• Title/Summary/Keyword: Freezing Characteristics

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Frost Heaving Pressure Characteristics of Frozen soils with Frost-Susceptibility and Degree of Saturation (흙의 동상민감성과 포화도를 고려한 동상팽창압 특성)

  • 신은철;박정준;김종인
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.329-336
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    • 2002
  • The earth structures and in-ground LNG tank, and buildings can be constructed with using artificial freezing method on the reclaimed land. In this study, upon freezing a saturated soil in a closed-system from the top, a considerable pressure was developed. The pressure is the result of the surface energy of a curved ice-water interface. The most significant of these parameters will have the greatest effect on the classification. In order to establish frost-susceptibility criteria based on frost heaving expansion pressure, more soils have to be tested. This study was initiated to investigate the soils frost heaving expansion pressure and moisture characteristics resulting from freezing and freezing-thawing cycle process. Weathered granite soils, sandy soil, sandy soil were used in the laboratory freezing test subjected to thermal gradients under closed- systems.

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Evaluation of durability performance for maintenance of tunnel structures due to repeated freezing and thawing

  • Jai-Wook An;Joon-Shik Moon;Hong-Kyoon Kim
    • Geomechanics and Engineering
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    • v.38 no.6
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    • pp.593-601
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    • 2024
  • In this paper, the quantitative evaluation method is presented for the durability performance of mountain tunnel concrete linings experiencing freezing and thawing during winter season. To analyze the freeze-thaw characteristics of lining, the freezing time of the concrete lining was measured by the outside temperature. The heat flow analysis was conducted based on the freezing time measured through the indoor experiment, and based on this, the energy required to freeze the concrete lining by the temperature of the outside air could be analyzed. In addition, the temperature change during the winter season was measured through an instrument installed on the actual tunnel concrete lining, and based on the results of indoor and field experiments, criteria for freeze-thaw environment evaluation and progress evaluation were prepared. Also, an equation using the freezing index was proposed through regression analysis.

Characteristics of Frost Heaving to Grain Size and Permeability of Aggregate Materials (골재의 입도변화에 따른 투수 및 동상특성)

  • Chae, Chang-Woo;Lee, Jun-Heon;Lee, Ju-Hyeong;Lee, Myung-Gu;Song, Chang-Seob
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09a
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    • pp.1103-1109
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    • 2010
  • In this paper in order to analyze the mechanical properties, the permeability and the freezing properties of SB-2 materials which are mainly used with the subbase materials on the rod. For this ends, a series of the physical test, the permeability test and the freezing test were carried out the samples mixed the small aggregate and the big aggregate from which was re-classified the SB-2. From the test results, it was analyzed the characteristics of permeability and the characteristics of freezing of the samples.

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An Experimental Study on the Freezing and Thawing Resistance of Mortar Influenced by Steam Curing Conditions (증기양생조건이 시멘트 모르타르의 동결융해저항성에 미치는 영향)

  • Jang, Moon-Ki;Park, Kwang-Su;Kim, Kwan-Ho;Yoon, Seong-Soo
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2001.10a
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    • pp.185-188
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    • 2001
  • In this study, the characteristics of freezing and thawing resistance, the compressive strength, and the change in height of cement mortar according to a steam and taler curing conditions has been studied. To this end, the major test variables include the period of the early curing, curing temperature and the later curing. The strength test as well as volume variousness have been conducted to explore the characteristics of freezing and thawing resistance on the curing conditions. The experimental results can be efficiently used to improve the characteristics of freezing and thawing resistance for concrete products carrying steam curing.

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Color Characteristics of Soybeans as Influenced by Freezing and Cooking Conditions

  • Lee, Jun-Ho;Seog, Eun-Ju;Park, Yong-Hee
    • Preventive Nutrition and Food Science
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    • v.3 no.2
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    • pp.105-110
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    • 1998
  • Color characteristic of thawed samples of frozen cooked soybean pree of selected cultivar (Gomultong) depending upon cooking temperature an dtime as well as freezing conditions were evaluated . Samples were either cooled in 4$^{\circ}C$ refrigerator (control), or frozen at - 4$0^{\circ}C$ deep freezer for 12 hrs and then stored in 4 $^{\circ}C$ refrigerator , or immersed in liquid nitrogen (LN2) and then each samples were cooked for 5, 10, 20 and 40 min at 65, 80 and 95$^{\circ}C$, respectively. Freezing effect was not significant for all color characteristics except for b. Significant cooking temperature by cooking time interacts were found for all characteristics excepts for L.

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Prediction of Freezing Time for Peeled Chestnut using Finite Difference Method (유한차분법을 이용한 깐밤의 동결시간 예측)

  • Lee, Choong-Ho;Kim, Jong-Hoon
    • Journal of Biosystems Engineering
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    • v.33 no.1
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    • pp.21-29
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    • 2008
  • In this study, the thermal properties of peeled chestnuts were measured, and the mathematical prediction model of freezing time was also developed for various interior positions from center to rind (surface). The measured thermal properties were showed that heat conductivity is $0.43W/m^{\circ}C$, specific heat is $2.7206J/m^3^{\circ}C$, latent heat is $216.9{\times}10^6J/m^3$ and freezing point is $-2.8^{\circ}C$. The entire process about reaching to the freezing time of peeled chestnuts was analyzed with its each regular depth position using the finite difference method (FDM) based on computer simulation. In case of regular freezing temperature, it was showed an that surface (rind) position is more rapidly reached into the freezing point rather than the center position, and also reaching time to the freezing point is more fast at the lower freezing temperature. Comparison results between simulation and experiments showed linear relationship. In regularly varying condition for freezing temperature, this method would give an information to predict a freezing time of the interior points for peeled chestnuts and more similar agricultural products.

An Experimental Study on Sea Water Freezing behavior in a Rectangular vessel Cooled From Above (구형용기의 상부면 냉각에 의한 해수 동결거동의 실험적 연구)

  • 최부홍
    • Journal of Advanced Marine Engineering and Technology
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    • v.22 no.4
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    • pp.529-537
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    • 1998
  • Currently as due to the rapid development of industry and increase in population we meet serious problems concerning the shortage and pollution of water. In the country many experts predict a shortage of water approaching 450 million tons by the year 2006. To cope with this serious problem it is necessary to construct desalination plants. In the adoption of a desalination system the most important factor is the cost of fresh water production,. In general LNG is stored in a tank as a liquid state below $-162^{\circ}C$. When it is serviced, however the LNG absorbs energy from a heat source and transforms to a high pressure gaseous state. During this process a huge amount of cold energy accumulated in cooling LNG is wasted. This wasted cold energy can be utilized to produce fresh water by using a sea water freezing desalination system. In order to develop a sea water freezing desalination system and to establish its design technique qualitative and quantitative data regarding the freezing behavior of sea water is required in advance, The goals of this study are to reveal the freezing behavior of sea water is required in advance. The goals of this study are to reveal the freezing mechanisms of sea water to measure the freezing rate and to investigate the freezing heat-transfer characteristics,. The experimental results will provide a general understanding of sea water freezing behavior in a rectangular vessel cooled from above.

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The Freezing -Thawing Characteristics of Soilcrete (Soilcrete 의 동결융해 특성)

  • 송창섭;반창현;장웅희
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 1999.10c
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    • pp.625-631
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    • 1999
  • In this study, a series of test was conducted to show the characteristics of freezing -thawing process on soilcrete using the soft clay in a redevelopment paddy area, was treated with cement and several additives such as Beestar, CaSO4 , MgO, and polypropylene fiber, From the results of test, it was found that first addtivies -cement and beestar-was effective for compressive strength, and the resistance against freezing -thawing process was improved by secondary additives, in the order their effectiveness, i.e. CaSO4 , Synthetic fiber, MgO and Beestar.

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Effect mechanism of unfrozen water on the frozen soil-structure interface during the freezing-thawing process

  • Tang, Liyun;Du, Yang;Liu, Lang;Jin, Long;Yang, Liujun;Li, Guoyu
    • Geomechanics and Engineering
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    • v.22 no.3
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    • pp.245-254
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    • 2020
  • The interaction between the frozen soil and building structures deteriorates with the increasing temperature. A nuclear magnetic resonance (NMR) stratification test was conducted with respect to the unfrozen water content on the interface and a shear test was conducted on the frozen soil-structure interface to explore the shear characteristics of the frozen soil-structure interface and its failure mechanism during the thawing process. The test results showed that the unfrozen water at the interface during the thawing process can be clearly distributed in three stages, i.e., freezing, phase transition, and thawing, and that the shear strength of the interface decreases as the unfrozen water content increases. The internal friction angle and cohesive force display a change law of "as one falls, the other rises," and the minimum internal friction angle and maximum cohesive force can be observed at -1℃. In addition, the change characteristics of the interface strength parameters during the freezing process were compared, and the differences between the interface shear characteristics and failure mechanisms during the frozen soil-structure interface freezing-thawing process were discussed. The shear strength parameters of the interface was subjected to different changes during the freezing-thawing process because of the different interaction mechanisms of the molecular structures of ice and water in case of the ice-water phase transition of the test sample during the freezing-thawing process.

Effect of Freezing on Hydration Rate and Sprouting Characteristics of Soybeans (대두의 수화속도와 콩나물의 발아특성에 대한 동결처리 효과)

  • Rhim, Jong-Whan;Oh, Bong-Yun;Kim, Dong-Han;Ham, Kyung-Sik
    • Korean Journal of Food Science and Technology
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    • v.35 no.4
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    • pp.660-665
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    • 2003
  • Effect of freezing on the hydration rate and growth characteristics of bean sprout of two domestic cultivars of soybean, Eunha beans and Taegwang beans, was investigated. Freezing of the soybeans at $-80^{\circ}C$ affected characteristics of the hydration and growth of soybean sprout of the beans. Hydration rate of the frozen beans depended on the hydration temperature. It decreased up to 50% at lower than $60^{\circ}C$ of hydration temperature, but it did not decrease at higher than $60^{\circ}C$. Activation energies of frozen Eunha and Taegwang beans were 39.79 and 39.25 kJ/mol, respectively. Kinetic compensation effect between activation energy values and the pre-exponential factor for the hydration of soybeans with or without freezing was observed. Germination rate and thickness of the bean sprout increased by freezing, however, yield and weight were not affected by freezing.