• Title/Summary/Keyword: freezing index

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A Study on Compute of Freezing Depth through Frost Damage Investigation in Gangwon Region (강원지역 동상 피해조사를 통한 동결심도 산정 연구)

  • Seungwoo Ahn;Beomsu Moon;Woocheol Jeong;Songhee Suk;Song Choi;Yongseong Kim
    • Journal of the Korean Geosynthetics Society
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    • v.22 no.1
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    • pp.97-107
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    • 2023
  • This study analyzed the causes of frost damage and freezing depth for concrete ballast sites in the Gangwon mountainous area, which has a high freezing index, and considered the equation for freezing depth in concrete roadbeds. Comparing the freezing depth tendencies of concrete roadbeds in the Gangwon mountainous area and Gangwon area, it was found that the freezing depth of concrete roadbeds was higher than that of the Gangwon area when the freezing index was less than 400. However, in sections with a freezing index greater than 400, the freezing depth was higher in the Gangwon area than in the concrete roadbeds. This study proposed an equation for computing the freezing depth in the Gangwon area to provide basic data for establishing preventive measures against frost damage during railway and road construction projects in the Gangwon region.

Freezing Depth Analysis Considering Environmental Factors and Physical Properties of Pavement Materials (환경변수 및 도로재료의 특성을 고려한 동결깊이 분석)

  • Kim, Suk Myung;Rhee, Suk Keun;Kim, Suk Nam
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.1D
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    • pp.55-61
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    • 2009
  • In this research freezing depth analyses were performed for the recent 9 project field sites using FrostAM which is a freezing analysis model developed recently within the country and a model based on regional environmental factors and physical properties of pavement materials. The environmental factors needed for freezing depth analysis were obtained from the meteorological agency website. And there were laboratory tests and analyses using a measuring device for properties of unsaturated soil for the field site samples across country to obtain hydrographical properties among physical properties. The freezing depths analyzed by FrostAM were deeper in the range of 14cm~44cm than those based on freezing index. It is considered that the freezing depths based on freezing index were overestimated. And there are considerable differences among the freezing depths based on freezing index which were designed by different designers.

Effects of Freezing Temperature on Quality of Vacuum Packaging Freezed Beef (동결온도가 진공포장 동결육의 품질에 미치는 영향)

  • 정인철;김도완;문귀임;강세주;김기영;문윤희
    • The Korean Journal of Food And Nutrition
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    • v.11 no.4
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    • pp.409-415
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    • 1998
  • This study was carried out to investigate the effects of freezing temperature on quality of vacuum packaging freezed beef. In case of thaw drip loss, the freezing of -3$^{\circ}C$ and -20$^{\circ}C$ were 5.23% and 5.17% to 60 days respectively, were increased significantly during freezing. The cooking loss of water bath and pan were increased significantly during freezing than the beginning of freezing, but were no different between -3$^{\circ}C$ and -20$^{\circ}C$. The salt soluble protein extractability was decreased during freezing, the -20$^{\circ}C$ freezing was higher than -3$^{\circ}C$freezing. The water soluble protein extractability was increased during freezing higher than during freezing. The myoglobin denatured percentage of the -3$^{\circ}C$ freezing was higher than -20$^{\circ}C$ freezing, the 15 days storage of -3$^{\circ}C$ freezing was highest to 96%. The shear force value was not change during freezing, the myofibrillar fragmentation index during freezing was higher than the beginning of freezing, but was not change during freezing. The pH was decreased to freezing 45 days, after that increased.

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A Study on Freezing Characteristics of Pavements Using Data of Test Road (시험도로 자료를 이용한 포장의 동결특성 연구)

  • Jeong, Jin-Hoon;Bae, Sung-Ho;Kwon, Soon-Min
    • International Journal of Highway Engineering
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    • v.7 no.2 s.24
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    • pp.87-95
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    • 2005
  • To prevent the lowering of structural capability due to freezing and thawing in cold winter, numerous researches on frost heaving have been performed. As the result, the freezing index contour map of the Korea peninsula has been made for the design of the anti-freezing layer of pavements. However, the validity of the anti-freezing layer needs to be evaluated because systematic investigations on the variation of freezing depth with the thickness and material types of pavement layers and the configuration of the ground have been rarely performed. The freezing index of the Korea Highway Corporation test road site was calculated and the freezing depths of the concrete and asphalt pavements of the test road were investigated using the ambient and pavement temperature and water content. In addition, the investigated freezing depths were compared to the values estimated by existing freezing depth models. This is the preliminary study on the freezing-related data measured at the test road. The results with higher reliability will be produced by the long-term accumulation of the data and the analysis on it.

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An Experimental Study on Freezing-Thawing Resistance of Concrete Using Ground Granulated Blast-Furnace Slag (고로슬래그 미분말을 사용한 콘크리트의 동결융해 저항성에 대한 실험적 연구)

  • 남용혁;최세규;김동신;김생빈
    • Proceedings of the Korea Concrete Institute Conference
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    • 1996.10a
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    • pp.148-153
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    • 1996
  • Concrete with ground granulated blast-furnace slag can be affected by frost attack because the reaction of hydration is slow at the early age. In this study, therefore, the freezing and thawing test has been carried out to investigate the freezing and thawing resistance on concrete with ground granulated blast-furnace slag. The freezing and thawing test has been performed on concrete a blended cement, which was substituted by ground granulated blast-furnace slag with 4 kinds of ratio (non-admixture, 20%, 40% and 60%). And also tested on concrete added the AE agents to the concrete of same mix proportion to search the improvement effects about the resistance. As a result, the freezing and thawing resistance showed a tendency of reduction in proportion to the increase of the substitution ratio. For non-AE concrete, resistances of the freezing and thawing were very poor as the durability index indicated less than 5.8%. For AE concrte, resistance of the freezing and thawing were excellent as the durability index indicated more than 80.9%.

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A Study on the Analysis of Freezing Soil by Frost Groups and Frost Depth in Korea (우리나라 동결토의 토군별 분석과 동결심도에 관한 연구)

  • 정철호
    • Geotechnical Engineering
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    • v.5 no.4
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    • pp.5-16
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    • 1989
  • This paper statistically analyses the freezing soil by frost group and frost depth in Korea with data from soil testing in the Korea National Housing Corporation, the climate data provided by the Central Weather Office and the data on the frost depth from the National Construction Laboratory Institute. In this paper, freezing variable are analysed such as percentage finer than 0.02 m by weight, plasticity index, freezing index, water contents of soil and frost depth etc‥‥ The result of the analysis is as follows. 1) The frost depth of Korea depends on the properties of soil rather thank the characte fistic of area. 2) The distribution map of design freezing index in 57 cities is drawn up with the maxi- mum freezing index, during past 14 years, calculated by the average of the air temperature observed four times(03 : 00.09 00, 15 : 00, 21 : 00) a day. 3) By correcting the OLS line estimated from the relationship between freezing index and frost depth, a method of utlizing the line with the upper confidence limit of 99.9% int-distribution as predicted maximum frost depth is newly introduced.

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Effect of Freezing Temperature on the Quality of Beef Loin Aged after Thawing (동결온도가 해동후 숙성한 우육의 품질에 미치는 영향)

  • 정인철
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.28 no.4
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    • pp.871-875
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    • 1999
  • This study was carried out to investigate the effects of freezing temperature on the quality of thawing aged beef loin. Drip loss was higher at 3oC freezing than at 20oC freezing, showing 17.21% drip loss after 6 days aging by 3oC freezing, 14.92% drip loss 12 days aging by 20oC freezing. Cooking loss by both water bath and pan boiling were decreased with increased in aging days. The salt soluble protein extractability of the beef loin was increased until 9 days aging by both 3oC and 20oC freezing, after that was decreased. The L value of the beef loin was high until 9 days aging by 3oC freezing, after that the L value of that was decreased. And the aging at 20oC freezing was high significantly with increased aging days. The a value of the beef loin was low significantly in 6 and 9 days aging by 3oC freezing, 20oC freezing was low significantly with increased aging days. The b value of the beginning of aging was higher with increased aging days. The percentage of denatured myoglobin of the beginning of aging was the highest, then those of 3oC and 20oC freezing showed 89.70% and 88.00%, respectively. The shear force of the beef loin was decreased with aging days, but the myofibrillar fragmentation index increased with aging days. The pH of the beef loin increased until 6 days of aging by both 3oC and 20oC freezing, after that the pH decreased.

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Dynamic Behavior of Weathered Granite Soils after Freezing-thawing (화강풍화토의 동결-융해 후의 동적 거동)

  • 윤여원;김세은;강병희;강대성
    • Journal of the Korean Geotechnical Society
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    • v.19 no.5
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    • pp.69-78
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    • 2003
  • In order to investigate the dynamic behavior of weathered granite soils before and after freezing-thawing, cyclic triaxial tests were conducted for the specimens not only with the variation of silt contents within 20% but with plasticity index within 20%. As the results, the dynamic shear modulus of weathered granite soils decreased with increasing silt contents. However, the change in damping ratio was negligible. The influence of freezing-thawing on shear modulus and damping ratio was minimal for the granite soils with variation of silt contents. For the case of the weathered soils with variation of plasticity index, the shear modulus increased with plasticity index within 20%, while the modulus decreased remarkably after freezing-thawing.

Verification of Freezing Index and Frost Penetration Depth with Temperature Data of Korea LTPP (국내 LTPP 온도 자료를 이용한 동결지수와 동결깊이 검증 연구)

  • Kim, Boo-Il;Jeon, Sung-Il;Lee, Moon-Sup;Lim, Kwang-Su
    • International Journal of Highway Engineering
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    • v.11 no.4
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    • pp.143-152
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    • 2009
  • The purpose of this study is to evaluate the freezing index and frost penetration depth. The freezing index and frost penetration depth were analyzed using air temperature and temperature profile of pavement system in Korea LTPP-SPS(Long Term Pavement Performance-Specific Pavement Study) site. The predicted frost penetration depth were then compared with the measured one from the LTPP sites. And the trend of annual freezing index was analyzed using the temperature data of meteorological stations located in the vicinity of Korea LTPP-SPS site. The result showed that the freezing index was rapidly decreased since 1987, and it was known that the use of freezing index determined from the past 30 years temperature data could cause the over estimates in the pavement thickness design. The temperature profile measured at 3 sections of LTPP-SPS sites showed that the temperature of subbase layer was above $0^{\circ}C$, even though anti-frost layers were found in these sections. Comparing the measured and calculated frost depth, the frost depth calculated from the subgrade frost penetration permissible method showed a similar trend with the measured frost depth.

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