• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.177-180
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• 2006

Reinforced concrete has been widely used as a semi-permanent construction materials. However, sea sand, deicing salt, and marine condition might induce the corrosion of embedded reinforcement due to the penetration of chlorides in concrete structures. This reinforcement corrosion causes serious problems on safety and serviceability of structures during lifetime. Also, reinforcement corrosion may cause the collapse of structures in worst case, so that the corrosion problem is more and more intensely growing. The purpose of this paper is to provide the fundamental data for the mechanical effect of corrosion through evaluation on bond characteristics of reinforced concrete using corroded bars.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.718-723
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• 2000

Reinforced concrete is in general, known as high durability construction material under normal environments due to strong alkalinity of cement. It is, however, well known that moderate or minor cracks in reinforced concrete should be most serious causes to deteriorate the durability of RC structures. Futhermore, chloride contents penetrating through unexpected cracks in reinforced concrete bridges get to weaken corrosion resistance of reinforcement steel in concrete and then to accelerate the deterioration of concrete durability. The objective of this experimental research is 1) to evaluate the effect of various corrosion protection systems for reinforced concrete specimens with moderate or minor cracks which are exposed to cyclic wet and dry seawater, and then 2) to develop effective corrosion protection systems for reinforced concrete bridges under the exposure of various detrimental environments such as seawater, deicing and etc.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.212-213
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• 2018

The cementitious composites have been developed to satisfy various demands of the construction market. The conductive concrete, which is a carbon-based cementitious composite, was used for the deicing or the detecting the internal crack. The cement-based battery is a technology that applies the basic concept of the alkaline battery to these conductive concretes. The cementitious composites could have a function as batteries, through a mixing of anode and cathode, which were consist of the zinc and manganese dioxide powder. The carbon-based materials, which have a significant effect on electrical properties, could be considered as the main variable in cement-based batteries. Therefore, in this study, the effects of carbon-based materials were investigated. Two types of materials, including the Carbon black and Multi-walled carbon nanotube(MWCNT), were considered as the main variables. From the experiment results, the electrical characteristics such as resistance, voltage, and current were compared according to the age.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.177-180
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• 2005

Decing agent with chloride promote frost damage of concrete structure in winter period. From the safetyside, however, it is difficult to stop using chloride. Therefore, the durable concrete is required from now on. In this paper, long-term freezing and thawing test was carried out using the freezing water containing $CaCl_{2}$ to consider the concrete scaling according to the kind of binders, such as OPC, Flyash, Slag+Fa. and Slag As a result, it was found that the degree of scaling is different with containing slag being considered to prevent the penetration chloride ion and according to each binders.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2256-2261
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• 2008

The electric snow melting and deicing system by electric heating cable which is adopted in this study is a part of road facilities to keep surface temperature of the road higher than freezing point of water for melting the snow or ice accumulated on it. The electric heating cables are buried under paved road at a certain depth and a certain pitch and operated automatically and manually. Design theory, amount of heating, and installation standard vary according to economic situation, weather condition, and installation place. A main purpose of this study is figuring out the appropriate range of required heat capacity and installation depth and pitches for solving snowdrifts and freezing problems with minimum electric power consumption. This study was performed under the ambient air temperature($-2^{\circ}C$, $-5^{\circ}C$), the pitches of the electric heating cables (200 mm, 300 mm), heating value ($250\;W/m^2$, $300\;W/m^2$, $350\;W/m^2$).

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2008.11a
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• pp.31-31
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• 2008

복합 싸이클 시험 모니터링을 통해 NaCl, $CaCl_2$ 제설염 환경에서 11 % Cr, 17 % Cr 페라이트 스테인리스강의 외면부식특성을 조사하고자 하였다. 용액 내 NaCl 및 $CaCl_2$의 농도가 증가함에 따라 용액의 pH가 떨어졌으며, $CaCl_2$의 농도증가에 따른 산성화도가 NaCl에 비해 크게 나타났다. 염수분무-건조-습윤 과정의 반복으로 구성되어 있는 복합싸이클 시험 중 소재의 표면상태 변화를 모니터링 한 결과, 건조 과정 중에 공식이 시작되며, NaCl 환경의 경우엔 습윤과정 중에 $CaCl_2$ 환경의 경우엔 건조 중에 공식성장이 주로 이루어지는 것으로 확인되었다.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.6
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• pp.29-36
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• 2008

This study examined the de-icing agents' stresses on Pinus strobus and Pinus thunbergii by chlorophyll fluorescence analysis. The assumption of this study was that photosynthetic efficiency was changed by de-icing agents applied onto highways in winter by altering the concentration of the de-icier, types of de-icer and leaf surface coating liquid application. The practical purpose of this study was to investigate the de-icing gents stresses on Pinus strobus by the highway area where de-icing agents were used frequently and to discover out minimizing stratages to prevent further damages. or this simulation study, a sample plot was established in Bogae-myeon, Anseong, Gyeonggi-do and Pinus strobus and Pinus thunbergii were planted for the examination in April, 2005. Five types of de-icing agents - NaCl, $CaCl_2$, T product(NS40:low cWoride de-icer type), NaCl+$CaCl_2$ and T product+$CaCl_2$ - were selected and the their concentration was altered to 0%, 5%, and 9%. Five types of de-icing agents were applied to both trees treated by a leaf surface coating liquid and trees not treated by leaf surface coating liquid. For the fluorescence analysis, the leaf surface coating liquid, which was diluted by 10 times, was sprkinkled onto the two tree species three days prior to gathering samples. Sample leaves from the two tree species were gathered at 10 o'clock in the morning of mid-August, 2006 and brought to the laboratory within three hours to be dipped in different concentrations (0%, 5%, or 9%) of the five de-icing agents for two minutes. Then the eaves were placed on the filter paper dipped in each solution on a petri dish, sealed with polyethylene film and kept in a growth chamber at $22^{\circ}C$ for 72 hours. Out of the growth chamber, the leaves were treated with a chorophyll fluorescence reaction analyzer for 30 minutes to measure the initial light acceptance rate(Fo), maximum light acceptance ate(Fv/Fm), light acceptance usage(F' q/F' m) and optical electron delivery coefficient(qP). As a result, Pinus strobus' initial light acceptance rate(Fo) decreased as T product and NaCl increased in concentration, and $Cal_2$ did not reduce much with the eaf surface coating liquid application. Maximum light acceptance rate(Fv/Fm) and light acceptance usage(F' q/F' m) decreased sharply as T product and NaCl increased in concentration and NaCl+$CaCl_2$ and T product+$CaCl_2$ did not reduce much with leaf surface coating liquid application. Optical electrons delivery coefficient (qP) decreased as T product increased in concentration on trees without the leaf surface coating liquid application and all other de-icing agents did not show much reduction. As for Pinus thunbergii, the initial light acceptance rate(Fo) decreased as T product increased in concentration, but the maximum light acceptance rate(Fv/Fm) was not reduced much by changes in concentration. light acceptance usage(F' q/F' m) decreased as NaCl increased in concentration and optical electron delivery coefficient(qP) decreased as NaCl increased in concentration in both with and without leaf surface coating liquid application. In conclusion, it was possible to plant Pinus strobus if spraying leaf surface coating liquid or cleaning deicing salt to prevent the damage caused by deicing agents was more economical than replacing the trees. If not, it was better to plant Pinus thunbergii. Another way to decrease the deicing gents stresses of landscape plants would be planting the trees further away from the roads even though it might take longer period to display its planting functions.

• Journal of the Korean GEO-environmental Society
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• v.13 no.2
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• pp.5-17
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• 2012

The amount of snow due to global warming and climate change has recently increased. The effective management of snow removal materials will be required. First, on the basis of domestic winter temperature, it is not necessary to get a baseline to less than the freezing point of $-52^{\circ}C$ for the calcium chloride($CaCl_2$) of 30%.. In terms of cost comparison between calcium chloride($CaCl_2$) and sodium chloride($NaCl$), the calcium chloride($CaCl_2$) is 2 to 3 times more expensive, and the supply of the calcium chloride($CaCl_2$) is not produced in domestic country and is in the conditions that have to imports all needed. Accordingly, the effective use scheme of snow removal materials should be considered to multifaceted ways. Thus, the objective of this study is to develop effective method and to replace from calcium choride($CaCl_2$) to sodium chloride($NaCl$) solution in the current snow removal operating system that uses a pre-wetted salt spreading method. The effective method that equals to the quality of the existing snow removal materials was developed in this study through performance tests for deicing chemicals, corrosion test of steel and freezing and thawing tests of concrete.

• Journal of Korean Society of Forest Science
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• v.105 no.3
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• pp.303-308
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• 2016

To investigate the effect of calcium chloride ($CaCl_2$) using for deicing salts in winter on gas exchange and stomatal responses of 3-year-old Prunus serrulata, we treated twice (1 L) $CaCl_2$ solution (0.5%, 1.0% and 3.0%) in the root zone before leaf unfolding. Stomatal conductance ($g_s$), photosynthetic rate ($P_n$), transpiration rate ($T_r$) and water use efficiency (WUE) in the leaves of P. serrulata were decreased with increasing of $CaCl_2$ concentration. Even though stomatal conductance and photosynthetic rate were reduced by $CaCl_2$, intercellular $CO_2$ concentration ($C_i$) in $CaCl_2$ treatments has similar or higher values compared with control. These results suggest that non-stomatal limitation as well as stomatal limitation induced the reduction of photosynthetic rate together. On the other hands, treatment of $CaCl_2$ before leaf unfolding also affected leaf morphology traits. We proposed that reductions of stomatal length and leaf size and high pore density with increasing salinity is adaptative mechanism to reduce the water loss in plant.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.3
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• pp.1-8
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• 2017

The present study aimed to investigate the effect of calcium chloride($CaCl_2$) on the growth and physiological responses of Pinus strobus and the variables that are sensitive to $CaCl_2$. Thus, changes in the visible damage, growth of root collar diameter, plant water content, chlorophyll content and composition, maximum PS II photochemical efficiency, and electron transport rate of P. strobus was analyzed in relation to treatment witih $CaCl_2$. A $CaCl_2$ solution(0.5, 1.0 and 3.0%) was applied in the root zone before leaf unfolding. Leaf browning, defoliation, and drying were observed with $CaCl_2$ application and this pattern was aggravated as the $CaCl_2$ concentration increased and the treatment period became longer. The decrease of growth in root collar diameter and height and leaf water content were observed at $CaCl_2$ 1.0% and 3.0%. The total chlorophyll content indicated that photopigment, PS II photochemical efficiency and electron transport rate significantly decreased at $CaCl_2$ 3.0%. In conclusion, $CaCl_2$ affected leaf water content and led to a decrease of capability in light harvesting and photochemical responses. Also, as a result of the correlation between calcium chloride concentration and growth and physiological response parameters, it was found that the leaf moisture content and the ratio of chlorophyll a and b reflect the damage level of calcium chloride sensitively because their coefficient of determinations were relatively high.