• Title/Summary/Keyword: 내한촉진제

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A Experimental Study on Early Age Compressive Strength of Cement Mortar Using Anti Freezer and Hardening Accelerator at low temperature (방동제와 경화촉진제를 사용한 저온환경하 모르타르의 초기압축강도에 관한 실험적 연구)

  • Kim, Mok-Kyu;Lee, Han-Seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.11a
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    • pp.135-136
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    • 2014
  • In this study, the experimental study on the early age compressive strength of cement mortar using anti freezer and hardening accelerator at low temperature was conducted. For this study, all of materials for experiment were kept in a low temperature for 24 hours before mortar mixing. After mortar curing at low temperature, compressive strength was measured at the early ages. Furthermore, properties of hardened cement material was analysed using TG-DTA and MIP.

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A Study on the Strength Properties of Mortar Under Various Types and Contents of Accelerators for Freezing Resistance (내한촉진제의 종류 및 혼입양 변화에 따른 모르터의 강도특성에 관한 연구)

  • Lee, Sang-Soo;Won, Cheol;Park, Sang-Joon;Kim, Dong-Seok
    • Journal of the Korea Institute of Building Construction
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    • v.2 no.2
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    • pp.151-156
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    • 2002
  • When fresh concrete is exposed to low temperature, the concrete may suffer frost damage due to freezing at early ages and strength development may be delayed. One of the solution methods for resolve these problems is to reduce freezing temperature of concrete by the use of chemical admixture called Accelerators for freezing resistance. In this study, we investigate the effect on strength development of cement mortar using accelerators for freezing resistance with the variance curing condition. As the result of this study, the mortar using accelerators for freezing resistance show that continuously strength development in curing condition of -5$^{\circ}C$. And compressive strength under the variance temperature condition was higher than constant temperature condition in same maturity.

A Study on the improvement of Strength delay according to Low Temperature of Cold Weather Concrete (한중콘크리트의 저온에 의한 강도지연 개선연구)

  • Lee, Sang-Soo
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.7 no.1
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    • pp.51-59
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    • 2012
  • The cold weather concrete poured in the winter season can cause the problem of the Due to recent high-rise building is made. In this research, the nominal mix of the early strength in concrete tried to be set through the mixing proportion experiment for each empirical variable and each component strength properties for the early strength improvement tries to be examined. In the cold weather concrete experiment, the cement and high early strength (type3) cement improving in OPC than OPC was excellent. The polycarboxylic acid based compound was exposed to be excellent in the intensity revelation properties. Because the using of the fly ash was disadvantageous it was excluded from this experiment. It showed the optimum temperature for the intensity revelation up over $12^{\circ}C$.

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The Effect on Strength Development of Cement Mortar using Accelerators for Freezing Resistance with the Curing Condition (양생조건이 내한촉진제를 사용한 시멘트 모르타르의 강도증진에 미치는 영향에 관한 연구)

  • Won, Cheol;Kim, Dong-Seok;Park, Sang-Joon;Lee, Sang-Soo;Kim, Young-Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.533-536
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    • 2001
  • When fresh concrete is exposed to low temperature, the concrete may suffer frost damage due to freezing at early ages and strength development may be delayed. One of the solution methods for resolving these problems is to reduce freezing temperature of concrete by the use of chemical admixture called Accelerators for freezing resistance. In this study, we investigate the effect on strength development of cement mortar using accelerators for freezing resistance with the variance curing condition. As the result of this study, the mortar using accelerators for freezing resistance show that continuously strength development in curing condition of -5$^{\circ}C$. And compressive strength under the variance temperature condition was higher than fixed temperature condition in same maturity.

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A Study on the Freezing and Strength Properties of Cement Mortar using Accelerator for Freezing Resistance (내한촉진제를 이용한 시멘트 모르터의 동결 및 강도특성에 관한 연구)

  • 박상준;김동석;원철;이상수;김영진
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.10b
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    • pp.1267-1272
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    • 2000
  • When fresh concrete is exposed to low temperature, the concrete may suffer frost damage due to freezing at early ages and strength development may be delayed. These are problems on cold weather concrete. One of the solution methods for resolving these problems has been to reduce the freezing temperature of concrete by the use of chemical admixtures called Accelerators for freezing resistance. Therefore, in this study, we executed freezing temperature of mortar, setting and strength properties with using water reducing accelerator and accelerators for freezing resistance which are producted internationally. As a result of this experiment, the freezing temperature of mortar is lower and the setting property is promoted when the admixing content of accelerators for freezing resistance is increased. Moreover, the compressive strength of mortar used accelerators for freezing resistance represented the result which is similar with result of analysis of compressive strength increase with using logistic curve formula, but in the case of plain and using water reducing accelerator, there is no relation between logistic curve formula, maturity and compressive strength.

A Study on the Strength Properties and the Temperature Hysteresis of Winter Concrete according to the difference of Curing Method in Mock-up Test (실물대시험에서의 양생방법 차이에 따른 한중콘크리트의 온도이력 및 강도특성에 관한 연구)

  • Won, Cheol;Han, Cheon-Goo
    • Journal of the Korea Institute of Building Construction
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    • v.3 no.4
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    • pp.87-94
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    • 2003
  • This study is to investigate the temperature hysteresis and development of compressive strength due to the curing conditions and to evaluate the optimum curing condition of test specimens showing the same development of strength to that of real structures in cold weather. The results of temperature curve with curing conditions in mock-up tests showed the trend of decrease plain concrete with insulation form, plain concrete with heating, concrete with accelerator for freeze protection, and control concrete in turn. The strength development of plain concrete of inside and outside of shelter showed the very slow strength gains due to early freezing, but that of concrete with accelerator for freeze protection showed the gradual increase of strength with time. From this, it is clear that accelerator for freeze protection has the effects of refusing the freezing temperature and accelerating the hardening under low temperature. Strength test results of small specimens embedded in members and located in insulation boxes at the site are similar to that of cores drilled from the members at the same ages, thus it is clear that these curing methods are effective for evaluating in-place concrete strength

Effect of Covering Materials of Ventilating Non-Woven Fabric and $GA_3$ on the Growth and Yield in the Leaf Lettuce during Low temperature (통기성 부직포의 피복자재 및 $GA_3$처리가 저온기에 잎상추의 생육 및 수량에 미치는 영향)

  • 안종길;최영환;빈기효홍
    • Proceedings of the Korean Society for Bio-Environment Control Conference
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    • 2002.04a
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    • pp.13-19
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    • 2002
  • 우리나라에서는 결구상추보다 잎상추가 주로 재배되고 있고 특히 잎상추는 내한성이 강하여 $0^{\circ}C$에서도 잘 견디고 5$^{\circ}C$ 이상이면 겨울 저온기에도 무난방 재배가 가능하나 피복자재와 피복 노력 등의 비용이 많이 들고, 또 온도 환경이 불량하여 단경기 생산이 불가능하게 되어 주년 재배가 어렵게 되므로 저온기에 효과적인 보온 방법과 생장조절제처리로 엽채류의 생육 촉진 및 품질을 향상시킬 수 있는 방법이 필히 구명되어야 할 과제라고 생각된다. (중략)

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The Freezing Temperature of Chemical Admixtures for Concrete and the Quality Vareation of Concrete Using the Frozen Admixtures (콘크리트용 혼화제의 동결온도 및 동결된 혼화제의 사용에 따른 콘크리트의 품질변화)

  • 한천구;한경익;이건철
    • Magazine of the Korea Concrete Institute
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    • v.10 no.4
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    • pp.205-212
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    • 1998
  • Frost damage of a storage tank for chemical admixtures caused by a low temperature in winter and quality deterioration of chemical admixtures have been often reported. However, there have been few regulations and researches related to the frost damage of chemical admixtures and facilities. Therefore, this paper is intend to investigate not only, the freezing points of chemical admixtures such as AE admixtures and water-reducing AE admixtures, etc., but also the quality variation of concrete used with chemical admixtures before freezing and after freeze-thaw cycles. According to the results of experiments, most chemical admixtures except anti-freezing agent and accelerating water-reducing AE admixtures should be kept from being frozen in low winter temperatures. However, full agitation of frozen chemical admixtures dose not cause the problems of concrete related to the quality of chemical admixtures.

감귤과피 유색미의 취반 특성

  • 서성수;노홍균;윤광섭;김순동
    • Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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    • 2003.10a
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    • pp.157-157
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    • 2003
  • 우리나라에서 생산되는 감귤은 지리적 기후 조건으로 내한성이 강한 만다린계 온주밀감이 주종을 이루나 최근 과잉생산으로 인한 가격하락과 수입자유화에 따른 대처의 일환으로 경쟁력이 높은 품종을 장려 보급하고 있다. 감귤의 국내 연간 생산량은 56만 톤으로 과일 전체 생산량의 약 30%를 차지하며 과실의 약 20%가 과피로서 그 일부가 한약재로 쓰이나 대부분이 버려지고 있다. 감귤의 과피에는 carotenoids, bioflavonoids, pectin 및 terpenes가 풍부하게 함유되어 있으며, 천연에서 발견되고 있는 약 300여종의 carotenoids계 색소 중 115종이 감귤에 존재한다. 감귤 과피의 주요 carotenoids로는 비타민 A의 역할을 하는 $\beta$-carotene과 cryptoxanthin을 비롯한 $\beta$-citraurin이며 천연 착색제로 활용되고 있다. 또, 주요 bioflavonoids로는 모세혈관의 수축을 촉진시켜 고혈압 예방과 이로 인한 각종 질환을 방지하는 작용을 가진 hesperidin과 혈액내 LDL 콜레스테롤의 양을 줄이는 작용이 알려진 naringin이 있다. 그 외의 감귤 flavonoids도 항산화작용, antimutagen 활성, 항암, 항알레르기 및 항바이러스 효과가 알려져 있다. 밀감 과피의 bioflavonoids는 약 60여종이 분리되어 그 구조가 밝혀져 있으나 90% 이상이 hesperidin이다. 또 과피유에는 $\delta$-limonene을 주성분으로 하는 휘발성 향미성분이 함유되어 있어 향미 개선제로서의 활용이 기대되고 있다. 본 연구는 최근 식생활의 서구화로 쌀 위주의 식생활에 많은 변화를 가져와 쌀 소비량은 해마다 줄어들고 있는 반면 기능성을 가미한 쌀의 소비가 늘고 있음을 감안하여, 우리나라 제주도에서 생산되고 있는 감귤 과피의 물 균질액을 쌀에 코팅하여 아름다운 색상과 기능성을 지닌 유색미를 제조함과 동시에 그 취반 특성을 조사하였다. 그 결과 유색미의 색상은 진노랑(L*; 63.6, a*; -7.87, b*; 46.35)으로 취반 후에도 유사한 색상을 나타내었다. Total carotenoids는 감귤과피에서는 10.74mg%, 과피의 물 균질액에는 0.46mg%이었으며 유색미에는 0.l2mg%, 유색미 취반에는 0.05mg%를 나타내었다. Hesperidin은 과피, 물 균질액, 유색미 및 유색미 취반에서 각각 2173.l2mg%, 108.65mg%, 21.73mg% 및 8.67mg%이었으며, naringin은 각각 1468.40mg%, 73.38mg%, 14.62mg% 및 5.87mg%를 나타내었다. 감귤과피의 유리아미노산은 asparagine이 94.22mg%로 가장 높았으며, methionine이 24.88mg%, alanine이 19.64mg%, ${\gamma}$ -aminoisobutylic acid가 15.37mg%로 이들 4종의 아미노산이 전체 유리아미노산함량의 70%를 나타내었다. 유색미 취반에는 백미 취반에 비하여 총 유리아미노산의 함량이 15%정도 증가되었으며, 그 중에서 glutamic acid는 2.5 배가 증가되었다. 감귤과피의 주요 무기질은 K(652.60mg%)와 Ca(222.50mg%)로 전체 무기질 함량의 86%를 차지하였으며 유색미 취반은 백미 취반에 비하여 K는 2.3배, Mn는 76%, Ca, P, Mg은 16~26%, Fe는 13%가 각각 증가되었다. 취반의 경도, 점착성 및 깨짐성은 유색미 취반과 백미 취반간에 차이가 없으나 응집성과 탄력성은 유색미 취반에서 높았다. 색상에 대한 기호도, 구수한 맛 및 종합적인 기호도는 유색미 취반에서 높았으며 단맛, 쓴맛은 백미 취반과 차이를 보이지 않았다.

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