• Computers and Concrete
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• v.16 no.6
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• pp.909-918
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• 2015

This paper presents an experimental study for determining the bond performance of lightweight concretes produced using pumice aggregate coated with colemanite-cement paste. For this purpose, eight hinged beam specimens were produced with four different concrete mixtures. 14 mm deformed bars with $10{\Phi}$ development lengths were selected constant for all test specimens. All the specimens were tested in bending and load-slip values were measured experimentally to determine the effect of colemanite-cement coated pumice aggregate on bond performances of lightweight concretes. Test results showed that, colemanite-cement coated pumice aggregate increases compressive strength and bond performance of the lightweight concretes, considerably.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.151-156
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• 2001

Concrete has excellent characteristics as building material and functions relatively well; but it has many problems concerning too heavy weight of the structures. Accordingly, it is the assignment for study in the part of building materials to lighten and high strengthen the weight of concrete structures in order to improve those weak Points; and it seems one of the representative solutions to develop the high strength lightweight aggregate concrete. Based on the experimental results presented, the following conclusions are drawn. The concrete with unit weight of 1.96~2.03t/$m^{2}$, compressive strength of 322~431kgf/$cm^{2}$ was gained. So, it appears that the lightweight aggregate concrete will be useful for low unit weight and high strength lightweight aggregate concrete. In the end, to manufacture artificial lightweight aggregate concrete for construction work is necessary to develope artificial aggregate which has improved performances physically.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.5
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• pp.474-479
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• 2013

Mass reduction of the machine tool movable parts is a tool for achieving lower energy demands of the machine tool operation. The realization of lightweight design in machine tool can be achieved by structural lightweight design and material lightweight design. In this study, topology optimization strategy was applied to design optimized structures of movable parts of 5 axis machining center. The weight of ram which has most significant influence on the stiffness of whole machine tool was reduced without stiffness deterioration. The redesigned optimized ram has 24.2% less weight while maintaining the same displacement caused by cutting force.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.293-298
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• 1995

The strength of shear connectors embedded in lightweight concrete slab with deck plate is influenced by various factors of deck plate, shear conncetor and concrete. Generally, it is reported that the strength of shear connector in lightweight concrete decreases in comparison with that in normal concrete. So this paper is to use compressive strength of lilghtweight concrete, width-height ratio of deck plate, and cross sectional area of shear conncetor as variables, to evaluate the strength of shear conncetors in composite beam of steel and lilghtweight concrete slabs with deck plate, and then to suggest the reasonable strength equation by comparing the push-out test results with establixhed strength formula. As the result of 24 specimens test, in case of lightweight concrete slab with deck plate, it has showed that in the same strength, the strength of shear connector decreased about 10~20% in comparison with that in normal concrete. In spite of lightweight concrete, the test results were closely approached the established strength formula of shear connector using Fisher's reduction coefficient.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.684-687
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• 2004

The purpose of this study is to obtain basic data on the properties of the development of lightweight mortar contained foam agent for various applications in the field. In the experiment, as a result of measurement the specific gravity by the change of the W/C and the foam agent into a variable and measuring the compressive strength of mortar, specific gravity checked that a compressive strength therefore increased. Mortar is using lightweight foam agent having the change of specific gravity, the water cement ratio $50\%,\;40\%,\;30\%$. This paper present extensive data on the characteristics of strength of the lightweight mortar and also presents the mechanical characteristics of the lightweight according to specific gravity.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.204-207
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• 2004

In this paper, mechanical properties of the high strength lightweight self-compacting concrete with simple mixed design method was investigated. Experimental tests were performed as such compressive strength, splitting tensile strength, modulus of elasticity and density of high strength lightweight self-compacting concrete. The 28 days compressive strength of high strength lightweight self-compacting concrete with the LC replacement ratio of $100\%$ reduces about $31\%$ but LF replacement ratio of $100\%$ increase about $20\%$ compared that of the control concrete. The structural efficiency of high strength lightweight self-compacting concrete increase with proportional to the replacement into of LF. The relationship between the splitting tensile strength and 28 days compressive strength can be represented by the equation $f_s=0.076f_{ck}+0.5582$. The modulus of elasticity was found to be lower than that of normal weight concrete, ranging form 24 to 33 GPa.

• Journal of the Korean Society for Advanced Composite Structures
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• v.7 no.1
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• pp.1-8
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• 2016

In this paper, the full-size structural performance test for a lightweight soundproof tunnel composed of partitioned pipe truss members is carried out to investigate the structural performance. In addition, a nonlinear structural analysis of the same finite element model as the full-size testing model is performed to compare the test result. The test and analysis results showed that the lightweight soundproof tunnel ensures the structural safety against wind loads, snow loads and load combinations. As a result, the full-size test and analysis results meet all the design load conditions, hence the proposed lightweight soundproof tunnel is ready for the field application.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.2
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• pp.63-72
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• 2005

In this study, the physical and mechanical properties of steel fiber reinforced lightweight polymer concrete were investigated experimentally with various steel fiber contents. All tests were performed at room temperature, and stress-strain curve and load-deflection curve were plotted up to failure. The unit weight of steel fiber reinforced lightweight polymer concrete was in the range of $1,020{\sim}1,160\;kg/m^3$, which was approximately $50\%$ of that of the ordinary polymer concrete, The compressive strength, splitting tensile strength, flexural toughness and flexural load-deflection curves after maximum load were shown with increase of steel fiber content. The stress-strain curves of steel fiber reinforced lightweight polymer concrete were bilinear in nature with a small transition zone, Based on these results, steel fiber reinforced lightweight polymer concrete can be widely applied to the polymer composite products.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.189-192
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• 2001

This study is peformed to develop high strength lightweight concrete using synthetic lightweight coarse aggregate. The following conclusions are drawn; The unit weight is in the range of $1,855{\sim}1,883kgf/m^{3}$, which has showed about 75% that of normal cement concrete. The compressive strength is in the range of $240{\times}249kgf/cm^{2}$, the tensile strength is in the range of $30{\sim}33kgf/cm^{2}$ and the bending strength is in the range of $41{\sim}50kgf/cm^{2}$ at the age 7days. The high strength lightweight concrete which is contained fly ash within 10% is showed highest strength.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.825-830
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• 1999

The purpose of this study is to improve overall performance of prefoamed lightweight cellular concrete for On-Dol system floor. This study includes 4 sections as follows. \circled1 Analysis of the structural characteristics of On-Dol System focusing on the lightweight cellular concrete insulation layer. \circled2 Establishment of the mixing design equations. \circled3 Development of some admixtures used with foaming agent. \circled4 Improvement of the equipment for onsite production. This study has proven that, compared with the current existing one, the newly developed lightweight cellular concrete has been reduced the usage of cement by 20% and the cracks caused by cement drying shrinkage up to 80% but has shown the increased compression strength by 20% at 7 days curing period. The volume contraction of freshly prepared cellular concrete by the loss of foam was hardly found in newly developed lightweight cellular concrete.