• Title/Summary/Keyword: curing temperature.

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An Experimental Study on the Characteristics of Strength in Mortar under High Temperature conditions in an Early Age (초기 고온이력을 받은 시멘트 모르타르의 강도 특성에 관한 실험적 연구)

  • Kim Young Joo;Kim Han Sik;Gong Min Ho;Kim Je Sub;Lee Young Do;Jung Sang Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05b
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    • pp.517-520
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    • 2005
  • This study is basic experiment for estimating influence of strength by curing temperature of concrete's heat of hydration and estimate relationship of compressive strength development by initial curing temperature factor, and then asume temperature factor which influence compressive strength development and for showing basic document of quality control. According to the result of cement mortar by the curing temperature factor high-curing temperature shows high strength on 3 day compare with low curing-temperature, shows higher strength than the piece of high curing temperature.

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An Experimental Study on the Characteristics of Strength in Mortar under High Temperature conditions in an Early Age (모르터 압축강도 특성에 영향을 미치는 고온이력에 관한 실험적 연구)

  • Kim Young Joo;Gong Min Ho;Song In Myung;Yang Dong Il;Paik Min Su;Jung Sang Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.703-706
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    • 2004
  • This study is basic experiment for estimating influence of strength by curing temperature of concrete's heat of hydration and estimate relationship of compressive strength development by initial curing temperature factor, and then asume temperature factor which influence compressive strength development and for showing basic document of quality control. According to the result of cement mortar by the curing temperature factor high-curing temperature shows high strength on 3 day compare with low curing-temperature, shows higher strength than the piece of high curing temperature.

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The Study on the Strength Properties of High Volume Fly-Ash Concrete (플라이애시를 다량 사용한 콘크리트의 강도특성에 관한 연구)

  • Paik, Min-Su;Lee, Young-Do;Jung, Sang-Jin
    • Journal of the Korea Institute of Building Construction
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    • v.2 no.4
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    • pp.169-176
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    • 2002
  • To study of binder and fine aggregate a lot of replacement fly-ash concrete, initial characteristics, standard environment of curing temperature $20^{\circ}C$, hot-weather environment, cold weather environment of curing temperature $5^{\circ}C$. Flash concrete tested slump, air contest, setting and Hardening concrete valuated setting period of form, day of age 3, 7, 28 compression strength in sealing curing. Underwater curing specimen compression strength of age 3. 7, 28day used strength change accordingly fly-ash concrete curing temperature. Purpose of study is consultation materials in field that variety of fly-ash replacement concrete mix proportion comparison and valuation. (1) Setting test result, fly-ash ratio of replacement higher delay totting time. Same volume of fly-ash ratio of replacement is lower fly-ash ratio of replacement fine aggregate delay setting time. Setting test in curing temperature $35^{\circ}C$ over twice fast setting in curing temperature $20^{\circ}C$ and all specimen setting delay in curing temperature $5^{\circ}C$. F40 specimen end of setting about 30 time. (2) Experiment result age 28day compression strength more fisher plan concrete then standard environment in curing temperature $20^{\circ}C$, cold weather environment in curing temperature $5^{\circ}C$, most strength F43 is hot-weather environment in curing temperature $35^{\circ}C$ replacement binder 25%, fine aggregate 15%. (3) Hot-weather environment replacement a mount of fly-ash is a same of plan concrete setting period of form. Age 28day compression strength replacement a mount of fly-ash more hot-weather concrete then plan concrete.

Temperature History of Concrete at Cold Weather Depending on the Kinds of Insulating Sheet (단열양생시트 종류 변화에 따른 한중콘크리트의 온도이력)

  • Jeon, Chung-Keun;Kim, Jong;Shin, Dong-An;Oh, Seon-Kyo;Han, Cheon-Goo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.05a
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    • pp.618-621
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    • 2006
  • This paper is to investigate temperature history of cold weather concrete depending on insulation curing sheet kinds. Insulating effect according to curing sheet is shown in order of 5 layer bubble sheet, combination of PE form and 3 layer bubble sheet and 3 layer bubble sheet. It maintained above $10^{\circ}C$ of minimum temperature until the completion of initial curing period when bubble curing sheet was supplied regardless of curing sheet kinds. Five layer bubble curing sheet secure higher curing temperature than any other curing sheet applied in this experiment by as much as $2{\sim}3^{\circ}C$, which performed remarkable insulation effect. Concrete applied with curing sheet secured above $65^{\circ}D{\cdot}D$ of maturity, at which concrete had 5MPa of compressive strength at 3 days.

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Strength Properties of the Mortar According to the Curing Condition of the Modified Sulfur Mortar (개질유황 모르타르의 양생조건에 따른 모르타르의 강도특성)

  • Jung, Byeong-Yeol;Lee, Sang-Soo;Song, Ha-Young
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2013.05a
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    • pp.332-333
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    • 2013
  • This research utilizes the modified sulfur having the low melting point which 65℃ is tries to study the strength property of the mortar according to the cure method of the modified sulfur mortar. And we try to use as basic data for investigating the curing condition of the light panel optimum utilizing the modified sulfur. We experimented by five kinds; 20℃ water curing method and 20, 40, 60, 80(℃) air dry curing method. In 3 day curing, the compressive strength was improved caused by high curing temperature. But the compressive strength was degraded caused by enhanced temperature in 7day curing and 28day curing. Therefore, the curing temperature of the modified sulfur mortar is determined that it comes 20 time case curing and the water curing is the most recommendable.

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A Study on the Effect of Curing Temperature on the Unconfined Compressive Strength of Soil Cement Mixtures. (양생온도가 Soil Cement의 압축강도에 미치는 영향에 관한 연구)

  • 김재영
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.17 no.4
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    • pp.3931-3942
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    • 1975
  • This study was conducted to investigate the strength of soil cement for varied curing temperatures (0,10,20,30,40,50,60$^{\circ}C$) and cement content (3,6,9,12%) in four cement-stabilized soils (KY: sand, MH: sand, SS: sandy loam, JJ:loam). The experimental results obtained from unconfined compressive strength tests were as follows: 1. According to increase of curing temperature as 30,40,50, and 60$^{\circ}C$, the unconfiened compressive strength of soil cement increased, the rate of increase in the early curing period was large, and around 120 hours was suifficient curing time to complete hardening. 2. The strength at 10$^{\circ}C$ decreased to the rate of 30 to 40 percent than that of 20$^{\circ}C$ while the strength at 0$^{\circ}C$ was very small, strength of soil cement increased in cold weather unless that the temperature was below 0$^{\circ}C$ 3. The average maximum temperature, about 30$^{\circ}C$ during July and August in Korea may be recommended for a optimum construction period to increase the strength of soil cement. 4. Accelerated curing time that strength was equivalent to 28-Day norma1 curing decreased in accordance with the increase of curing temperature, and also accelerated curing decreased the effect of cement content. Accelerated curing that strength was equivalent to 28-day normal curing for soil cement of cement content 9% and temperature 60$^{\circ}C$ was 45 hours; KY, 50 hours: MH, 40 hours; SS, 34 hours; JJ. 5. According to the increase of the percent passing of No. 200 sieve, accelerated curing times became shorter to become the required stength. 6. Relation between accelerated curing times and normal curing days was showeda linear of which slope decreased in accordance with the increase of curing temperature, it may be expressed as follows: (1). 30$^{\circ}C$ t=3.6d+6(r=0.97) (2). 40$^{\circ}C$ t=3.2d-5.1(r=0.95) (3). 50$^{\circ}C$ t=2.1d-4.0(r=0.93) (4). 60$^{\circ}C$ t=1.4d+4.0(r=0.90) in which t=accelerate curing time. d=normal curing day. 7. Accelerated curing time that the strength was equivalent to 35kg/$\textrm{cm}^2$ which was the strength of cement brick was 96 hours at temperature 30$^{\circ}C$ to SS 9%, and 120 hours at temperature 50$^{\circ}C$ to JJ 9%, Consequently, a economic soil cement brick may be made in future.

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Investigated properties of Low temperature curing Ag Paste for Silicon Hetero-junction Solar Cell

  • Oh, Donghyun;Jeon, Minhan;Kang, Jiwoon;Shim, Gyeongbae;Park, Cheolmin;Lee, Youngseok;Kim, Hyunhoo;Yi, Junsin
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.160-160
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    • 2016
  • In this study, we applied the low temperature curing Ag paste to replace PVD System. The electrode formation of low temperature curing Ag paste for silicon Hetero-junction solar cells is important for improving device characteristics such as adhesion, contact resistance, fill factor and conversion efficiency. The low temperature curing Ag paste is composed various additives such as solvent, various organic materials, polymer, and binder. it depends on the curing temperature conditions. The adhesion of the low temperature curing Ag paste was decided by scratch test. The specific contact resistance was measured using the transmission line method. All of the Ag electrodes were experimented at various curing temperatures within the temperature range of $160^{\circ}C-240^{\circ}C$, at $20^{\circ}C$ intervals. The curing time was also changed by varying the conditions of 10-50min. In the optimum curing temperature $200^{\circ}C$ and for 20 min, the measured contact resistance is $19.61m{\Omega}cm^2$. Over temperature $240^{\circ}C$, confirmed bad contact characteristic. We obtained photovoltaic parameter of the industrial size such as Fill Factor (FF), current density (Jsc), open-circuit voltage (Voc) and convert efficiency of up to 76.2%, 38.1 mA/cm2, 646 mV and 18.3%, respectively.

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Properties of Light Weight Foamed Concrete According to Curing Condition (양생조건에 따른 경량기포콘크리트의 특성)

  • Shin, Sang-Chul;Choi, Ji-Ho;Hong, Sung-Rog;Kim, Ji-Ho;Jeong, Ji-Yong;Kim, Jin-Man
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2011.11a
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    • pp.237-239
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    • 2011
  • This study was performed to investigate the influence of curing temperature on the properties of light weight foamed concrete, manufactured on-site construction according to the various experimental factor such as temperature of material, curing temperature in air(5, 10, 20℃), curing time in air(5, 10, 15hour), and target density of hardened state(0.8, 1.2t/㎥). As a result, the influence of the curing temperature on various properties of foamed concrete is greater than curing time. When increasing temperature and time in air curing, progress of hydration is fast and compressive strength is increasing more and more. However, when considering the productivity, minimum curing time is required 15hours at 5℃, 10hours at 10℃, and 5hours at 20℃. If this condition is not required, there is some crack due to volume expansion on the surface of light weight foamed concrete.

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Fast Switching of Vertically Aligned Liquid Crystals by Low-Temperature Curing of the Polymer Structure

  • Park, Byung Wok;Oh, Seung-Won;Kim, Jung-Wook;Yoon, Tae-Hoon
    • Journal of the Optical Society of Korea
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    • v.18 no.4
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    • pp.395-400
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    • 2014
  • We proposed a method for fast turn-off switching of a vertically-aligned liquid crystal cell by low-temperature curing of the polymer structure. We confirmed that the turn-off times of the fabricated cells were reduced significantly as the curing temperature was lowered to $-20^{\circ}C$. We accounted for the effect of low-temperature curing on the turn-off time by using a mathematical model and by observing images obtained via scanning electron microscopy. We also confirmed that low-temperature curing is more effective in reducing the response time when the device is operated at a low temperature.

Study on Initial Scattering State as a Function of Curing Temperature for Polymer Dispersed Liquid Crystal Cells with Different Mixing Ratio (고분자 분산형 액정 셀에서 혼합물의 비율에 따라 노광 온도가 초기 산란도에 미치는 영향)

  • 김미숙;서영현;이명훈;이종문;이택수;이승희
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.1
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    • pp.59-64
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    • 2004
  • We have fabricated the polymer dispersed liquid crystal (PDLC) cell where a control of phase separation is very important. The factors to influence the phase separation are mixing ratio of LC and polymer, curing temperature and UV intensity. In this paper, we inspected the change of a phase separation as a function of curing temperature for the mixture of E7 and. NOA65 with different ratios. When the LC concentration is less than polymer such as LC:NOA65 = 40:60wt%, the PDLC cell is influenced strongly by the curing temperature. However, when the LC concentration is much less than polymer such as LC:NOA65 = 80:20wt%, it is influenced slightly by the curing temperature. The reason is because the mixture shows upper critical solution temperature behavior and therefore it is important to know the behavior of phase separation as a function of curing temperature of the mixture.