• Proceedings of the Korea Concrete Institute Conference
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• 1998.10a
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• pp.313-318
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• 1998

Generally, the concrete constructed during cold weather has the frozen damage which cause the fatal damage so that heat curing and sheet curing was performed to prevent the early freezing of concrete. However, partial refrigeration caused by thermal gradient has many troubles so that the construction hasn`t been done as possible. This paper presents the development of strenth properties and optimal mix design against frozen damage under the cold weather, 1$0^{\circ}C$ below the zero.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.04a
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• pp.215-220
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• 1994

본 연구의 목적은 당사 콘크리트 배합설계 프로그램인 쌍용배합설계시스템(Ssangyong Mix Proportioning Design System ; 이하 SMPD라 칭한다)을 기본으로해서 슬래그시멘트에 대한 콘크리트 배합설계(안)을 제안함으로써 콘크리트 현장에서 합리적으로 콘크리트를 제조할 수 있도록 하는데 있다. 연구 내용은 슬래그시멘트와 보통시멘트간의 콘크리트 물성차이를 실험실적으로 규명하기 위해서 슬래그 함유량 및 양생 온도별로 슬래그시멘트의 콘크리트 강도발현특성, 물시멘트비, 단위수량변화 및 응결특성 등을 검토하였으며 그 결과를 이용하여 슬래그시멘트의 콘크리트 배합설계를 시행, 표준배합과 현장배합표를 제시하였다.

• Journal of Industrial Technology
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• v.16
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• pp.25-30
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• 1996

The waste foundry sand might be recycled in concrete, resulting in energy saving and environmental protection. An half Factorial Experiments were performed with the variables of W/C ratio, S/A, Sand/Waste foundry sand ratio and Slump as a preliminary study for optimum mix design of concrete. The results show that then W/C ratio is the most important factor to the concrete strength. The substitute of waste foundry sand up to 30% has little influence, saying that it can substitute the fine aggregate without damaging the concrete properties.

• Journal of Industrial Technology
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• v.16
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• pp.39-44
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• 1996

The waste basalt might be recycled in concrete, resulting in energy saving and environmental protection. An half Factorial Experiments were performed with the variables of W/C ratio, S/A, Crushed stone/Basalt ratio and Slump as a preliminary study for optimum mix design of concrete. The results show that the W/C ratio is the most important factor to the concrete strength. The substitute of waste basalt up to 100% has little influence, saying that it can substitute the coarse aggregate without damaging the concrete properties.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.85-86
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• 2016

Recently damages caused by the additional costs and degradation in durability combined deterioration due to plain concrete deterioration has occurred. In particular, in the case of the finish that is not exposed to the outside air in the concrete to respond to the harsh environment (freeze-thawing, calcium laying, etc.), to establish a quality control way for the process and the concrete mix design for it.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.58-63
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• 1996

The waste foundry sand might be recycled in concrete, resulting in energy saving and environmental protection. An half Factorial Exprements were performed with the variables of W/C ratio, S/A, Sand/Waste foundry sand ratio and Slump as a preliminary study for optimum mix design of concrete. The results show that the W/C ratio is the most important factor to the concrete strength. The substitute of waste foundry sand up to 30% has little influence, saying that it can substitute the fine aggregate without damaging the concrete properties.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.94-95
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• 2020

This paper introduces the mix design and performance evaluation of Ultra-High Performance Concrete (UHPC). The concrete mixture is designed to achieve a densely compacted cementitious matrix via the modified Andreasen & Andersen particle packing model. The compressive strengths of UHPC designed by this method reached 154MPa. The relationship between packing theory and compressive strength of UHPC is discussed in this paper.

• International Journal of Highway Engineering
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• v.11 no.2
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• pp.1-15
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• 2009

Surface of exposed aggregate concrete pavements is consists of exposed coarse aggregate by removing upper 2$\sim$3mm mortar of concrete slab. Exposed aggregate concrete pavements have advantages of maintaining low-noise and adequate skid-resistance level during the performance period. In order to provide the successful exposed concrete aggregate pavement, uniform distribution of the coarse aggregate on pavement surface through adequate the mix design and exposing method. The mix design in concrete pavement is generally designed on the basis of strength, but mix design of exposed aggregate pavement employed in this study includes the consideration of noise and skid resistance, as well as strength. Smaller of maximum coarse aggregate is known to be effective for reduce noise level. Optimum mix design and exposing method of fine-size exposed aggregate portland cement concrete pavement that can reducing the noise and maintain the adequate level of skid resistance are proposed in this study. To consider the variation of optimum exposing time due to the hardening speed of mortar by climatic condition, quantitative is also suggested measurement of hardening state.

• Journal of the Korean housing association
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• v.23 no.2
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• pp.1-14
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• 2012

In Korea, apartment complexes are built according to the social strata for which they are intended to house, thus the buildings tend to separate society both physically and even visually. Because of the sense of social exclusion this has caused the government has conceived a plan to develop a "social-mix" apartment complex master plan. Perhaps the foremost example of this type of plan is the Seoul Eunpyeong New Town. This study examines how resident's perception of the social mix plan has evolved, and also attempts to better understand the effectiveness of the government's attempt at social integration. The result shows that the perception of social-mix housing has improved after residents moved into the Eunpyeong New Town and that people responded positively to the concept of actually mixing residents socially. From the result, we can see that the visually unexposed environmental elements of rental housing and socials exclusion which was felt in the past has been reduced to a certain extent. However, residents living in solid-lot apartments have a negative reaction to social mixing especially when they are in the same building. Therefore, to achieve better social integration in a socially-mixed apartment complex, we need now to change the perception toward socially mixed housing among the residents living in solid-lot apartment buildings.

• Journal of Information Processing Systems
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• v.8 no.1
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• pp.175-190
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• 2012

Shuffling is an effective method to build a publicly verifiable mix network to implement verifiable anonymous channels that can be used for important cryptographic applications like electronic voting and electronic cash. One shuffling scheme by Groth is claimed to be secure and efficient. However, its soundness has not been formally proven. An attack against the soundness of this shuffling scheme is presented in this paper. Such an attack compromises the soundness of the mix network based on it. Two new shuffling protocols are designed on the basis of Groth's shuffling and batch verification techniques. The first new protocol is not completely sound, but is formally analyzed in regards to soundness, so it can be applied to build a mix network with formally proven soundness. The second new protocol is completely sound, so is more convenient to apply. Formal analysis in this paper guarantees that both new shuffling protocols can be employed to build mix networks with formally provable soundness. Both protocols prevent the attack against soundness in Groth's scheme. Both new shuffling protocols are very efficient as batch-verification-based efficiency-improving mechanisms have been adopted. The second protocol is even simpler and more elegant than the first one as it is based on a novel batch cryptographic technique.