• Journal of the Korean Recycled Construction Resources Institute
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• 제2권1호
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• pp.128-135
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• 2006

Steel slag (divided into electric arc furnace slag and convener slag) is being produced by millions of tons per every year in many industrial countries. About 6.5 million tonnes of steel slag is produced yearly as an industrial by-product in Korea. Generally natural aggregate is relatively stable and does not enter into complex chemical reactions with water. Unfortunately, however. steel slag aggregate contains a small amount of free lime. The hydration of free lime makes steel slag aggregate unstable and liable to expand. In this paper, firstly, several aging methods are used in order to decrease the volume expansion of electric arc furnace slag, that is stabilization. The volume expansion of electric arc furnace slag is formulated from the experiment. From the formula, the residual expansibility is predicted with immersion expansion. Compressive strength of concrete with electric arc furnace slag has relation with the residual expansibility in slag aggregate.

• Journal of the Korea Concrete Institute
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• 제25권2호
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• pp.195-200
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• 2013

New thermal crack control system for mass concrete was developed to increase quality and to save construction period and cost. The principle of this system is that the curing water having proper temperature is supplied automatically to the surface of mass concrete member to keep the temperature difference between center and surface of concrete less than generally recommended temperature difference ($20^{\circ}C$). Mock-up test was conducted to investigate the validity of newly developed curing system. As a result, no crack was founded in the specimen using automated curing system developed in this study, while many cracks occurred in another specimen without automated curing system. It was also confirmed that the strength and the durability of the concrete cured by automated curing system were improved.

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.445-448
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• 2008

It is essential that concrete component is made up with aggregate, cement and water. But today, Public concern is increasing of a variety structure and ocean environmental, resource recycle. Also, According to heat of hydration rising, Concrete is make a causative of concrete-crack. Concrete-crack cause a falling-off in quality of concrete. consequently, High-performance concrete is evaluated by concrete material properties and carbonation resistance with different admixture(fixing fly-ash 20%), granulated blast furnace slag replacement ratio (30%, 45%) different W/B (26%, 30%, 34%) and XRD(X-ray Diffraction) analysis.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• 제22권1호
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• pp.120-132
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• 2009

Objective : Yukmijihwang-tang is one of the important medicines for blood- deficiency and yin-deficiency. Atopic dermatitis usually shows dampness-heat pattern in its acute stage and blood-deficiency or yin-deficiency pattern in its chronic stage. Therefore, I hypothesized that Yukmijihwang-tang is effective on atopic dermatitis and investigated the effects of Yukmijihwang-tang on NC/Nga mice's atopic dermatitis induced by DNCB. Methods : The NC/Nga mice with atopic dermatitis were divided into four groups: three experimental groups and one control group. The experimental groups were respectively put on 2.5g(YM-2.5), 5g(YM-5) and 10g(YM-10) of Yukmijihwang-tang extract per their weight once a day for 10 days while the control group was fed normal saline. After 10 days, I measured TEWL(transepidermal water loss), observed scratching behaviors, conducted a skin biopsy and checked levels of Total IgE, IL-4 and $IFN-\gamma$ on NC/Nga mice. Results : 1. Yukmijihwang-tang significantly suppressed skin dryness. In particular, YM-5 and YM-10 had better skin hydration than YM-2.5. 2. Yukmijihwang-tang significantly suppressed pruritus while there was no significant difference among the experimental groups. 3. Yukmijihwang-tang retained skin structure(epidermis, dermis and subcutaneous fat). 4. Yukmijihwang-tang reduced Total IgE level while there was no significant difference between the control group and the experimental groups. 5. Yukmijihwang-tang did not reduce IL-4(Th2 cytokine) level. 6. Yukmijihwang-tang significantly reduced $IFN-\gamma$(Th1 cytokine) level. In particular, YM-2.5 and YM-5 had lower $IFN-\gamma$ level than YM-10. Conclusion : The results suggest that Yukmijihwang-tang suppresses skin dryness and pruritus, retains skin structure and is effective on chronic atopic dermatitis which is associated with Th1 cytokines in the immune response.

• Journal of the Korean Recycled Construction Resources Institute
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• 제4권3호
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• pp.62-68
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• 2009

This research examined engineering properties of high performance concrete, when substitution rate of BS increases. A summary of the test result is as follows. The fluidity of unset concrete increases as the substitution rate of BS increases. The amount of air is reduced more or less, but it seems that enough amount of air can be secured by using more air-entraining agent. Setting time is dramatically delayed as the substitution rate of BS increases. The compressive strength of hardening concrete was weaker than OPC before 28 days passes, due to latent hydraulic property of BS. However, after 28 days, it shows same or better property, which is exceptional for the practical uses of hyper strength concrete. Changes in drying shrinkage rate is quite much, because when hydration happens, the amount of free water in concrete increased as W/B gets larger. The amount of drying shrinkage increases as BS substitution rate increases, but every composition shows less than $-500{\times}10^{-6}$, which is relatively fine.

• Journal of the Korea Institute of Building Construction
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• 제17권3호
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• pp.269-277
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• 2017

In this work, as a preliminary experimental works, which focuses on utilizing separated pastes from activated (or radioactive) concrete as solidifying agents for radioactive waste immobilization, were performed. It was found that density of hydrated cement paste, which was lower than that of ordinary portland cement, increased as temperature for heat treatment increased. Highest compressive strength was observed with the specimens that was heat treated at $600^{\circ}C$. However, heat treatment over $700^{\circ}C$ showed higher CaO content that caused higher heat of hydration after in contact with water, lows of workability, and lower strength. Based on experimental results, it is suggested that $600^{\circ}C$ heat treatment is more appropriate for waste cement paste to be used as a solidifying agent.

• Journal of the Korean GEO-environmental Society
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• 제2권1호
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• pp.91-101
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• 2001

This paper investigates the effectiveness of quick lime piles for soft ground improvement. The field tests based on the results of the laboratory test were performed, and the results of field tests were compared with those of numerical analyses(FEM). The results of the field test showed that the domestic quick lime was very effective in reducing the water contents of the surrounding ground quickly due to its characteristics such as digestion, absorption, and exothermic reactions. Accordingly, consolidation occurred without any additional load increment and the shear strength of surrounding ground was increased more than twice. Therefore the quick lime pile method could be considered as an excellent improvement technique reducing the improvement period for soft ground. For the practical applications of the quick lime pile method, issues such as hydration heat, particulation and equipment enhancement should be solved through continuous research and development.

• Journal of the Korean Ceramic Society
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• 제24권1호
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• pp.77-85
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• 1987

Hardened cement paste is mainly affected by corrosion of sulphate and chlorine ions in sea water. In this investigation, many specimens were made with the cement clinker minerals such as C3S, C3A, C4AF and their mixture according to cement composition added various blending materials. After the specimens were immersed in 4% MgSO4 and MgCl2 solutions, the product of reaction, the microstructure of specimen and Ca+2 ion leached in the solution were studied. The formation of Ca(OH)2 in the specimen of C3S is reduced relatively by adding pozzolanic admixtures. The chlorine ion is easily diffuse into the C3S specimen and produced CaCl2 compound, and it makes the specimen porous by leaching out itself into the solution. The specimen of C3A, C4AF are broken down by expanding reaction of ettringite and gypsum compound produced in the MgSO4 solution. At a later period, the ettringite is transformed into gypsum and 5MgO.2Al2O3·15H2O. The C3A in the MgCl2 solution combines chlorine ion to form Friedel's salt and prevents the diffusion reaction of chlorine ion into the specimen. Granulated slag shows inferior effect on the resistance of the specimen in MgSO4 solution by forming ettringite and gypsum, but good result in MgCl2 solution. Pozzolanic materials, on the whole, offer noticable effect on the resistance of the specimen in both solutions.

• Journal of the Korea Institute of Building Construction
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• 제4권1호
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• pp.127-132
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• 2004

CFT(Concrete Filled Steel Tube) is a structure of circular or squared of steel column filled with concrete. The steel tube holds the concrete inside and that makes this structure to perform superior features on stiffness, proof stress, transformation, fire resistance and construction itself. In this study, by over the 800kgf/$\textrm{cm}^2$ of high strength concrete for CFT column, research has been done on the basic property of matter such as fluidity, resistance on segregation, compressive strength, setting icons of the concrete filled in the steel tube under conditions of standard weather. Physical properties of concrete for CFT that Concrete with silica fume, fly ash of air entraining and high-range water reducing agent, that used to CFT column research purpose to find the most ideal composition, which is achieved by the investigation in the concrete's property of matter like ability of Slump, Slump Flow, Air content, Bleeding, and Settlement. For this study, experiments which are bused on obtained the result through physical test are practiced, with all of the experiment, specimens only for control are produced in each method of curing and analyzed to relations with core strength in mock-up test. In mock-up test, the research is studied compactability of concrete filled in tube and degree of hydration hysteresis, as a basic reference for applying to field of CFT column which is used over 800kgf/$\textrm{cm}^2$ high strength concrete.

• KOREAN JOURNAL OF CROP SCIENCE
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• 제34권2호
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• pp.155-162
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• 1989

This experiment was conducted to investigate the endosperm characteristics of an opaque rice which was derived from an Indica cultivar Pokhareli Mashino. Grain apperance of opaque rice looked similar to the waxy grain, while the blue-color response to the iodine solution was similar to non-waxy endosperm. The shape of starch granules was alike each other, but their size were different each other with the smallest of the opaque rice. Their cristaline structure of starch granules were A type. The content of total protein and most of the amino-acids of opaque rice was about 1.5 times of other varieties. Alkali digestibility of the opaque rice was very low. Total water uptake and hydration rate of opaque rice was similar to non-waxy variety Tongil. Amylogram characteristics such as viscosity, setback and consistency of opaque rice revealed medium value between. waxy and non-waxy rice.