• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.3
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• pp.195-202
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• 2005

This paper presents moment-curvature analytical method of concrete filled steel tubular members considering intensity increase phenomenon by triaxial compression stress generation. For this purpose, this study considers buckling characteristics about compression department of steel members that filled up light weight and normal concrete. The analytical results are compared with the test results. Even if beam that filled up light weight concrete was calculated moment-curvature relationship easily analytically and could know that analytical results estimates as well agreed with the test results in case filled up normal concrete. In addition, the efficiency and applicabilities of the proposed moment curvature relationship algorithm are verified through conventional experimental results.

• Journal of the Korea Concrete Institute
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• v.14 no.2
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• pp.207-215
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• 2002

This study is focusing on mixing the foamed concrete incorporated by waste expanded polystyrene(W-EPS), investigating the physical properties and offering a proper quality control method to the field engineers. Two types of W-EPS (type A and type B) were studied. Type A (B) had globular (crushed) shape and diameter of 3-5 (1-2) mm. The results show that the flow was suddenly reduced with increasing mixing quantity of two types, but it satisfies KS F 4039 until 60 ％ of mixing rate. In general, the absorption rate was suddenly reduced with increased mixing quantity of two types especially, in type A. Apparent specific gravity was 0.36∼0.53 and reduced with increasing mixing quantify of type A. But it increased in case of type B. Compressive strength and heat conduction rate increased with mixing with W-EPS than non-mixing W-EPS but reduced with mixing too much W-EPS. Based ong the results, it is believed that mixing with W-EPS can improve the recycle of industrial wastes and produce the high quality foamed concrete.

• Journal of Energy Engineering
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• v.28 no.1
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• pp.10-16
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• 2019

The purposes of this study is to secure subsidence stability and economical efficiency of lightweight foamed concrete. The composition of lightweight foamed concrete was designed for OPC by substituting with constant contents of calcium sulfaluminate and fly ash. It is found that the flow of lightweight foamed concrete decreased with early ettringite formation by CSA. The initial strength increased with the decrease of drying time of lightweight foamed concrete when CSA was substitution to 10%. The settlement deep of foamed concrete improved the settlement stability by replacing CSA, which prevented shortening of the coagulation time and bubble puffing.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.447-448
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• 2009

On this study, the concrete foaming was maximized using Hydrogen peroxide($H_2O_2$) reciprocal decomposition catalyzed by Manganese dioxide($MnO_2$) and Sodium bicarbonate($NaHCO_3$). Also, we study the physical and mechanical properties of lightweight formed concrete through diverse experiment which is to determine the optimal mixing proportion and require strength of the lightweight formed concrete. As a result of an experiment, it is satisefied with overall quality standard on the KS F 4039 and KS F 2459 provision.

• Magazine of the Korea Concrete Institute
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• v.11 no.2
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• pp.28-32
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• 1999

• Journal of the Korea Institute of Building Construction
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• v.15 no.4
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• pp.383-389
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• 2015

The objective of this study is to develop mixture proportioning approach of crack controlled lightweight foamed concrete without using high-pressure steam curing processes, as an alternative to autoclaved lightweight concrete blocks (class 0.6 specified in KS). To control thermal cracks owing to hydration heat of cementitious materials, 30% ground granulated blast-furnace slag (GGBS) was used as a partial replacement of ordinary portland cement (OPC). Furthermore, polyvinyl alcohol (PVA) and polyamid (PA) fibers were added to improve the crack resistance of foamed concrete. The use of 30% GGBS reduced the peak value of hydration production rate measured from isothermal tests by 28% and the peak temperature of foamed concrete measured from semi-adiabatic hydration tests by 9%. Considering the compressive strength development, internal void structure, and flexural strength of the lightweight foamed concrete, the optimum addition amount of PVA or PA fibers could be recommended to be $0.6kg/m^3$, although PA fiber slightly preferred to PVA fiber in enhancing the flexural strength of foamed concrete.

• Journal of the Korea Institute of Building Construction
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• v.17 no.6
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• pp.507-515
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• 2017

This study is to develop a high quality lightweight foamed concrete that can be applied in the field using EXFG by cracking reducing agent combined with FGD and ALS. First, to increase the volume of foam, the flow and density of the mixture was increased and decreased, respectively. At this time, the effect of substitution ratio of EXFG on fluidity was negligible. The fraction of foam was the highest at EXFG 1%, and the settlement was found to be prevented by the expansion reaction at EXFG 1%. At this time, the ratio of foam was 65%. In the compressive strength, the strengths were similar or decreased when the substitution ratio of EXFG was more than 1%. The apparent density satisfied the KS 0.5 type at the bubble contents was 65%. In case of EXFG substitution, dry shrinkage was decreased by about 10%. As the substitution ratio of EXFG increased, the thermal conductivity increased proportionally.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.853-856
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• 2008

Lightweight foamed concretes are mainly used in apartment building construction for building room floor insulation, sound proof and height difference adjustment, etc. However, existing lightweight foamed concretes have problems like volume reduction by foam removal and excessive crack occurrence, etc, and for compensation, they developed improved concrete binders for lightweight foamed concrete with special characteristics by adding admixture materials used in concrete manufacturing. Therefore, this study reviewed the possibility of its practical use by analyzing all the engineering characteristics after producing imitation member proposed as actual binders and piling lightweight foamed concrete as improved lightweight foamed concrete binder through prior study, the results are as follows. Plain in which various pulverulent materials are mixed showed about 230mm of flow value, satisfying the target flow value, and at 100mm member, about 4mm of settlement occurred, showing a settlement depth reduction effect double the OPC. On strength, OPC showed highest value, but the three levels all showed strengths above the specified value of KS standard 0.5 grade. From the analysis of drying shrinkage member crack, plain, about 0.1mm, was shown very excellent against drying shrinkage crack.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.489-490
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• 2009

In this study, the experiment was carried out to investigate the effect of metakaolin on the compressive strength of lightweight aggregate cellular concrete. For this purpose, five level replacement ratio of metakaolin were selected.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.3
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• pp.247-254
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• 2014

The present study prepared lightweight foam-soil concrete mixtures classified into three groups. Considering the sustainablility, workability, and compressive strength development of such concrete, high-volume supplementary cementitious materials (SCMs) were used as follows: 20% cement, 15% fly ash, and 65% ground granulated blast-furnace slag. As main test parameters selected for achieving the compressive strength of 1MPa and dry density of $1,000kg/m^3$, the unit solid content (dredged soil and binder) ranged between 900 and $1,807kg/m^3$, and soil-to-binder ratio varied between 3.0 and 7.0. Test results revealed that the flow of the lightweight foam-soil concrete tended to decrease with the increase of unit soil content. The compressive strength of such concrete increased with the increase with the unit binder content, whereas it decreased as soil-to-binder ratio increased, indicating that the compressive strength can be formulated as a function of its dry density and soil-to-binder ratio.