비해 시멘트 경화체 조직이 치밀해져 내구성이 향상되는 것으로 분석되었다. 따라서 팽창재와 수축저감제를 조합사용한 저수축 고성능 콘크리트를 구조물에 적용한 경우, 콘크리트의 수축과 균열을 저감시킬 수 있을 뿐만 아니라 내구성능이 향상되는 결과를 얻을 수 있을 것으로 분석되었다.

• 자동차안전학회지
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• 제8권1호
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• pp.26-30
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• 2016

The steel road wheel on ventilation holes was cracked in the vehicle durability test. But the component durability test by uni-axial, CFT(Cornering Fatigue Test) and RFT(Radial Fatigue Test) had been satisfied. That is, the uni-axial component test could not forecast the crack of vehicle. Therefore this study developed the bi-axial test mode to reflect a vehicle condition(to reflect both vertical and lateral force simultaneously) based on real load data which was measured in Europe and China and developed CAE simulation too. It reproduced the cracks same as vehicle's and verified by bi-axial test machine in the LBF(Fraunhofer Institute for Structural Durability and System Reliability) durability research center in Germany. Finally this the durability CAE simulation by using HMC(Hyundai Motor Company)'s the bi-axial test mode predicts feasibly the steel wheel's durability performance before vehicle durability test.

• Tribology and Lubricants
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• 제25권5호
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• pp.285-291
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• 2009

In this work, durability characteristics of electrorheological (ER) fluid for damper application are experimentally investigated. ER fluid is prepared by using phosphorated starch particles and silicone oil. The field-dependent Bingham characteristics and response time for the proposed ER fluids are experimentally obtained. Experimental apparatus of durability test for ER fluid is established with cylindrical ER cylinder for mid-sized passenger vehicle. In order to evaluate the durability characteristics of ER fluid as a function of time, damping force and temperature variations are measured until one million cycles. After durability test, Bingham characteristics and response time of ER fluid are measured and compared to the initial properties. Microscopic pictures of ER fluid are taken to validate the changes of properties. The results indicate that the ER fluid can be commercially utilized in vehicle damper system with its durability performance. Moreover, the understanding of durability characteristics is essential to predict the service life of ER fluid as well as to design its applications.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1431-1438
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• 2007

This paper presents a refined design model for current railroad design code on concrete structures exposed to marine environment. A time-varying diffusion coefficient(D) as well as surface chloride$(C_S)$ and chloride threshold level$(C_{lim})$ are studied. Averaging value of the D with time over exposed duration were used to refined durability design model to consider time dependent characteristic of D. The values for $C_S$ and $C_{lim}$ for the seashore in Korea revised for realistic durability design. The proposed model was verified by the so-called performance-based durability design, which is widely used in recent durability design code. Results show that the current standard specification underestimates durability performances of concrete structures exposed to marine environment, so that the cover depth design using current durability evaluation in the standard specifications is very much conservative. Thus, it is found that proposed durability design models for the railroad design code for railway concrete structures can be used effectively for service life design of concrete structures in marine environment.

• 한국구조물진단유지관리공학회 논문집
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• 제7권1호
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• pp.139-145
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• 2003

Ternary blended concrete, which contains both fly ash and granulated blast furnace slag, has an initial cost effective and is environment friendly. Furthermore, it has a lot of technical advantages such as the improvement of long term compressive strength, high workability, and the reduction of hydration heat. However, as the use and study on the performance of ternary blended concrete is limited, it is worthwhile studying the actual performance of this technology. This study examined the durability performance of ternary blended concrete, compared to binary blended concrete and ordinary portland concrete. It led to the conclusion that ternary blended concrete is very suitable for submerged members under marine environment. However, it should be noticed that ternary blended concrete becomes weak on carbonation, when it is situated on combined deterioration environment of carbonation and chloride. Therefore, the curing duration of ternary blended concrete should be prolonged in order to enhance the resistance of carbonation.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.491-494
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• 2005

The present report addresses the durability related design issues for the structural reinforced concrete of the Busan-Geoje Fixed Link - Bridges and Immersed Tunnel. The overall aim of the durability related issues is to establish the requirements to the design and the construction that will secure the stated and achieve that objective with cost effective construction. To prove that the stated design life of 100 years is valid, a performance and reliability based verification, according on the DuraCrete approach have been performed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 가을 학술발표회 논문집
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• pp.80-83
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• 1995

In order to develope and apply high-performance steel fiber reinforced concrete (SFRC), the effects of steel fibers on durability and long-term deformation of SFRC due to various mixing conditions have been studied. As the test result show, the manufacturing process technology of industrial SFRC is developed And the durability of SFRC such as freeze-thaw, resisteance abrasion resistance are significantly improved, the drying shrinkage of SFRC, is remarkably decreased by increasing the steel fiber contents than plain concrete

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.676-681
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• 2000

This paper covers durability and field application of marine concrete which have been enhanced the resistance against deterioration in seawater. Fly ash concrete is applied to make the concrete with good durability. It is well known fly ash in concrete has a good performance preventing fro a sulphate attack and a steel corrosion. Several durability tests were performed to find characteristics of marine concrete which is proposed in this paper comparing with normal concrete. Field application was executed to compare results with laboratory test and to give a reliability to engineers. The project was supported by Ministry of Marine Affairs and Fisheries for two years.

• 한국정밀공학회지
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• 제14권12호
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• pp.135-142
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• 1997

New approach to determine thd design of automotive tire profile was introduced. In this study, design technology for tire profile was combined with a finite element method to improve high speed durability. Static and dynamic behavior analysis of new concept tire was compared with conventional tire profile. To obtain the improved tire performance, appropriate design values, ie. design methodology, section profile selection, material properties, are needed.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.101-102
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• 2023

This study aims to mix the base concrete by mixing latex to improve the durability performance to reduce the composite deterioration of the base concrete. Latex fiber has high resistance to freezing and thawing, adhesion, and deicing agent (calcium chloride), and it is used to secure long-term durability to reduce cracking and compound deterioration of concrete. In addition, through experiments, we are trying to find ways to improve the strength of concrete by studying the mixing of the appropriate mixing ratio of latex.