• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.937-940
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• 2008

Recently, the recycling and reusing of construction and demolition waste concrete is urgently required because generation quantity of construction and demolition waste concrete is greatly increased according to the rapid increasing of urban redevelopment project. On the other hand, the problem solution for demand and supply unbalance of fine aggregate is urgently required because of the restriction of collecting sea fine aggregate by intensification of environment influence evaluation and the shortage of river fine aggregate. but a quality of aggregate as building structure is not demonstrated. Therefore it is the objective of this study to estimate plastic and early dry shrink crack of fiber reinforced concrete using a recycled aggregate by plat-ring test and mock-up test of exposure to the air. as a result, in case of plat- ring test, developing crack is wider using recycled aggregate concrete than natural aggregate concrete, is wider using fiber reinforced concrete than non fiber. in case of mock-up test of exposure to the air, it is similar to plat-ring test.

• Journal of the Korean Wood Science and Technology
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• v.25 no.4
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• pp.99-107
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• 1997

This study was executed to test the possibility of replacement for domestic Japanese larch(Larix leptolepis) for hardwoods and to acquire the information about the effects of drying temperature on internal temperature, moisture content and drying defects. In high-temperature drying, internal temperature increased rapidly to boiling point, immediately after that point the internal temperature rising rate was reduced. In the case of drying at temperature of $125^{\circ}C$, internal temperature could reach at boiling point in a very short time. Moisture content in high-temperature drying showed constant drying rate period and first period of falling rate drying together in 4 hours since experiment begun. There was no strong correlation between initial moisture content and final moisture content. Average drying rate at $115^{\circ}C$, $120^{\circ}C$ and $125^{\circ}C$ was 1.42%/hr, 1.88%/hr and 2.02%/hr, respectively; the case of drying temperature of $125^{\circ}C$ showed most rapid drying rate. Drying rate of $125^{\circ}C$ was so rapid that it showed more severe shrinkage, bow, collapse, end check, and internal check development than in other drying conditions. The result of this study showed the strong possibility of high-temperature drying for Japanese larch, and to dry Japanese larch optimally, dry bulb temperature should not exceed $120^{\circ}C$.

• Horticultural Science & Technology
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• v.19 no.2
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• pp.179-185
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• 2001

Throughout the world, physical and chemical analyses of horticultural substrates are carried out in many different ways at the different laboratories. In Europe, standardization in properties and analytical methods of horticultural substrates has been a topic over the last decades. As a result, the CEN methods as European standard methods for the physical and chemical analyses were introduced and the final draft was reported in 1999 by CEN(Committee for European Standardization). Dry matter and moisture content are analyzed after drying samples at $103^{\circ}C$. Laboratory compacted bulk density is analyzed by determining the weight of sample compacted in the test cylinder with constant volume. Dry bulk density, particle density, total pore space, water volume, air volume and volume shrinkage are determined by saturating, draining and drying the sample using double rings and a sand suction table. pH and EC are analyzed by 1:5(sample:distilled water) extraction method on the basis of volume. Organic matter and ash content are determined after drying and combusting the samples. Now, CEN methods are being regarded almost as European standard methods. Further study needs to be carried out for universal applicability of the CEN methods to all the substrates.

• Journal of the Korean Wood Science and Technology
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• v.10 no.3
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• pp.13-44
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• 1982

1. Since long time ago, it has been talked about that soaking wood into water for a long time would be profitable for the decreasing of defects such as checking, cupping and bow due to the undue-shrinking and swelling. There are, however, no any actual data providing this fact definitly, although there are some guesses that water soluble extractives might effect on this problem. On the other hand, this is a few work which has been done about the effect of water soluble extractives upon the some physical properties of wood and that it might be related to the above mentioned problem. If man does account for that whether soaking wood into water for a long time would be profitable for the decreasing of defects due to the undue-shrinking and swelling in comparison with unsoaking wood or not, it may bring a great contribution on the reasonable uses of wood. To account for the effect of water soluble extractives upon physical properties of wood, this study has been made at the wood technology laboratory, School of Forestry, Yale university, under competent guidance of Dr. F. F. Wangaard, with the following three different species which had been provided at the same laboratory. 1. Pinus strobus 2. Quercus borealis 3. Hymenaea courbaril 2. The physical properties investigated in this study are as follows. a. Equilibrium moisture content at different relative humidity conditions. b. Shrinkage value from gre condition to different relative humidity conditions and oven dry condition. c. Swelling value from oven dry condition to different relative humidity conditions. d. Specific gravity 3. In order to investigate the effect of water soluble extractives upon physical properties of wood, the experiment has been carried out with two differently treated specimens, that is, one has been treated into water and the other into sugar solution, and with controlled specimens. 4. The quantity of water soluble extractives of each species and the group of chemical compounds in the extracted liquid from each species have shown in Table 36. Between species, there is some difference in quantity of extractives and group of chemical compounds. 5. In the case of equilibrium moisture contents at different relative humidity condition, (a) Except the desorption case at 80% R. H. C. (Relative Humidity Condition), there is a definite line between untreated specimens and treated specimens that is, untreated specimens hold water more than treated specimens at the same R.H.C. (b) The specimens treated into sugar solution have shown almost the same tendency in results compared with the untreated specimens. (c) Between species, there is no any definite relation in equilibrium moisture content each other, however E. M. C. in heartwood of pine is lesser than in sapwood. This might cause from the difference of wood anatomical structure. 6. In the case of shrinkage, (a) The shrinkage value of the treated specimen into water is more than that of the untreated specimens, except anyone case of heartwood of pine at 80% R. H. C. (b) The shrinkage value of treated specimens in the sugar solution is less than that of the others and has almost the same tendency to the untreated specimens. It would mean that the penetration of some sugar into the wood can decrease the shrinkage value of wood. (c) Between species, the shrinkage value of heartwood of pine is less than sapwood of the same, shrinkage value of oak is the largest, Hymenaea is lesser than oak and more than pine. (d) Directional difference of shrinkage value through all species can also see as other all kind of species previously tested. (e) There is a definite relation in between the difference of shrinkage value of treated and untreated specimens and amount of extractives, that is, increasing extractives gives increasing the difference of shrinkage value between treated and untreated specimens. 7. In the case of swelling, (a) The swelling value of treated specimens is greater than that of the untreated specimens through all cases. (b) In comparison with the tangential direction and radial direction, the swelling value of tangential direction is larger than that of radial direction in the same species. (c) Between species, the largest one in swelling values is oak and the smallest pine heartwood, there are also a tendency that species which shrink more swell also more and, on the contrary, species which shrink lesser swell also lesser than the others. 8. In the case of specific gravity, (a) The specific gravity of the treated specimens is larger than that of untreated specimens. This reversed value between treated and untreated specimens has been resulted from the volume of specimen of oven dry condition. (b) Between species, there are differences, that is, the specific gravity of Hymenaea is the largest one and the sapwood of pine is the smallest. 9. Through this investigation, it has been concluded that soaking wood into plain water before use without any special consideration may bring more hastful results than unsoaking for use of wood. However soaking wood into the some specially provided solutions such as salt water or inorganic matter may be dissolved in it, can be profitable for the decreasing shrinkage and swelling, checking, shaking and bow etc. if soaking wood into plain water might bring the decreasing defects, it might come from even shrinking and swelling through all dimension.

• Journal of the Korea Furniture Society
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• v.21 no.1
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• pp.62-71
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• 2010

This study was carried out to investigate the physical and mechanical properties of 6 hardwoods before and after heat treatment in an effort to produce the high quality industrial lumber product. The object of the research was to design living products with heat treated woods. The results were as follows. Specific gravities of green woods were in range from 0.87 to 1.12. The specific gravities of never treated woods showed higher than those of the heat treated woods. The shrinkage of heat treated woods when green to air & oven dry was significantly low, compared to never treated woods. The compression strengths parallel to grain of heat treated woods showed higher than those of never treated woods. The moduli of rupture (MOR) of never treated and heat treated woods were $170.37N/mm^2~107.07N/mm^2$ and $122.78N/mm^2~61.27N/mm^2$ respectively. MORs of heat treated woods showed lower than those of never treated woods. The modulus of elasticity (MOE) of heat treated woods showed higher than those of never treated woods.

• Journal of the Korea Furniture Society
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• v.18 no.1
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• pp.39-46
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• 2007

This study was carried out to investigate the wood properties for efficient utilization of warm temperate tree species of Quercus acuta Thunb. grown in Korea. Fundamental wood properties in the anatomical, physical, mechanical and chemical characteristics were examined. Quercus acuta Thunb. is a radial-porous, straight grained and fine textured wood. The heartwood is not clearly distinguished from the sapwood. In physical properties, it has a high oven-dry specific gravity of $0.85{\pm}0.02$, and high shrinkage from green to air-dried condition of $7.05{\pm}0.52%$ in radial and $11.13{\pm}0.48%$ in tangential direction. Mechanical properties determined are strong with the MOR of $1,065{\pm}90kgf/cm^2$, and tensile strength parallel to grain of $1,490{\pm}258kgf/cm^2$ and shear strength of $175{\pm}13kgf/cm^2$. Also, this wood has high extractive contents: 11.11% for cold and 13.51% for hot water.

• Geomechanics and Engineering
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• v.15 no.2
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• pp.729-738
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• 2018

Soft clay soils due to their various geotechnical problems, stabilized with different additives. Traditional additives such as cement and lime will not able to increase the soil strength properties significantly. So, it seems necessary to use new additives for increasing strength parameters of soft clay soils significantly. Among the new additives, epoxy resins have excellent physical and mechanical properties, low shrinkage, excellent resistance to chemicals and corrosive materials, etc. So, in this research, epoxy resin used for stabilization of soft clay soils. For comprehensive study, three clay soil samples with different PI and various clay mineral types were studied. A series of uniaxial tests, SEM and XRD analysis conducted on the samples. The results show that using epoxy resin increases the strength parameters such as UCS, elastic modulus and material toughness about 100 to 500 times which the increase was dependent on the type of clay minerals type in the soil. Also, In addition to water conservation, the best efficiency in the weakest and most sensitive soils is the prominent results of stabilization by epoxy resin which can be used in different climatic zones, especially in hot and dry and equatorial climate which will be faced with water scarcity.

• Geomechanics and Engineering
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• v.12 no.1
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• pp.111-125
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• 2017

Swelling and shrinkage characteristics of expansive fine grained soil cause volumetric changes followed by distress and damage to the structures. Soil stabilization can be explained as the alteration of the soil properties by chemical, mechanical or any other means in order to enhance the engineering properties of the soil. Utilization of industrial wastes in soil stabilization is cost effective and environment friendly. This paper presents an experimental study on stabilization of expansive soil using industrial wastes, viz. fly ash and dolochar. The paper includes the evaluation of engineering properties like unconfined compressive strength and California bearing ratio (CBR) of expansive soil collected from Balasore district of Odisha stabilized with fly ash and dolochar in different proportions and to predict the influence of these additives on engineering properties and strength characteristics of expansive soil. Both fly ash and dolochar were found to increase the CBR and decrease many index properties such as liquid limit, plastic limit, plasticity index, swelling index and UCS, thus enhancing the strength parameters of expansive soil.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.6
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• pp.1283-1287
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• 1999

This study was carried out to develop new processed food from cherry tomatoes. The dried cherry tomatoes were prepared by using a sequence of osmotic dehydration, air drying, vacuum drying and freeze drying. The moisture contents of dried cherry tomato products by nontreatment and osmosis treatment were about 11~13% and 7.5~ 10%, respectively. The vitamin C contents of the dried product after osmotic dehydration were higher than those of the dried products by nontreatment. The vitamin C content of the freezing dried product was the highest of the others. The vacuum dried product by nontreatment was retained color of fresh fruit in the change of color. The ΔE value of the air dried product was lower than those of the others. As a result to microscopic analysis, fresh cherry tomato was observed regular tissue, while cherry tomato treated by osmosis was observed a cell collapse following the loss of water. The dried product had cell shrinkage and dense tissue. And the cell wall of dried products after osmotic dehydration were much more damage than those of nontreatment dried product. The palatability of the air dried product was the best of three drying methods. The dried cherry tomatoes treated by osmosis were superior to the dried cherry tomatoes by nontreatment.

• Fashion & Textile Research Journal
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• v.18 no.6
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• pp.878-888
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• 2016

In this study, wool/nylon(50/50%) blend yarn and its fabrics for tra-biz(complex word of travel+business) garment were prepared, and its wear comfort characteristics were investigated through thermal manikin and human-body wearing experiment. In addition, tactile wearing performance from fabric mechanical properties and the dimensional stability and the pilling of the fabric specimen during wearing and dry-cleaning were measured and compared with those of wool 100% fabric specimen. Heat keepability of the wool/nylon(50/50%) blend fabric by thermal manikin experiment was superior than that of wool 100% fabric, this result was verified with human-body wearing experiment and its result coincided well with this experimental result. Tactile wearing performance of the wool/nylon(50/50%) fabric from fabric mechanical properties measured by FAST system was better than that of the wool 100% fabric. The dimensional stability of the wool/nylon(50/50%) fabric was more stable than that of the wool 100% fabric. Because relaxation shrinkage was lower and hygral expansion of wool 100% fabric was more high. However, the breathability and pilling property of the wool/nylon(50/50%) fabric were inferior than those of the wool 100% fabric. The possibility of application for tra-biz garment of wool/nylon(50/50%) blend fabric was observed because of good heat keepability, tactile wearing performance and washing fastness.