• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.65-70
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• 1993

The effect of particle size of Al powder, water repellent agent and finishing agent on frost resistance, absorption ratio and structure of micropore was examined to improve the physical properties and durability of ALC. According as the amount added of water repellent agent was increased, frost resistance was improved and absorption ratio was decreased. From one side freezing /thaw test, finishing agent which has a low vapor permeation located the crack at close indoor point of ALC specimen. ALC produced from fine Al powder has a low volume reduction by scalling and a sound appearance after freezing/thawing test and top surface freezing test, The crystal of tobermorite in ALC matrix was converted to calcium carbonate by carbonation which was accelerated with the decreasing of water content. Since the micropore of ALC was filled up by calcium carbonate, void ratio was reduced and crack was detected after complete carbonation.

• Journal of the Korean Ceramic Society
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• v.27 no.5
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• pp.589-596
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• 1990

In this study, the freezing and thawing resistance in sea-water of hardened cement paste was investigated by adding slag, diatomaceous earth and fly ash as blending materials and air entraining agent and superplasticizer as admixtures to the cement paste. The structure of hardened cement pate was densified by potential hydraulic properties and pozzolan reactivities of materials and the freezing and thawing resistance of the paste was improved with the effect blending materials and admixtures. As the blending materials were added to the paste, the quantity of C3A was relatively reduced and the formation of expansive ettringite was suppressed to decrease the penetration of sea-water or Cl-, SO42-ion, and then freeze-thaw resistance was enhanced. Particulary, when 40% of slag was mixed, the resistance was excellent.

• 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.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.873-882
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• 2021

In this study, a study was conducted to develop a system for predicting/responding to black ice occurring on roads in winter. Tests conditions were studied by making models of cement concrete pavement and asphalt concrete pavement. In order to freeze water on the manufactured model package, an tests was conducted at a temperature below zero using a freezer, and the freezing process was photographed using a thermal imaging camera. Black ice is generated when water is present on the road surface and the temperature is below freezing or the road surface temperature is below the dew point temperature. Under sub-zero conditions, the pavement, water, and ice were classified with a thermal imaging camera. As a result of the tests, it was possible to distinguish with a thermal imaging camera at a temperature below freezing in the same freezer due to the difference in the emissivity of the packaging, water, and ice. In the process of changing from water to ice during the tests, it was analyzed that ice and water were clearly distinguished by the thermal imaging camera due to the difference in emissivity and reflectance, so black ice could be predicted using the thermal imaging camera.

• Korean Journal of Food Science and Technology
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• v.35 no.1
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• pp.57-61
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• 2003

Variations in NMR relaxation time during freezing and thawing processes in pork loins were investigated. Continuous distribution analysis of data obtained from $T_2\;CPMG$ were carried out to observe the changes in water content in the muscles. Solid fat content slightly increased with decreasing temperature, then showed sharp increase at $-4^{\circ}C$, reaching 85% at $-25^{\circ}C$. Relaxation time decreased with decreasing temperature, suggesting that ice crystals gradually formed at freezing temperature. $T_2$ relaxation time during thawing was higher than that during freezing, suggesting that ice crystals melted by thawing and resulted in water loss from meat. Continuous distribution analysis of data obtained from Carr-Purcell-Meiboom-Gill experiments shows one to four components on the spectra during freezing and thawing processes. The area of major components between 30 to 45 ms decreased with decreasing temperature, and were not detected below $-4^{\circ}C$, below which only $T_s$ signal was detected. The area of $T_s$ decreased with decreasing temperature. Between -4 to $10^{\circ}C$, the areas of $T_m$ and $T_l$ during thawing were larger than those during freezing. These results suggest that the exchange between bound water and free water takes place during freezing and thawing.

• 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.

• Journal of the Korean Geosynthetics Society
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• v.12 no.2
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• pp.13-23
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• 2013

The Korean Peninsula is considered as a seasonal frozen area that is thawed in the spring and frozen in the winter. The influence of fines of the frost susceptibility of subgrade soils were established by laboratory freezing tests simulating closely the thermal conditions in the field. During the winter season, the climate is heavily influenced by the cold and dry continental high pressure. Because of siberian air mass, the temperature of January is $-6{\sim}-7^{\circ}C$ on average. This chilly weather generate the frost heaving by freezing the moisture of soil and damage potential of the geotechnical structure. In the freezing soil, the ice lenses increase the freeze portion of soil by absorbing the ground water with capillary action. However, the capillary characteristics differ from the sort of soil on the state of freezing condition. In this study, ten soil samples are prepared. The basic physical property tests were performed by following the Korean Industrial Standard and the soil specimens were classified by the Unified Soil Classification System (USCS). These classified soils are used to perform the laboratory opened systems freezing test in order to determine the frost heaving characteristics of soils such as unfrozen water content, heaving amount, and freezing depth.

• Journal of the Korean Geotechnical Society
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• v.26 no.7
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• pp.71-80
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• 2010

Korea is considered to be a seasonal frozen soil area that thaws in the spring, and freezes in winter. In the current design codes for anti-freezing layer, the thickness of anti-freezing layer is calculated by the depth frozen due to the temperature condition. Therefore, there is a tendency of over-design and applying uniform thickness without the consideration of thermal stability, bearing capacity and frost susceptibility of materials. So, it is essential to study the structural appropriateness of pavement layer and bearing capacity besides the seasonal and mechanical properties of pavement materials to take an appropriate and reasonable design of the road structure. In this paper, the evaluation of frost susceptibility on subgrade, ant-freezing layer, subbase was conducted by means of the mechanical characteristics and model experiment. The temperature, heaving amount, unfrozen water contents and freezing depth of soil samples, the subgrade, anti-freezing layer, subbase soils of road construction site were measured to determine the frost susceptibility.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.447-452
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• 1988

In order to study effect of freezing rates on the quality changes such as pH, TBA value, free fatty acids and protein extractability, cylindrical chopped beef logs with 10cm of diameter and 10cm of height were frozen at three freezing rates(0.97cm/hr, 2.05cm/hr, 3.71cm/hr)using air blast freezer. Physicochemical changes of frozen meat were investigated during forzen storage at $-20^{\circ}C$ for 16weeks. Results on pH change showed $0.1{\sim}0.2unit$ increase at the 16th week of the frozen storage and the change was smaller with the increasing freezing rates. Free fatty acids content and TBA value also were increased during forzen storage, but they were minimal at 3.71cm/hr freezing rate. Correlation coefficient between TBA value and free fatty acids content were highly significant(r=0.804). After 16weeks of storage, extractibilities of salt soluble protein were decreased by 17.7%, 6.1% and 1.6% at freezing rates of 0.97, 2.05 and 3.71cm/hr, respectively. On the other hand, extractabilities of water soluble protein were decreased by 26.0%, 21.2% and 18.5%, respectively. The effect of freezing rates on the protein extractability appeared to be greater in salt soluble protein than in water soluble protein, but freezing denaturation was more rapid in water soluble protein.

• Journal of Environmental Science International
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• v.26 no.7
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• pp.827-836
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• 2017

Freezing rain is a phenomenon when precipitation falls as a liquid rain drop, but freezes when it comes into contact with surfaces or objects. In this study, we investigated the predictability of freezing rain and its characteristics, which are strongly related with the occurrence of black ice using synoptic scale meteorological observation data. Two different cases occurred at 2012 were analyzed and in the presented cases, freezing rain often occurs in the low-level low pressure with the warm front. The warm front due to the lower cyclone make suitable environment in which snow falling from the upper layer can change into supercooled water. The $0^{\circ}C$ temperature line to generate supercooling water is located at an altitude of 850 hPa in the vertical temperature distribution. And the ground temperature remained below zero, as is commonly known as a condition for black ice formation. It is confirmed that the formation rate of freezing rain is higher when the thickness after 1000-850 hPa is 1290-1310 m and the thickness of 850-700 hPa layer is larger than 1540 m in both cases. It can also be used to predict and estimate the generation of freezing rain by detecting and analyzing bright bands in radar observation.