• Title, Summary, Keyword: Curing temperature

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A Study on Development of Curing Apparatus for In-place Standard Curing Specimen (현장 표준양생 공시체 관리함의 개발에 관한 연구)

  • 김경민;전충근;손성운;김기철;한천구
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.97-100
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    • 2004
  • In-place curing box for specimens is used to cure the compressive strength specimens for control in place concrete. The box if composed of insulating chamber maintaining 20$\pm$3$^{\circ}C$ of temperature, in this paper, strength and temperature history of specimens cured at in plate curing box are investigated to verify field applicability. According to test results, air temperature at measured time shows large temperature variation and below zero, whereas, inside temperature of in place curing box maintains within 20$\pm$3$^{\circ}C$ due to temperature control function. For curing condition. temperature of specimens cured at outside shows large temperature deviation. specimens lured at in-place curing box is not affected by outer temperature.

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An Effects of the Strength Development of High Strength Mortar under Temperature History by Steam Curing (촉진양생에 의한 온도이력이 고강도 모르타르의 강도발현에 미치는 영향)

  • Kwon, Hee-Sung;Choi, Eung-Kyu;Lim, Nam-Ki;Lee, Young-Do;Jung, Sang-Jin
    • Journal of the Korea Institute of Building Construction
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    • v.8 no.4
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    • pp.115-121
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    • 2008
  • The present study performed low-pressure steam curing with mortar specimens in order to examine the temperature profile and strength development of steam curing in high-strength specimens of 100MPa. In addition, as a basic research to utilize PC products, we examined the effects of curing temperature and time in steam curing cycle on strength development resulting from the hydration of cement within the range of high strength by changing four factors affecting the quality of PC displacement time, peak curing temperature, peak temperature duration, and ascending and descending gradient of temperature - in various patterns, and analyzed the optimal strength development characteristic based on the relation between temperature profile and strength development. With regard to the high-temperature curing characteristic of PC, we performed an experiment on the strength characteristic according to the temperature profile of high-strength mortar, and from the results of the experiment according to curing characteristic, displacement time, peak curing temperature, peak temperature duration, and ascending and descending gradient of temperature, we drew conclusions as follows.

An Experimental Study on the Characteristics of Compressive Strength in Cement Mortar under High Temperature conditions in an Early Age (초기 고온이력이 시멘트 모르터의 강도발현에 미치는 영향에 관한 연구)

  • Kim Young-Joo;Choi Maeng-Ki;Gong Min-Ho;Park Hee-Gon;Kim Kwang-Ki;Jung Sang-Jin
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.45-48
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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 qualify 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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A Study on the Effects of Curing Temperature for Compressive Strength of High Performance Concrete (양생온도 변화가 고성능 콘크리트의 압축강도에 미치는 영향에 관한 연구)

  • Ro, In-Cheul
    • Journal of the Korea Institute of Building Construction
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    • v.2 no.4
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    • pp.163-168
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    • 2002
  • The object of this study is to define the characteristics of high performance concrete with varing compressive strength of concrete and curing temperature. The major test variables are 1) high strength concrete(500kg/$cm^2$) and ordinary strength concrete(240kg/$cm^2$) compressive strength, 2) curing temperature and condition, 3) concrete curing age, 4) three types of cement. From the test results were shown that curing temperature and curing conditions were also very effective for high strength concrete and ordinary strength concrete, and concrete were largely effected by cement type and temperature during the hydration reaction process. This paper describes the effect of curing temperature for strength and characteristics of high performance concrete.

Effects of Re-vibration and Curing Temperature on the Physical Properties of Latex-Modified Concrete (진동가력과 양생온도가 라텍스개질 콘크리트에 미치는 영향)

  • 정원경;홍창우;이주형;윤경구
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.799-804
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    • 2003
  • The purpose of this study was to investigate the effects of re-vibration and curing temperature onto the physical properties of latex-modified concrete with ordinary cement and rapid-setting cement, and thus to provide a guide line of re-vibration and curing conditions for good quality controls. The main experimental variables included two cement types(ordinary portland cement, rapid-setting cement), curing Temperature($10^{\circ}C$, $20^{\circ}C$, $30^{\circ}C$), re-vibration methods(continued, intermittent), and re-vibration times(initial setting, one day after mixing). The experimental results showed that the re-vibration affected little to the mechanical properties of LMC and RSLMC, while, the curing temperature a quite some. The early strength development was the highest at $20^{\circ}C$ curing temperature, and decreased at higher temperature. The permeability of concrete generally decreased with curing time. The rapid chloride permeability was a function of time and temperature. The chloride permeability of RSLMC was so small and negligible.

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A Fundamental Study on the Strength Development in Cement Mortar under Initial Curing Temperature (초기양생온도에 따른 시멘트 모르터의 강도발현에 관한 기초적 연구)

  • 백민수;이영도;임남기;김성식;이종균;최문식;정상진
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.157-165
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    • 1997
  • In this experiment, there is a purpose to analysis the relationship of feature of compressive strength after fixing of remarkable element under the condition of initial curing temperature. According to this experiment, we get to the fallow result. In case of highest curing temperature, 3-day-strength become high but last revelation of strength become low among the condition of initial curing temperature, the highest curing temperature have an effect on revelation of strength by the application of cumulative temperature, we can get the shape of revelation of strength.

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Evaluation of early age mechanical properties of concrete in real structure

  • Wang, Jiachun;Yan, Peiyu
    • Computers and Concrete
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    • v.12 no.1
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    • pp.53-64
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    • 2013
  • The curing temperature is known to influence the rate of mechanical properties development of early age concrete. In realistic sites the temperature of concrete is not isothermal $20^{\circ}C$, so the paper measured adiabatic temperature increases of four different concretes to understand heat emission during hydration at early age. The temperature-matching curing schedule in accordance with adiabatic temperature increase is adopted to simulate the situation in real massive concrete. The specimens under temperature-matching curing are subjected to realistic temperature for first few days as well as adiabatic condition. The mechanical properties including compressive strength, splitting strength and modulus of elasticity of concretes cured under both temperature-matching curing and isothermal $20^{\circ}C$ curing are investigated. The results denote that comparing temperature-matching curing with isothermal $20^{\circ}C$ curing, the early age concretes mechanical properties are obviously improved, but the later mechanical properties of concretes with pure Portland and containing silica fume are decreased a little and still increased for concretes containing fly ash and slag. On this basement using an equivalent age approach evaluates mechanical properties of early age concrete in real structures, the model parameters are defined by the compressive strength test, and can predict the compressive strength, splitting strength and elasticity modulus through measuring or calculating by finite element method the concreted temperature at early age, and the method is valid, which is applied in a concrete wall for evaluation of crack risking.

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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    • 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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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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