• Journal of the Korean GEO-environmental Society
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• v.22 no.12
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• pp.59-63
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• 2021

This study presented the characteristics and additive effects of the grout with mixing ratio for developing of high-efficiency grouting technology under high depth conditions. The laboratory investigation were conducted with Portland cement (OPC) and micro cement (S8000-E) including viscosity experiments, particle size analysis experiments, Gel-Time experiments and uniaxial compressive strength experiments. As a result of the viscosity experiment, it was shown that OPC is advantageous in terms of viscosity, but S8000-E is suitable when considering the passage of rock joint intervals through particle size analysis. The Gel-Time experiment shows that it is not that difficult with injection as a grout material even when silica fume (SF) was applied. The strength of the cured material is improved as increase in the content of silica fium (SF). Within the range of the study, the optimal mixing ratio obtained through various experiments is S8000-E, w/c=70%, silica fium (SF)=6%, and 7 days.

• Resources Recycling
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• v.21 no.3
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• pp.39-47
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• 2012

This study was conducted to optimize a mixing design of lightweight aerated concrete with the blast furnace slag(BFS) using Box-Behnken method, one of response surface designs. The lightweight aerated concrete with the BFS was made on the conditions of steam curing method at atmospheric pressure. The experimental factors were unit Water(W)/total powder($P_d$) ratio, BFS replacement percentage and Al powder addition based on the total powder (${P_d}^*$%). From the results of the response surface analysis, regression models for dried specific gravity and compressive strength of the lightweight aerated concrete were derived. When the target values for dried specific gravity and compressive strength of the lightweight aerated concrete were set at 0.72 and 4.42 MPa respectively, its optimized mixing conditions driven from the regression models were 0.62 of $W/P_d$ ratio, 35.5% of BFS replacement and 0.05% of Al powder addition. This experimental design model was found to be credible by measuring the dried specific gravity and compressive strength of the sample made from the above mixing conditions.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.10a
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• pp.291-294
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• 2010

EPS 샌드위치 패널은 화재 시 치명적인 단점을 가지고 있다. 하지만 여전히 EPS 샌드위치 패널이 국내에 많이 사용되는 이유는 가격이나 시공성, 생산성에서 EPS를 대체할만한 물질이 아직 개발되지 않는 실정이다. 글라스 울 패널과 우레탄 폼 패널이 시장에 조금씩 유통되고 있지만 여전히 EPS 패널이 시장에서 70%이상을 차지하고 있다. 그래서 EPS를 코팅, 함침, 주입 등의 여러 가지 방법도 개발되고 있으나 그 중 가장 간단하고 가격이 낮고, 샌드위치패널에 적용이 가능한 코팅법에 의한 난연제의 배합설계와 비드와 난연제의 난연 등급에 따른 최적의 배합비를 제안하고자 한다.

• Food Science and Preservation
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• v.10 no.3
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• pp.308-313
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• 2003

In the present study, we investigated the optimum recipe of the pumpkin drink using old pumpkin extract. Response surface methodology (RSM) was applied to optimize and monitor the drink recipe with pumpkin extract. The polynomial equation for color, flavor, taste, mouth feel, overall palatability, pH, brix and viscometer showed 0.7682, 0.9046, 0.9364, 0.9110, 0.8456, 0.9264, 0.7135 and 0.9906 of R$^2$, respectively and flavor, taste, mouth feel, overall palatability, pH and viscometer showed 5～10％ of significance level. The optimum ranges of recipe on organoleptic properties of pumpkin pouch drink were estimated on 86.5～87.5％ of the old pumpkin extract, 0.36～0.42％ of xanthan gum and 9％ of vinegar.

• Journal of the Korea Concrete Institute
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• v.23 no.4
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• pp.487-494
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• 2011

In this research, the possibility of using bottom ash as a binder for the alkali-activated cement mortar is studied. Several experiments were performed to investigate the variation of the material properties according to the mix proportion. In the experimental program, the flowability and compressive strength were evaluated for various values of water/ash ratio, activator/ash ratio, sodium silicate to sodium hydroxide ratio, curing temperature, and the fineness of bottom ash as the main variables. The experimental results showed that high strength of 40 MPa or greater could be achieved in $60^{\circ}C$ high temperature curing condition with proper flowability. For $20^{\circ}C$ ambient temperature curing, the 28 days compressive strength of approximately 30MPa could be obtained although the early-age strength development was very slow. Based on the results, the range of optimized mix design of bottom-ash based alkali-activated cement mortar was suggested. In addition, using the artificial neural network analysis, the flowability and compressive strength were predicted with the difference in the mix proportion of the bottom-ash based alkali-activated cement mortar.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.5
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• pp.92-103
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• 2015

Box-Wilson experimental design method, known as central composite design, is the design of any information-gathering exercises where variation is present. This method was devised to gather as much data as possible in spite of the low design cost. This method was employed to model the effect of mixing factors on several performances of 60 MPa high strength self compacting concrete and to numerically calculate the optimal mix proportion. The nonlinear relations between factors and responses of HSSCC were approximated in the form of second order polynomial equation. In order to characterize five performances like compressive strength, passing ability, segregation resistance, manufacturing cost and density depending on five factors like water-binder ratio, cement content, fine aggregate percentage, fly ash content and superplasticizer content, the experiments were made at the total 52 experimental points composed of 32 factorial points, 10 axial points and 10 center points. The study results showed that Box-Wilson experimental design was really effective in designing the experiments and analyzing the relation between factor and response.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4832-4836
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• 2012

In general, there are needed lots of time and experiments for determination of optimum asphalt content and mix design. The experimental results are highly depended on the skill of testers. Bailey suggested the proper aggregate gradation of hot mix asphalt are a function of special size and passing percent of the specified aggregate to reduce the test errors. In this paper, the asphalt mix designs of 19mm dense graded mix and PA-20mm for FHWA were carried out, using Bailey's method. The use of Bailey method can cut down the testing times to get the proper aggregate gradation for asphalt mix design. In case of 19mm dense graded asphalt mixture, the measured values of CA, $FA_c$, $FA_f$ are 0.724, 0.440, and 0.455, which are within the suggested values by Bailey. Also, in case of PA-20 graded asphalt mixture, the measured values of CA, $FA_c$, $FA_f$ are 0.646, 0.476, and 0.450, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.1
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• pp.69-74
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• 2002

In the present study, we investigated the quality characteristic of ginseng cultured in bioreactor system and the optimum recipe condition of the liquid tea using cultured ginseng. The contents of soluble solid and crude saponin in cultured ginseng were 31.8% and 1.94%, respectively, which were lower than commercial ginseng. In the concentrated extract, crude saponin content was 4.77% and the contents of ginsenoside Rc, Re and Rg$_1$were 7.36, 4.40 and 1.75 mg/g, respectively. The ginsenoside Rb$_1$and Rb$_2$, main contents of commercial ginseng, were not detected. The optimum ranges of recipe on organoleptic properties of ginseng liquid tea were estimated on 9.0~10.4% of the extract, 6.8~8.1% of apple vinegar and 40% of fructose. The liquid tea using commercial ginseng showed higher scores of sensory lest than the liquid tea using cultured ginseng in bioreactor system at the given condition, 10% of the extract, 7% ofapple vinegar and 40% of fructose, with the same recipe condition ranges.

• Journal of the Korean Geotechnical Society
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• v.27 no.5
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• pp.5-15
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• 2011

Recent increase of large scale construction near costal area has also increased the application of soft ground treatment. As a result, solidification with cement and lime which increases stability and durability of soils, is frequently used for surface layer stabilization in soft ground site. While stabilization of very soft clay with high plasticity and compressibility has widely been studied, studies on silty clay with low plasticity and compressibility are relatively rare. In this study, after stabilizing low plasticity silty clay of Songdo area with cement and lime under various water contents, mixing ratio, and curing time, uniaxial compression test and plate load test were performed. Strength properties from both tests were considerably consistent. And trackability of construction equipment on the treated surface layer of dredged land was estimated. Finally, optimum mixing condition for Songdo silty clay was proposed.

• 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.