• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.849-852
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• 2006

The lightweight foamed concrete is superior to properties of insulation and light-weight because it is included in many inner pore. So, lightweight foamed concrete used to construction field that need to property of insulation. The property of insulation of lightweight foamed concrete is varied with density. Also, Density is varied with hardening matrix and pore rate. The purpose of the experiment is to know thermal properties of specimen according to the change of density when heating the specimen. As a result of this experiment, the higher density, the lower temperature of mold. this tendency isn't same as ordinary lightweight foamed concrete, and then density 0.9 is expressed most low temperature result also the discontinuity of shape of mold was efficient for the prevention of the temperature rise.

• Structural Engineering and Mechanics
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• v.42 no.1
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• pp.73-93
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• 2012

With an active structural involvement in spiral case structure (SCS) that is always the design and research focus of hydroelectric power plant (HPP), the compressible membrane sandwiched between steel spiral case and surrounding reinforced concrete was often assumed to be linear elastic material in conventional design analysis of SCS. Unfortunately considerable previous studies have proved that the foam material serving as membrane exhibits essentially nonlinear mechanical behavior. In order to clarify the effect of membrane (foam) material's nonlinear stress-strain behavior on SCS, this work performed a case study on SCS with a compressible membrane using the ABAQUS code after a sound calibration of the employed constitutive model describing foam material. In view of the successful capture of fitted stress-strain curve of test by the FEM program, we recommend an application and dissemination of the simulation technique employed in this work for membrane material description to structural designers of SCS. Even more important, the case study argues that taking into account the nonlinear stress-strain response of membrane material in loading process is definitely essential. However, we hold it unnecessary to consider the membrane material's hysteresis and additionally, employment of nonlinear elastic model for membrane material description is adequate to the structural design of SCS. Understanding and accepting these concepts will help to analyze and predict the structural performance of SCS more accurately in design effort.

• Computers and Concrete
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• v.33 no.3
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• pp.241-250
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• 2024

This article investigates the thermal and post-buckling problems of graphene platelets reinforced metal foams (GPLRMF) beams with initial geometric imperfection. Three distribution forms of graphene platelet (GPLs) and foam are employed. This article utilizes the mixing law Halpin Tsai model to estimate the physical parameters of materials. Considering three different boundary conditions, we used the Euler beam theory to establish the governing equations. Afterwards, the Galerkin method is applied to discretize these equations. The correctness of this article is verified through data analysis and comparison with the existing articles. The influences of geometric imperfection, GPL distribution modes, boundary conditions, GPLs weight fraction, foam distribution pattern and foam coefficient on thermal post-buckling are analyzed. The results indicate that, perfect GPLRMF beams do not undergo bifurcation buckling before reaching a certain temperature, and the critical buckling temperature is the highest when both ends are fixed. At the same time, the structural stiffness of the beam under the GPL-A model is the highest, and the buckling response of the beam under the Foam-II mode is the lowest, and the presence of GPLs can effectively improve the buckling strength.

• Journal of the Korean Geosynthetics Society
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• v.3 no.2
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• pp.3-11
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• 2004

Fabric Foam systems provide a variety of flexible bank protection for open channels and hydrulic structures. The structural performance and durability of conventional bank protection materials such as concrete, gravel, riprap and vegetation can be significantly improved by confining the materials within the cells of Fabric Foam system. This paper presents the results of field and laboratory tests carried out to evaluate the performance of new Fabric Foam System as a Bank Protection. The results of the tests confirmed effect of Fabric Foam System in Bank Protection.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.913-918
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• 2001

This paper investigates insulating effects and strength properties of concrete under cold climate carrying out the experiment with insulating forms on the slab member. According to test results, under $-10^{\circ}C$ of outer temperature, the surface of concrete exposed to outer temperature goes below zero after 10hours since exposed. And, the surface of concrete covered with vinyl and blanket goes below zero after 42hours. However, the surface of concrete covered with insulating materials such as polystyrene foam does not drop below zero until 55hours. And, according to coring sample strength test, compressive strength cured with insulation shows much higher strength than no insulation curing condition and vinyl and blanket curing condition.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.21-22
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• 2018

Foamed concrete is a porous concrete that is cured by mixing bubbles into cement slurry. It is lighter than ordinary concrete and is characterized by higher insulation. Lightweight foamed concerte is mainly used as a sandwich panel in Korea, and is also used as a refractory filler in fireproof safes. Studies on lightwight foamed concrete have been carried out on strength,density and thermal conductivity. However, it is confirmed that the research on the fire resistance performance is very limited. Based on this study, fire resistance of lightweight foamed concrete using expanded polystyrene beads is investigated.

• Computers and Concrete
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• v.20 no.6
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• pp.689-704
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• 2017

The paper presents experimental and numerical investigations of prefabricated composite structural building reinforced concrete slabs with the insulating material for a residential building construction. The building slabs were composed of concrete and expanded polystyrene. In experiments, the slabs in the full-scale 1:1 were subjected to vertical concentrated loads and failed along a diagonal shear crack. The experiments were numerically evaluated using the finite element method based on two different constitutive continuum models for concrete. First, an elasto-plastic model with the Drucker-Prager criterion defined in compression and with the Rankine criterion defined in tension was used. Second, a coupled elasto-plastic-damage formulation based on the strain equivalence hypothesis was used. In order to describe strain localization in concrete, both models were enhanced in the softening regime by a characteristic length of micro-structure by means of a non-local theory. Attention was paid to the formation of critical diagonal shear crack which was a failure precursor.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.449-452
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• 2005

Sound absorption coefficient is affected by void in sound absorbing materials, therefore it is important to analyze properties of void pore. Also, it can be used to estimate performance of foamed concrete when it is applied to absorb sound. The purpose of this study is to analyze the sound absorption coefficient and void characteristic of foamed concrete using bottom ash. As a result of experiment, it was determined that an increase in sound absorption coefficient is achieved by increasing added amount of foam.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.457-460
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• 2005

The stone powder sludges, which are occurred in aggregate production company, have classified the specified waste, so taking place the environment pollution and the disposal cost. In this causes, the stone powder sludge is required the development of recycling technique. This study concerned with the using possibility of stone powder sludge on light weight concrete. We acquired the fundamental date on recycling technique of stone sludges, by hydro-thermal reaction. The results shows that it is possible to develop the light weight concrete, having various range of properties according to the content of foam.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.77-78
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• 2019

Organic insulating materials can cause fatal toxic gases when burned, which can lead to human injury. As a combustible material, the risk of fire spreading is great. Therefore, there is a need for a study on the lightweight cured body for the non-combustible inorganic insulation to replace the flammable organic insulation. This study aims to examine the properties of lightweight foamed concrete according to the dilution concentration of animal foaming agent which forms a closed void when foaming as a part of the experiment to examine the utility of the lightweight foamed concrete as an insulating material. Bubbles occupy a large volume of lightweight foam concrete and have a great influence on the properties. Therefore, the stability of the bubble is very important, and as a result of the experiment, it is determined that 3% of the smallest vesicles are prepared at the proper dilution concentration.