• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.45-50
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• 1997

Recycling of waste concrete will contribute not only to the solution of a growing waste disposal problem, also help to conserve natural resources of aggregate and to secure future supply of reasonably recycled aggregates for building construction purpose within large urban areas. Therefore, the purpose of this study is to analyze the applicability of recycled concrete in the influence of a substitute rate of recycled aggregate. As the result of this study, it is possible to conform that the recycled aggregate concrete substituted by 30~50% of the crushed aggregate can be applicated in site.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.4 no.4
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• pp.215-220
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• 2000

This study on the incineration ash and sintering pellet from sewage sludge was carried out to evaluate the possibility of recycling in sewage sludge disposal. The samples used in this experiment were raw sewage sludge, its incineration ash, and sintering pellet. The characteristics of the three sample types were identified using X-ray diffraction(XRD), X-ray fluorescence(XRF), atomic absorption spectroscopy(AAS), and inductively coupled plasma spectroscopy(ICP). The chemical compositions of all three sample types were similar in their clay component, however, the sewage sludge had a high content of organic materials. From an analysis of the mineral content of the three sample types, the conversion of their compositions was found to be relative to temperature. Accordingly, incineration ash and sintering pellet both have potential for use as a functional construction material.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.643-652
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• 2009

This paper presents brief history and a state-of-the-art survey of Life Cycle Cost (LCC) analysis, in particular LCC analysis in the Urban Transit Vehicle, based on a internationl codes and standards related to LCC analysis. A main objective of the LCC analysis is to quantify the total cost of ownership of a product throughout its full life cycle, which includes research and development, construction, operation and maintenance, and disposal. The predicted LCC is useful information for decision making in purchasing a product, in optimizing design, in scheduling maintenance, or in planning overhaul. This paper presents a LCC procedure consisting of seven steps, which are "Problems definition", "Cost elements definition", "System modeling", "Data collection", "Cost profile development", "Evaluation", and "Verification". Sub-activities to be encompassed in the seven steps procedure are described.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09c
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• pp.140-145
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• 2010

Consolidation in cohesive soils mainly focuses on compressibility of soils, but it affects solute transport in some cases. The consolidation process takes on particular significance for fine grained soils at high water content, such as dredged sediments, but has also been shown to be important for compacted clay liners during waste filling operation. Numerical investigation using CST1 and CST2 was reviewed on consolidation-induced solute transport in this paper, especially with the development of CST2 model, verification by comparing experimental results with numerical simulations, and cases studies regarding transport in a confined disposal facility (CDF) and during in-situ capping. The importance of the consolidation process on solute transport is accessed based on simulated concentration or mass breakthrough curves. Results indicate that neglecting transient consolidation effects may lead to significant errors in transport analyses, especially with soft contaminated cohesive soils undergoing large volume change.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.381-384
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• 2004

Delaying and objection for the construction of storage spent-fuel disposal has prompted to consider expanding on-site storage of spent reactor fuel since it can eliminate the need for costly and difficult shipping and control of the spent fuel completely under the direction of the owner-utility. The dry storage unit developed in Canada can accommodate Korea heavy water reactor fuel elements and become a candidate for the Korean market. In this paper, finite element analyses were carried out in order to investigate the structural behavior of the nuclear spent fuel dry storage system, which is subjected to impact loads such as collision of a truck load and dropping of flask under the irregular operation.

• Advances in concrete construction
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• v.4 no.4
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• pp.283-303
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• 2016

Several types of industrial byproducts are generated. With increased environmental awareness and its potential hazardous effects, the utilization of industrial byproducts in concrete has become an attractive alternative to their disposal. One such by-product is ground granulated blast furnace slag (GGBS), which is a byproduct of the smelting process carried out in the iron and steel industry. The GGBS is very effective in the design and development of high-strength and high-performance concrete. This paper reviews the effect of GGBS on the workability, porosity, compressive strength, splitting tensile strength, and flexural strength of concrete.

• Journal of the Korean institute of surface engineering
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• v.14 no.4
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• pp.221-233
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• 1981

Section 102(2) (c) of the National Environmental Policy Act of 1969 of the United States requires an environmental assessment of the major federal actions that could significantly a-ffect environmental quality. The review is known as the NEPA assessment process, and the resulting document is called an Environmental Impact Assessment (EIS). Article 5 of the En-vironmental Preservation Law of ROK also introduced this system to a cereain extent. The purpose of this paper is, therefore, to review the general impacts of environmental pollution caused by newly proposed actions on air quality, water resources, and land use as well as specific impacts from the disposal of radiation wastes, operation of petroleum and ru-bber industries, construction of highways and dams, location of power plants and industrial co-mplexes, etc., in order to fully understand the importance of this system. Differences between American and Korean system are also briefly studied and reached to a conclusion that this important system should be understood in such a way as to link and uti-lize all conceivable disciplines and human knowledge in order to protect our environment by all means for ourselves and our coming generations as well.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.59-62
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• 2019

인천신항 내 기존 준설토 투기장은 2018년에 수토가 완료 될 예정이므로 향후 항만개발과 운영시 발생되는 준설토의 원활한 처리를 위해서는 신규 준설토 투기장 조성이 필요하다. 투기장 조성을 위해서는 중 장기적인 준설토 처리방안 등을 고려한 항만기능 향상과 경쟁력 강화를 위한 준설토 투기장 호안 축조가 선행되어야 하기 때문에 극동건설 컨소시움에서는 퍼펙트델타라는 설계컨셉을 수립하고 내구성과 안전성을 강화한 설계, 조기수토 공간확보 및 수토용량 증대, 자연과 인간 도시가 함께하는 환경 친화적인 설계, 현장여건에 가장 적합한 설계를 구현하였다.

• Journal of Drive and Control
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• v.18 no.4
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• pp.43-51
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• 2021

In this study, we designed a hydraulic propulsion propeller system that allows dredged materials to be carried out by the dredger to the disposal place. The proposed model equation was used to formulate the screw propeller specifications considering the resistance to the dredger, and the quantitative specifications of the hydraulic propulsion propeller were determined through the numerical analysis programs. In addition, based on the proposed results, we were able to determine the specifications of the hydraulic system that was used for the hydraulic motor in the propulsion propeller device and then manufactured the hydraulic propulsion propeller. To guarantee the reliability of the proposed model equation, an external testing agency was invited and verified that the hydraulic propulsion propeller based on the proposed model equation could achieve the target speed in the dredger.

• Advances in concrete construction
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• v.12 no.6
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• pp.461-467
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• 2021

Polyethylene-terephthalate (PET) from bottle waste and linear low-density polyethylene (LLDPE) from barrels and tanks waste are widely available and need to be recycled. Recycling them in concrete and mortar is an alternative solution for their disposal. In this study various quantities of sand (5%, 10%, 15% and 20%) were substituted by powder from LLDPE waste. In addition, PET waste fibers (corrugated, straight) were added to the mortar with different percentages (0.5%, 1%, 1.5% and 2%) of cement mass. This paper evaluate the mechanical and physical properties of the composites in fresh (workability, air content and density) and hardened state (compressive and flexural strength, water absorption and total shrinkage). From the experimental results, it can be concluded that the strengthening in tensile of the mortar with plastic waste corrugated fibers is improved. Other important results are that the water absorption and the density rate are less than that of the ordinary mortar.