• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.1
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• pp.83-91
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• 2012

In this study, the compressive strength characteristics of lime-cement-soil mixtures, composed of lime, soil, and a small amount of cement, were investigated by performing the unconfined compression tests, the freezing and thawing tests, the wetting and drying tests and the permeability tests. The specimens were made by mixing soils with cement and lime. The cement contents were 0, 6, 8 and 10 %, and the lime contents were 2, 4, 5, 10, 15 and 20 % in weight. Each specimen was cured at constant temperature in a humidity room for 3, 7 and 28 days. The compressive strength characteristics of the lime-cement-soil mixtures were then investigated using the unconfined compression tests, freezing and thawing tests and the wetting and drying tests. Based on the test results, a discussion was made on the applicability of the lime-cement-soil mixtures as a construction material.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2153-2162
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• 2011

The goal of this Paper is to reduce rail's wear in curved track by applying an additional surface layer material(High hardness and High resistance capacity of wear) on the top of the railhead. In order to evaluate appropriation of a coating material, experimental tests such as the varieties of fundamental properties tests (hardening, wear, tensile, and bending) and RCF(rolling contact fatigue)test were performed to establish fatigue wear and damage mechanism. As a result, wear performance of coating rail is better than heated rail about 6times and normal rail about 8~9times.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.207-213
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• 2001

Shaking table tests to investigate the dynamic friction behavior of interfaces between dense dry granular soils and construction material(concrete) were performed and the results are reported. The results show the variation of dynamic interface friction coefficients between dense dry granular soils and construction material was small in the sliding velocity range employed in this study. It was also observed that dynamic interface friction coefficients decreased as mean grain sizes of granular soils increased. These coefficients were compared with the friction coefficients obtained from the peak internal friction angles of the same granular soils by plane strain compression tests.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.189-194
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• 1995

This paper presents the material properties and production of 500 and 700 kg/$\textrm{cm}^2$ high strength concrete for the practical utilization. A series of Lab. tests were conducted to optimize the material mixture of high strength concrete and then mock-up tests were performed through the Remicon Batch Plant. This paper stresses the material conditions for the final stage of production of 500 and 700 kg/$\textrm{cm}^2$ high strength concrete, just prior to the practical use on 28-story Samsung Shin-Daebang Housing-Commercial Combined Building with 8-story basements.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.602-607
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• 1998

Rubber materials are extensively used in various machine design application, mainly for vibration/shock/noise control devices. Over the years an enormous effort has been put into developing procedures to provide properties of rubber material for design function. However, there are still a lot of difficulties in the understanding of dynamic characteristics of the rubber components in compression. In this paper, the dynamic characteristics of rubber materials for anti-vibration under compression were investigated. Dynamic and static tests for rubber material with 3 different hardness were performed. In dynamic tests, non-resonance method, impedance method, was used to obtain the complex modulus (storage modulus and loss factor) and the effects of static pre-strain on the dynamic characteristics were investigated. Also, a relation equation between linear dynamic and nonlinear static behavior of rubber material was discussed and its usefulness to predict their combined effects was investigated.

• Journal of Korean Association for Spatial Structures
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• v.2 no.3 s.5
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• pp.103-113
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• 2002

This thesis investigates vibration response characteristics of building frames in which dampers are installed. The frames belong to passively vibration-controlled. Structures which utilizes energy dissipation of mechanical dampers provided in the structure. In this thesis, a turbulent flow damper sealed by visco-elastic material was dealt with as the device of passive vibration control. To investigate the resisting force characteristics of the damper, harmonic vibratration tests were carried out. Based on the test results, a theoretical model of the damper resistance was presented and a method of identifying the model parameters was proposed. Shaking table tests of the frame with and without the dampers were carried out and the effectiveness of the damper was examined. The response of the frame with the dampers was reduced to 1/2 or 1/3 of the cases without the damper.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1068-1075
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• 2006

Flow-able backfill is known as soil-cement slurry, void fill, and controlled low-strength material (CLSM). The benefits of CLSM include reduced equipment costs, faster construction, re-excavation in the future, and the ability to place material in confined spaces such as narrow parts nearly impossible for compaction or perimeter of underground power cables. A review of some recent full-scale tests carried out by KEPRI on slurry backfill materials for application in underground power cable was presented. Based on this research, applicability was assessed and compare to results of laboratory tests for improved slurry materials with optimal mixture contents.

• Journal of Ocean Engineering and Technology
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• v.9 no.1
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• pp.132-141
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• 1995

The purpose of the present study is to investigate the statistical characteristics of m and C in the fatigue crack propagation law, da/dN=C(.DELTA.K)/sup m/ and to studies on the randomness of fatigue crack propagation and retardation behavior. Fatigue tests were perfomed on 32 CT specimens of SPV50 steel under the same one condition. First, the value of m and C were determined for each specimen, and all the data were analyzed statistically. second, the material's resistance to fatigue crack propagation is modeled as a stchastic process, which varies randomly along the crack path. The statistical analysis of the material resistance is performed with the data obtained by constant load controlled tests. Finally, retardation behavior was examined experimentally by using a CT specimen, and a retardation parameters were analyzed statistically.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.552-557
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• 2001

Copper slag is the by-producted material on the proceeding of refining the copper. To verify applications of copper slag to vertical drain material can substitute for the sands in ground improvement, laboratory soil tests and consolidation model tests were conducted. The results of consolidation model test was analyzed as the hyperbolic method. The hyperbolic method assumes that the settlement(s) versus time(t) behavior approaches a straight line describes a hyperbolic reaction. The inverse of the slope of the line would then yield the ultimate settlement. Through in this study, copper slag is compatible with vertical drain material as like sands. Copper slag compaction pile promote the consolidation settlement.

• Smart Structures and Systems
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• v.6 no.9
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• pp.1041-1056
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• 2010

This paper investigates the possibility of a strategy for an automatic full recover of a structural component undergoing loading-unloading (fatigue) cycles: full recover means here that no replacement is required at the end of the mission. The goal is to obtain a material capable of self healing earlier before the damage becomes irreversible. Attention is focused on metallic materials, and in particular on shape memory alloys, for which the recovering policy just relies on thermal treatments. The results of several fatigue tests are first reported to acquire a deep understanding of the physical process. Then, for cycles of constant amplitude, the self-healing objective is achieved by mounting, on the structural component of interest, a suitable microcontroller. Its input, from suitable sensors, covers the current stress and strain in the alloy. The microcontroller elaborates from the input the value of a decisional parameter and activates the thermal process when a threshold is overcome.