• International Journal of Concrete Structures and Materials
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• v.5 no.2
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• pp.125-131
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• 2011

Five all-lightweight alkali-activated (AA) slag concrete mixes were tested according to the variation of water content to examine the significance and limitation on the development of cementless structural concrete using lightweight aggregates. The compressive strength development rate and shrinkage strain measured from the concrete specimens were compared with empirical models proposed by ACI 209 and EC 2 for portland cement normal weight concrete. Splitting tensile strength, and moduli of elasticity and rupture were recorded and compared with design equations specified in ACI 318-08 or EC 2, and a database compiled from the present study for ordinary portland cement (OPC) lightweight concrete, wherever possible. Test results showed that the slump loss of lightweight AA slag concrete decreased with the increase of water content. In addition, the compressive strength development and different mechanical properties of lightweight AA slag concrete were comparable with those of OPC lightweight concrete and conservative comparing with predictions obtained from code provisions. Therefore, it can be proposed that the lightweight AA slag concrete is practically applicable as an environmental-friendly structural concrete.

• Korean Journal of Computational Design and Engineering
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• v.18 no.4
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• pp.299-307
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• 2013

Introduction of PLM in domestic shipyards is being retarded as ship PLM has yet to firm up return of investment and process integration. To implement a ship PLM system, it is required to share ship CAD model data in various design and manufacturing environments. Lightweight CAD models provide a promising solution for sharing CAD models in the product life cycle, which can expedite implementation of ship PLM in domestic shipyards in the near future. Compared to proprietary CAD models, it is easy for lightweight CAD models to be interfaced with various application systems and be connected to manufacturing information. In this paper, the reason why lightweight CAD models are necessary to implement a ship PLM system is addressed and current implementation results are introduced.

• 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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• 1997.10a
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• pp.393-400
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• 1997

It is possible to reduce dead load and cross section of structural members by use of lightweight concrete, and also reduce the cost of construction. The mechanical properties of lightweight concrete are lower than that of normal weight concrete having the same compressive strength, then it is necessary to make higher strength of lightweight concrete for structural use, and the objective of this paper is to development and application the highstrength lightweight concrete with lower than 2.0t/$\textrm{m}^3$ of unit weight and over than 350kg/$\textrm{cm}^2$ of compressive strength.

• International Journal of Highway Engineering
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• v.15 no.5
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• pp.57-64
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• 2013

PURPOSES : It is to evaluate lightweight soil as a subgrade material based on mechanical tests and calculation of pavement performance. METHODS : In this research, various contents of cement and air foam are used to make lightweight soil using wasted dredged soil. Uniaxial compressive strength test is conducted to evaluate strength of 7 and 28 day cured specimens. Secant modulus was calculated based on the stress and strain relationship of uniaxial compressive strength test. Resilient modulus test was measured using by repeated triaxial compression test. The measured resilient modulus was used in layered elastic program to predict fatigue and rutting life at a given pavement structure. RESULTS : Uniaxial compressive strength increases as cement content increases but decrease as air foam content increases. Resilient modulus also increases as cement content increases and decrease as air foam content decrease. CONCLUSIONS : It is concluded that dredge clay soil can be used as subgrade layer material using by lightweight treated soil method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.6
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• pp.112-121
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• 2013

FRP reinforced lightweight concrete structures can offer corrosion resistance and weight reduction effect simultaneously, so practical use of the structures may be expected afterwards. But to make concrete structures using lightweight concrete and FRP bar, that can resist external forces without internal slip of the FRP bar, it is very important to understand bond characteristic between lightweight concrete and FRP bar. During that time, a lot of studies for bond behaviors of FRP bar in normal concrete were conducted, but studies for bond behavior of FRP bar in lightweight concrete are very limited to date. So, bond characteristic between lightweight concrete and helically deformed GFRP bar was investigated in this study. Three main parameters were considered in experimental investigation: type of rebar, concrete type, and compressive strength of lightweight concrete. As an experimental result, it could be known that bond strength of helically deformed GFRP bar in lightweight concrete was 0.49 times bond strength of steel reinforcement in normal concrete.

• Journal of the Korea Institute of Building Construction
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• v.7 no.2 s.24
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• pp.77-83
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• 2007

This study investigated the fundamental properties of the lightweight foamed concrete depending on various admixtures, and the results were summarized as following. When 20% of cement kiln dust(CKD) and 0.002% of stabilizing agent were mixed to lightweight foamed concrete, it was necessary to use a superplasticizer because flowability was decreased. However, it could reduce sinking depth which were the extensive trouble of lightweight foamed concrete. Bulk density was divided into '0.4' and '0.5' grades on KS according to unit volume weight. The compressive strength was less than that of plain concrete when admixtures were applied, but the results exceeded the minimum strength of the each grades on KS. Totally, it is found that the combination of 20% of CKD and 0.002% of stabilizing agent makes it possible to reduce a sinking depth, recycle resources, and save cost when were mixed.

• Computers and Concrete
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• v.14 no.3
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• pp.233-245
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• 2014

In this paper, a rule based Mamdani type fuzzy logic model for prediction of slippage at maximum tensile strength and slippage at rupture of structural lightweight concretes were discussed. In the model steel rebar diameters and development lengths were used as inputs. The FL model and experimental results, the coefficient of determination R2, the Root Mean Square Error were used as evaluation criteria for comparison. It was concluded that FL was practical method for predicting slippage at maximum tensile strength and slippage at rupture of structural lightweight concretes.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.327-332
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• 2000

The objective of this study was to improve the defects of lightweight cement concrete by treating with redispersible polymer powders. The statistical relationships of water-cement ratios, contents of lightweight aggregates and polymer powers and be used for predicting the concrete strength. It was found that the varieties and techniques adopted in this experiment were capable of identifying the influence of various tested for air contents, flow test, water absorption, specific gravity, flexural and compressive strength. This study showed that fundamental properties were very affected by cement- lightweight aggregate ratio, polymer-cement ratio and water-cement ratio.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.250-251
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• 2017

In study, the lightweight insulation mortar is produced with more than 50,000tons of waste each year, but it is difficult to treat with the degradable composite material and the recycling ratio is still 50%. the lightweight insulation mortar is manufactured by using the ratio of expanded polystyrene and pulverized expanded polystyrene.