• Magazine of the Korea Concrete Institute
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• v.9 no.1
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• pp.165-172
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• 1997

Lightweight foamed concrete is a concrete which is lighter than conventional concree by mixing ptetoamed foam in cement slurry. The objectives of this study are to develop optimal prefoarneti lightweight foamed concrete with high lightness. high flowability and enough strength fol special use of structural application by using the polymer foam agent. By mixing the admixtures such as silica-fume and fly-ash and the industrial by-product such as styrofoam for the purpose of practical use of industrial waste, lightweight foamed concrete shich has better lightness. flowability and strength than the conventional prefoamed lightweight foamed concrete is developed. This paper presents extensive data on characteristics of compressive strength and flowability of the concrete manufactured with the different factors in mix design and also presents optimum mix proportion.

• 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 the Korea Institute of Building Construction
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• v.17 no.6
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• pp.493-498
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• 2017

This study is a pioneer investigation to enhance the insulation capacity of the conventional aerated concrete using hydrophobic aerogels. As the main test parameters, aerogel content varied from 0% to 40% of the foam volume. Test results showed that the compressive strength of aerated concrete containing aerogels was lower by 17%~34% than that of the conventional aerated concrete. In addition, the effect of the aerogels on reducing thermal conductivity of aerated concrete is insignificant because of the partial condensation and abnormal distribution of the hydrophobic aerogels. Hence, further hydrophilic treatment for the surface of aerogels is recommended to minimize the decrease in compressive strength and enhance the insulation capacity of aerated concrete.

• Journal of the Korea Concrete Institute
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• v.13 no.1
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• pp.69-76
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• 2001

Foamed concrete for cast-in-site, which shows excellent lightweight, thermal insulation, noise insulation, constructability and cost efficiency, has been applied as thermal insulation or filling material for On-dol. However, the technology is too insufficient to obtain the high level of quality, and serious problems often occur in quality control at sites. It, thus, is necessary to establish the proper and reasonable quality control method for ensuring the required quality, based on the investigation on the physical properties and their reciprocal relation. This study aims to settle the quality control method in case of applying FA foamed concrete replacing 40% by weight with fly-ash as the filling material for On-dol. The results of the study include the correlation among flow, as-placed density and foam ratio of fresh foamed concrete, the correlation between physical properties before hardening and after 28-day, provision of an equation to estimate 28-day compressive strength early with 7-day compressive strength, and suggestion of quality criteria for the revision of KS on foamed concrete for cast-in-site.

• Magazine of the Korea Concrete Institute
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• v.9 no.4
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• pp.125-135
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• 1997

경량기포콘크리트란 시멘트슬러리 속에 미리 생성된 기포를 혼합시켜 양생시킴으써 동일한 체적의 보통콘크리트보다 가볍게 만든 콘크리트를 의미한다. 따라서 경량기포콘크리트는시멘트풀 결합재내에 기포가 무작위로 분포된 복합재료이다. 본 연구의 목적은 이러한경량기포콘크리트의 탄성계수 추정식을 미시역학적 이론을 바탕으로 추정하는데 있다. 이르 위해 본 논문에서는 미시역학적인 미분법에 Hansen의 수정기법을 적용한 수정미분법을 사용하여 경량기포콘크리트의 탄성계수 추정식을 제안하였다. 제안된 추정식을 사용하여 얻어진 결과는 실험결과와 잘 일치하였고 기존의 어떤 추정식보다도 우수한 결과를 보였다.

• Journal of the Korea Institute of Building Construction
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• v.15 no.1
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• pp.1-7
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• 2015

The objective of this study is to develop a high-performance foamed concrete made with a new mixture proportioning as an alternative of autoclaved lightweight concrete (ALC) block. For the early-strength gain of the foamed concrete under an atmospheric curing condition, the binders and chemical agents were specially contrived as follows: 3% anhydrous gypsum was added to ordinary portland cement (OPC) in which $3CaO{\cdot}SiO_2$ content was controlled to be above 60%; and the content of polyethylene glycol alkylether in a polycarboxylate-based water-reducing agent was modified to be 28%. Using these binders and chemical agents, 11 mixes were prepared with the parameters of W/B ratio (30% to 20% in a interval of 2.5%) and unit binder content ($400kg/m^3$ to $650kg/m^3$ in a interval of $50kg/m^3$). The quality and availability of the mixed foamed concrete were examined according to the minimum requirements specified in the KS for ALC block and existed conventional foamed concrete. The measured properties satisfied the minimum requirement of KS for ALC block and proved that the developed high-performance foamed concrete had considerable potential for practical application.

• Journal of the Korea Concrete Institute
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• v.23 no.2
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• pp.151-158
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• 2011

Bubbles within the foamed concrete manufactured by pre-foaming method is the main factor which affects the physical properties of foamed concrete such as density, strength, and porosity. Although many researches on foamed concrete have been continuously carried out, insufficient number of researches on the properties related to bubbles in the foamed concrete has been performed except for chemical application related researches. In order to make an optimal foamed concrete, study on the bubble properties must be pursued. In order to effectively implement bubbles in the manufacturing of foamed concrete, the bubble properties must be estimated. In this study, in order to determine the bubble properties, examination of the bubble properties according to types and foaming agent concentration was performed. An foaming agent used for this test were anionic surfactant, rosin, and protein system with the foaming agent concentration range of 0.05~13%. Test parameters considered in the study were foaming rate, foam volume, drainage solution volume, and bubble size. The study results showed that, regardless of foaming agent type, higher concentration of foaming agent showed an increase in the foaming rate. Also, the results showed that concentration of foaming agent affected bubble size, drainage solution volume change, and bubble distributions. With respect to the stability of the bubble, protein foaming agent was better than anion surfactant or rosin foaming agent. With respect to the bubble shape, anion surfactant and rosin formed bubbles had polygon shape where as protein formed bubbles had spherical shape.

• Journal of the Korea Concrete Institute
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• v.14 no.5
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• pp.742-749
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• 2002

This study was performed to clarify the formation procedure of continuous voids in cellular concrete, and to examine the effect of a foaming agent on the manufacture of cellular concrete with continuous voids. By the experiments, it was determined that cellular concrete to be formed with continuous voids is influenced by temperature, viscosity and flowability of cement paste, and stability of air voids, and is formed in accordance with cohesion of air voids. It was also found that separate voids are formed at an added amount of air voids corresponding to 2 ％ or less of the amount of cement, whereas an antifoaming phenomenon occurs when the added amount of air voids exceeds 9 ％ of the amount of cement. In products with respective cement fineness of 3,000, 6,000, and 8,000㎠/g, a higher compressive strength was exhibited at a higher cement fineness. The continuous void ratio depending on a variation in fineness was 38 ％, 52 ％, and 22 ％ in those products, respectively. That is, a highest continuous void ratio was exhibited at a cement fineness of 6,000㎠/g. When the water-cement ratio was reduced from 45％ to 25％, the compressive strength of the cellular concrete was increased from 15 kgf/㎠ to 20 kgf/㎠ Thus, the reduction in water-cement ratio was effective in achieving an increase in strength without any variation in the specific gravity of the cellular concrete.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.1
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• pp.1-7
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• 2023

A set of foamed concrete specimens with different densities were prepared, and several microscopic techniques, such as scanning electron microscope (SEM) and X-ray micro-computed tomography (micro-CT) were used to characterize the foamed specimens. The pore and solid characteristics of the specimens at different ages were examined to investigate the effect of aging on the materials. The compressive strength and the thermal conductivity of the foamed specimens were also evaluated, and the relationship between the material characteristics and properties was integrated to identify the effect of density and aging on the material properties.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.357-358
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• 2009

Expanded vermiculite and Al powder can produce lightweight porous concrete with excellent insulation performance. From the results, we could find out the possibility to develop environmental-friendly interior materials.