• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.2
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• pp.166-173
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• 2019

In this paper, the reaction properties of silica source in the accelerated curing conditions using autoclave and the fundamental properties of inorganic Micro Defect Free(MiDF) concrete using silica source are studied. Studies show that Si ions elution rate from silica source in autoclave curing is higher in amorphous source. In tap water conditions, solids which is source after autoclaved curing show a higher mass reduction in amorphous materials, which is attributed to the higher elution rate of ion. In $Ca(OH)_2$ solution conditions, amorphous materials show higher mass increase, due to increase in C-S-H minerals. From experiment for influence on the properties of MiDF concrete by using nano silica materials, the specimen with silica fume shows an increase in compressive strength and a decrease in absorption depending on replacement rate up to 5.5%, while nano silica with amorphous phase and high-fineness shows a decrease in compressive strength and decrease in the water absorption. The specimen with nano silica increases the pore below 10,000nm, but reduces pore between 10,000 and 100,000nm. The above results show that the porosity and absorption rate of MiDF concrete can be reduced by using amorphous nano-size silica. However, to reduce the pore of 50 to 10,000nm, better dispersion of nano material in the cement matrix will be necessary. We will focus on the this item in the next research.

• Journal of Life Science
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• v.32 no.3
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• pp.232-240
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• 2022

Various methods are known for preparing liposomes, the simplest being the Bangham method which has been widely used. Although it is possible to produce liposomes effectively on a small experimental level with this approach, large-scale production cannot be easily performed due to difficulties in removing the organic solvent and the size of the reactor required to form the lipid film. On the other hand, emulsion can mass produce tons of liposomes with uniform particles but has the disadvantage of a significantly low capture rate. This study therefore developed an optimal liposome processing method using heat with improved capture rate and stability, and bio-absorption experiments were performed by oral administration to SD rat alongside capture rate, particle size, and zeta potential. Through the heating method, a small and uniform liposome of about 214 nm was formed and the capture rate was 38.67%, confirming that the liposome prepared by heating has a higher capture rate than the 26.46% achieved through emulsion. Comparing blood concentrations, it showed a 1.5 to 2 fold increase in all groups, gradually decreasing until 4-12 hr. The highest blood concentration of ascorbic acid powder was about 12.017 ㎍/ml, the emulsion liposome 13.871 ㎍/ml, and the heating liposome 16.322 ㎍/ml, thereby showing an improved absorption rate.

• Economic and Environmental Geology
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• v.53 no.1
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• pp.87-98
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• 2020

The bird track fossil site in Haman Formation is divided into seven sedimental layers by the sedimentary structures, lithofacies and sequences. The bird tracks top on the highest layer, which includes ripple marks and suncracks. The layer has lithofacies with reddish grey siltstone and dark grey mudstone, alternately. As an analysis for the same rocks of the fossil site, physical properties show on mean values for 0.62% of absorption rate, 1.64% of porosity and 2.63 of specific gravity. Rock-forming minerals composed mainly of plagioclase, quartz, calcite, chlorite and mica. Meanwhile, we executed an experiments based on the petrography and weatherings to find a proper consolidants. In the experiments, the OH 100 reagent proved stable aspect and the lowest transition rate in terms of weight and chromaticity. Also, it showed the highest increase in ultrasonic velocity, improving the physical properties of the rocks. In the case of applying the OH 100 with antihygro, an swelling inhibitors on the sedimentary rocks, the chromaticity indicated an stable transition aspect. When it comes to the physical properties, the antihygro also decreases the porosity effectively. Thus, the most proper method for the fossil site of Haman Formation is to apply antihygro and OH 100 reagents since the rocks includes clay minerals that show swelling characteristics. However, this result is deduced from an indoor application experiments, leaving the necessity of verification how these reagents would affect the bird tracks site under the field condition.

• International Journal of Highway Engineering
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• v.11 no.3
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• pp.23-32
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• 2009

In this paper an experimental program was launched to determine the mechanical and durability properties of spall repair materials (RCC: 3 items, PCC: 2 items, PC: 3 items). Test items were mechanical property tests such as setting times, strengths, modulus of elasticity, plastic shrinkage, and durability tests such as dynamic modulus ratio, bond property with freeze-thaw, water absorption, chemical resistance, ultraviolet exposure. Modulus of the PC products exhibits ductile while the modulus is in the order of RCC > PCC > PC. At early ages the PC products experience higher plastic shrinkage than others, henceforth stable at 28 days. Other test results such as dynamic modulus ratio, absorption, and chemical resistance show that the PCs are superior to the PCCs and the RCCs. Except for PC-2, all patch materials had bond strength more than 1.3MPa after freeze-thaw cycles of 200~300 while the PCs and the PCCs seem to be better than the RCCs. With 500 hours of ultraviolet exposure, all patch materials showed to have no crack or deterioration at the surface.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.04a
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• pp.377-382
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• 2010

건물의 대형화 고층화로 고강도 콘크리트의 사용이 증대되면서 고강도 콘크리트의 화재 시 폭열 대책이 필요하다. 본 연구는 전국 화력발전소에서 매립되는 Bottom Ash와 EPS를 재활용하여 건축소재의 내화기준에 만족하고 자원순환 소재의 새로운 개발방향을 제시하고자 난연성이 가미된 경량콘크리트 패널을 개발하여 그 난연 성능 및 벽체로서의 성능을 실험하였다. 실험은 Bottom Ash를 활용한 코팅 경량골재를 2개 Type으로 개발하여 단위중량, Flow, 압축강도, 열전도율, 부착강도, 건조수축, 흡수율, 난연 성능을 평가하였다. 그 결과 대부분의 데이터가 KS기준에 맞게 나왔으며, 난연 성능 또한 1급으로 나왔다. 이로서 폐자재인 Bottom Ash와 EPS를 재활용하여 화재 시 난연성능이 확보됨은 물론 국가성장핵심 사업인 녹색성장에 걸맞은 새로운 경량콘크리트 패널을 개발할 수 있게 되었다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.1
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• pp.121-128
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• 2004

This study aims to attain the basic data needed for the adaptation and application of polymer cement concrete as a new construction material by reviewing the various physical characteristics of polymer cement concrete following the changes in polymer type. The research found that cement concrete mixed with polymer, while it had some variation, had excellent qualities in all of compressive strength, tensile strength, water absorption, weight reducing ratio, and resistance of freezing and thawing.

• Journal of the Korea Concrete Institute
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• v.23 no.3
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• pp.311-320
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• 2011

Fly ash (FA), byproduct from power plant has been actively used as mineral admixture for concrete. However, since bottom ash (BA) is usually used for land reclaim or subbase material, more active reuse plan is needed. Pond ash (PA) obtained from reclaimed land is mixed with both FA and BA. In this study, 6 PA from different domestic power plant are prepared and 5 different replacement ratios (10%, 20%, 30%, 50%, and 70%) for fine aggregate substitutes are considered to evaluate engineering properties of PA as fine aggregate and durability performance of PA concrete. Tests for fine aggregate of PA for fineness modulus, density and absorption, soundness, chloride and toxicity content, and alkali aggregate reaction are performed. For PA concrete, durability tests for compressive strength, drying shrinkage, chloride penetration/diffusion, accelerated carbonation, and freezing/thawing are performed. Also, basic tests for fresh concrete like slump and air content are performed. Although PA has lower density and higher absorption, its potential as a replacement material for fine aggregate is promising. PA concrete shows a reasonable durability performance with higher strength with higher replacement ratio. Finally, best PA among 6 samples is selected through quantitative classification, and limitation of PA concrete application is understood based on the test results. Various tests for engineering properties of PA and PA concrete are discussed in this paper to evaluate its application to concrete structure.

• Magazine of the Korean Society of Agricultural Engineers
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• v.11 no.1
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• pp.1604-1615
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• 1969

This experiment was carried out as one of the basic studies to improve the acid resistance of concrete and it was conducted to investigate some relations among physical properties such as basorption, ratio of water to cement, compressive strength, density and ratio of mix to weight losses of mortar when exposed to 0.1 N solution of hydrochrolic acid. The results obtained from the limited data secured so far in this experiment are summarized as follows: 1. The specimens used in the experiment were made of 5 cubic centimeters of mortar having such various ratios of mix by weight as 1 : 1, 1 : 3, 1 : 5, 1 : 7, 1 : 10. 2. Physical tests included compressive strengths at 7 days, 28 days, 3 months, and 6 month, and 5 hour boiling absorption test. 3. In acid test, every specimen was immersed into 0.1 N solution of hydrochrolic acid. The specimens exposed to the acid solution were weighed to determine the weight losses of the acid-corroded at one week interval for 7 weeks exposure, and the old acid solutions were also changed to fresh one when weighed the weight losses by acid attack at one week interval. 4. The correlative relations were found among physical properties and they are expressed by certain formulas as follows; i) Relation between ratio of mix and absorption Y = 1.036x + 13.53 where Y: absorption(%) X: ratio of mix ii) Relation between ratio of mix and ratio of water-cement Y = 0.204x + 0.214 where Y: ratio of water-cement. X: ratio of mix iii) Relation between ratio of water-cement and absorption Y = 5.01x + 12.53 where Y: absorption(%). X: ratio of water-cement iv) Relation between density and absorption Y = 50.6 - 0.0176X where Y: absorption(%). X: density($kg/m^3$) v) Relation between density and ratio of water cement Y = 7.2183 - 0.0033X where Y: ratio of water-cement . X: density($kg/m^3$) 5. After completing the acid exposure test the specimens were corroded and , the per cent ranges of weight losses varies from a minimum of 20.4 per cent at a 1 : 1 mix to a maximum of 92.0 per cent at a 1:10 mix 6. The correlative relations of physical properties of mortar to weight losses by acid attak were found and they are also expressed by certain formulas as follows: i) Relation between weight losses and ratio of mix Y = 8.59X + 8.63 where Y: weight losses(%), X: ratio of mix ii) Relation between wieght losses and absorption Y = 0.121x + 12.43 where Y: absorption(%). X: weight losses(%) iii) Relation between weight losses and ratio of w/c Y = 0.0226X + 0.07 where Y: ratio of w/c X: weight losses(%) iv) Relation between weight losses and compressive strength LogY = 3.6097 - 0.05058X + 0.00022$X^2$ where Y: compressive strength ($kg/cm^3$) X: weight losses(%) v) Relation between weight losses and density Y = 2153.1 - 6.62X where Y: density($kg/m^3$) X: weigh losses(%) 7. In order to make better acid resistant mortar, it could be concluded that a 1 : 3 mix or richer mixes, adequate mixing water to minnimize the ratio of water-cement considering the workability, 16 per cent or less absorption by 5 hour boiling water, 1,800 kilogram per cubic meter or denser density by absolute weight base and 200 kilogram per square meter or compressive strength at 20 day, etc are required so as to obtain acid-resistant mortar. In addition to the above, it might be recommonded to select the fine aggregate and to use better equipments such as a mechanical vibrator, a mechanical mixer etc. in concrete manufacturing works.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.247-248
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• 2010

This study is of manufacturing artificial lightweight aggregates using industrial wastes. The ingredients for manufacturing lightweight aggregate were stone sludge and bottom ash for main materials, and steel slag(SS), glass abrasive sludge(GS) and blast furnace slag(BS) respectively for accessory material. Their precursors were sintered in the range of $1,050{\sim}1,150^{\circ}C$ for 5 min. The sintered results show that the lightweight aggregate with SS had low water absorption ratio and density at $1,150^{\circ}C$. There's a possibility that if GS is used more than the range of this study, GS can be manufactured lightweight aggregate. But it is judged that BS are incongruent to be used for a raw material of lightweight aggregate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.4
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• pp.459-464
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• 2008

This study was performed to investigate the effect of calcium-rich large anchovy on calcium metabolism in rats for 5 weeks. Experimental animals were randomly assigned to 5 treatments with 14 heads of Spraque Dawley male rats in each group. The experimental diets were as follows; market milk group (M) as control, market milk+calcium-rich large anchovy group (MA), market milk＋calcium carbonate group (MC), market milk+calcium lactate group (ML), and enriched-calcium market milk group (M2), which were formulated with commercially semi-purified rat chow (AIN-diet) to maintain the same level of calcium (1%) in all groups. Femur lengths of M and M2 groups were significantly higher than other groups. Bone mineral density (BMD) and bone mineral content (BMC) and calcium content of femur were the highest in MA group than other groups. In vitro and in vivo calcium absorption rates were high in MA group (7.30% vs 27.50%) compared with those of the other groups. Serum total-cholesterol and HDL-cholesterol levels were significantly different between M group and MA group (p<0.05). Creatinine levels were significantly higher in M, MA and MC groups than in M2 group (p<0.05). Serum calcium, osteocalcin and ALPase activities were higher in calcium-rich large anchovy (MA) group among the treatments, but there was no significant difference. SGOT activity was significantly lower in M2 group than those of M, MA and MC groups (p<0.05). These results may indicate that the calcium-rich large anchovy has enforced the BMD, BMC and calcium absorption rates of in vitro and in vivo compared with the other groups and might be a calcium-enriched food with large anchovy.