• Journal of the Korean Ceramic Society
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• v.45 no.8
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• pp.443-452
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• 2008

Shrinkage crack is a major concern for cement materials, especially for flat structures such as Korean On-Dol floor system, flooring for garages, and wall. One of the methods to reduce the adverse effects of shrinkage cracking is to reinforce cement materials with shot randomly distributed fibers. The efficiency of inorganic fibrous material to arresting cracks in cementitious composites was studied. Cement materials reinforced with five different qualities of inorganic fibrous material were tested. Contents of inorganic fibrous material were 1.0 kg, 1.5 kg, 2.0 kg, 2.5 kg, 3.0 kg by weight of cement mortar and C : S types of cement mortar were 1:3 and 1:4. W/C were 60% and 80%. Cement mortar of inorganic fibrous material reinforcement showed an ability to reduce the crack width and crack length significantly as compared to unreinforced cement mortar. $40%{\sim}60%$ drop in shrinkage crack of 1:4 cement mortar with 1.5 kg over was observed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.4 no.1
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• pp.131-138
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• 2000

In this study, physical and engineering properties of ordinary portland cement and microcement were investigated to verify reinforcing effect of underpinning of open caisson foundation by using microcement grouting. Laboratory injection tests such as infiltration and injection in case of seepage for the stream bed soil at ${\bigcirc}{\bigcirc}$ Great Bridge in Seoul were carried out. Field injection tests to reinforce open caisson foundation at ${\bigcirc}{\bigcirc}$ Great Bridge were performed and the ability of application by microcement grouting was evaluated. From the test results, physical and engineering properties of microcement are better than those of ordinary portland cement. Also, the ability of infiltration and solidity in case of seepage is better than that of ordinary portland cement. Therefore, it is concluded that microcement is an excellent material to reinforce open caisson foundation of the existing bridge structure under the water and can be used as underpinning material of general foundations.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.81-84
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• 2002

An approach for predicting the effective thermal conductivities of fiber-reinforce composite has been developed based on a thermal-electrical analogy. The unit cell of the composite laminate is divided into regular volume elements and the material properties have been given to each element. By constructing the series-parallel thermal resistance network, the thermal conductivities of composite both in-plane and out-of-plane direction have been predicted. Graphite/Epoxy composite is used for a balanced plain-weave composite laminate. By comparing the predicted results and the previous works, good agreement has been found.

• Advanced Composite Materials
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• v.16 no.4
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• pp.349-360
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• 2007

Recently, natural fiber reinforced composite is attracting attention and considered as an environmentally friendly material. Usually cellulosic fibers are used to reinforce the composites, but some protein fibers such as silk and wool serve the same purpose. In this paper, we proposed a method of producing artistic composite from artistic fabric by using silk fiber reinforced biodegradable plastic, which is designated as 'silk composite', for reinforcement. In order to expand applications of the silk composite, we performed the compression molding of decorative laminates with woody material, which was selected as a core material, and examined the properties of molded decorative laminates with various content of the silk composite. Since plywood and medium-density fiberboard (MDF) are widely used for decorative laminates, we selected them as core materials. As a result, flexible decorative laminates with high flexural strength were obtained by compounding the silk composite with wood materials.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.249-250
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• 2018

To control the floor noise generated in the apartment building, a method of reinforcing the floor at the floor is applied. However, since existing buildings are difficult to reinforce upper generations, the ceilings of lower generations should be reinforced. The purpose of this study is to analyze the reduction effect by measuring the impact noise after reinforcing the floor soundproofing material on the ceiling of the existing building. In order to ensure the economical efficiency and flame retardancy of the products used as building interior materials, the existing polyurethane foam was impregnated with mineral to prepare test specimens and attached to the concrete slab surface. As a result, it was shown that heavy impact sound can reduce 2dB~5dB and light impact sound can reduce 4~8dB.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.475-478
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• 1999

A numerical tool for predicting the behavior of reinforced concrete structures under uniaxial loads is proposed. Concrete is considered as quasi-brittle material, and for a reinforcing bar, an elastic-perfectly plastic constitutive relationship is adopted. In this study, the behavior of reinforced concrete according to the interface properties between the concrete and steel is analyzed. Comparisons between the numerical predictions and the experimental results show good agreements in the load-deflection behaviors and ultimate loads of reinforced concrete structures.

• Journal of Family Resource Management and Policy Review
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• v.15 no.3
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• pp.23-42
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• 2011

This study proposes a plan for the residents to have a capacity to build a family-friendly community on their own. As there is not a family-friendly community related program developed for "Resident's Capacity Reinforcement", three programs closely related with family-friendly community program were analyzed instead. Analysis showed that first, the community spirit must be emphasized to maintain the characteristics of family care with social support. Second, educational contents must reflect resident's capacity elements that are necessary for participating in the family friendly community building stages. Third, there is a necessity for systematization of education courses into beginner, intermediate, and specialty course given education is continued. Fourth, there is a necessity for the curriculum that may be used for the family friendly community building to foster human and material resource management ability. Therefore, framework for the educational contents suggests X-axis and Y-axis presented by person-business and morphogenic-morphostatic as referred to Ulrich(1997),s human resource model. However, this study has limitations because educational program of 'livable community building' are analyzed for the plan to reinforce capacity to build family-friendly community. There is a necessity for continuing to improve the program by in depth interview or social survey with residents and leader in community.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.352-361
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• 2006

The grouting method is widely used in construction to reduce permeability and reinforce the ground. If the cement and grout material are not mixed well in the injection tip equipment, an opposite flow and Interception state of the chemical grouting can occur. McG method installs a special grouting device to allow better mixing of the grouting material and prevent backward flow. The block of nozzle also diversify powder rate of cement. YSS that lowers $Na_2O$ and thereby increases durability is developed by gel-forming reaction material. In this study, the seepage state and unconfined compressive strength of the injection material using the special injection tip equipment is tested. The results of laboratory and field tests clearly demonstrate that the strength increases and permeability decreases using the McG method.

• Journal of the Korean Geosynthetics Society
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• v.8 no.2
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• pp.11-20
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• 2009

This study, as basic research which was intended to develope the surface reinforcement method using reinforcement material which is applicable to very soft ground in Korea, was aimed at proposing the design parameter for the surface ground improvement method. To that end, a wide width tensile test using geotextile, geogrid and steel bar (substitute for bamboo) and 21 kinds of the laboratory model tests with the end restraint conditions of the reinforcement that comprises the constrained and partially constrained (3 types) conditions were conducted. Moreover, a new procedure was proposed to take into account the effect of the stiffness of Reinforce materials on bearing capacity theory of Surface Reinforcement Method for Soft Ground.

• Journal of the Korean Wood Science and Technology
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• v.11 no.3
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• pp.31-38
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• 1983

This experiment was carried out to improve the physical and mechanical properties of sawdust-board by combining with reinforce material, that is, plastic wire screen and steel wire screen. In experiment results, the density of sawdust-board reinforced with three steel wire screens was highest and its bending strength was also highest. Wastepaper-5% mixed sawdust-board showed as high bending strength as other boards, and therefore the possibility of using wastepaper as raw materials for boards. The sawdust-board with steel wire screen was not ruptured immediatedly after having been deformed by static loading. However, plywood showed higher bending strength than the reinforced sawdust-boards.