• 제목/요약/키워드: Strength Development

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등가재령방법에 의한 혼화재 종류별 콘크리트의 압축강도 증진해석 (Estimation of the Compressive Strength of the Concrete incorporating Mineral Admixture based on the Equivalent Age Method)

  • 한민철;한천구
    • 한국건축시공학회지
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    • 제7권1호
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    • pp.71-77
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    • 2007
  • This paper is to investigate the effect of the curing temperature on strength development of concrete incorporating cement kiln dust(CKD) and blast furnace slag (BS) quantitatively. Estimation of the compressive strength of the concrete was conducted using the equivalent age equation and the rate constant model proposed by Carino. Correction of Carino model was studied to secure the accuracy of strength development estimation by introducing correction factors regarding rate constant and age. An increasing curing temperature results in an increase in strength at early age, but with the elapse of age, strength development at high curing temperature decreases compared with that at low curing temperature. Especially, the use of BS has a remarkable strength development at early age and even at later age, high strength is maintained due to accelerated pozzolanic activity resulting from high temperature. Whereas, at low curing temperature, the use of BS leads to a decrease in compressive strength. Accordingly, much attention should be paid to prevent strength loss at low temperature. Based on the strength development estimation using equivalent age equation, good agreements between measured strength and calculated strength are obtained.

저열 포틀랜드 시멘트 콘크리트의 고강도 영역에서의 강도발현 특성 (Strength Development of Low Heat Portland Cement Concrete in High Strength Range)

  • 하재담;엄태선;이종열;권영호
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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    • pp.353-356
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    • 2005
  • Strength development of low heat portland cement(Type IV) concrete in high strength range is tested. In this study strength development according to water-binder ratio, strength development according to age, effect of fly ash and super plasticizer are tested. This study tests effect of low heat portland cement in high strength range concrete and provide guide line concrete mix design for later study and/or construction.

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석탄재가 혼입된 콘크리트 강도발현에 관한 연구 (An Experimental Study on Strength Development of Concrete Including Fly Ash)

  • 배성용
    • 한국해양공학회지
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    • 제14권3호
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    • pp.66-71
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    • 2000
  • The main objectives of this study are to carried out in order to evaluate strength development of Fly Ash concrete containing various amounts of Fly Ash such as 0%, 10%, 20% and 30%. The experimental variables included in this test program consist of content of Fly Ash, concrete strength and chemical activation. As Fly Ash increases, air content, strength development of concrete and slump loss of normal strength concrete were gradually decreased. The inclusion of Na$_2$SO$_4$increased the short-term strength of concrete that contains Fly Ash. In addition, the strength development of concrete that contains Fly Ash and Na$_2$SO$_4$were improved.

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조기강도 개선형 시멘트를 사용한 콘크리트의 조기강도 발현 특성 (Early Strength Development Properties of Concrete using Early Strength Improvement Type Cement)

  • 박규연;김용로;김규용
    • 한국건축시공학회지
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    • 제13권3호
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    • pp.227-234
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    • 2013
  • 본 연구에서는 3종 조강시멘트에 비해 경제성을 개선하고, 1종 보통포틀랜드시멘트에 비해 조강성능을 개선한 조기강도 개선형 시멘트를 사용한 조강콘크리트의 양생온도 및 물시멘트비에 따른 굳지 않은 콘크리트 특성 및 조기강도 발현 특성을 검토함으로써, 이를 활용한 조강콘크리트의 실용화를 위한 기초자료를 제시하고자 하였다.

마이크로파를 이용한 콘크리트 강도추정에 관한 연구 (A Study on the Strength Estimation of Concrete Using Microwave)

  • 박일용;이종균;박영진;안형준;정상진
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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    • pp.219-222
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    • 1999
  • Concrete is to be important quality in placement point and exact test method needed about early judgement method concrete on placement point. But early judgement method of concrete proposed various kind of method because the problems of accuracy and the time required of test exists, it is used within the limits. This study is to propose of early strength judgement by using microwave for accurate estimating early strength of concrete and to develop test machine. Through out this study we find that belows. 1) Strength development of concrete specimen according to the time heated by microwave showed the height strength development in 9 minutes regardless of slump and w/c. 2) As cooling time is long, strength of concrete specimen according to the time heated by microwave showed high strength development and this tendency is like regardless of heating time, w/c and slump. 3) As w/c is high, accelerating strength development according to w/c showed lower strength development and this tendency is like regardless of slump, heating time and cooling time. 4) As slump is big, compressive strength of specimen in standard curing showed lower value and as w/c is big, strength development showed lower

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혼화재 치환 콘크리트의 압축강도 증진해석 (Estimation of Compressive Strength of Concrete Incorporating Admixture)

  • 주은희;배장춘;한민철;손명수;전현규;한천구
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2005년도 추계 학술논문 발표대회
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    • pp.75-78
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    • 2005
  • This raper investigates the effect of curing temperature on strength development of concrete incorporating cement kiln dust(CKD) and blast furnace slag (BS) quantitatively. Estimation of compressive strength of concrete was conducted using equivalent age equation and rate constant model. An increasing curing temperature results in an increase in strength at early age, but with the elapse of age, strength development at high curing temperature decreases compared with that at low curing temperature. Especially, the use of 35 has a remarkable strength development at early age and even at later age, high strength is maintained due to accelerated pozzolanic activity resulting from high temperature. Whereas, at low curing temperature, the use of BS leads to a decrease in compressive strength. Accordingly, much attention should be paid to prevent strength loss at low temperature. Based on the strength development estimation using equivalent age equation, good agreements between measured strength and calculated strength are obtained.

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플라이애쉬 혼입량 및 양생방법이 콘크리트의 강도발현에 미치는 영향 (The Effect of Flyash Content and Curing Condition on Strength Development of Flyash Concrete)

  • 이진용;배성용
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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    • pp.118-123
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    • 1997
  • The strength development of Flyash concrete containing various amount of Flyash (0, 10, 30, 50%) using as a cement replacement material was investigated two types of curing conditions, namely water curing at $21^{\cire}C$ and steam curing at $25^{\cire}C$ were adopted for this work, in water curing the strength development of Flyash concrete was always inferior to that of OPC (Ordinary Portland Cement) concrete at early ages, although the differences were dependant up percentage of Flyash. The strength of Flyash concrete based on equivalent strength development at 28 days was also tested and the results exhibited that the strength was improved at early days, specially, the concrete containing 30% of Flyash, in steam curing for the same mix(270kg/$\textrm{cm}^2$) the strength of Flyash concrete similar to that of OPC concrete, in other words. Flyash was strongly influenced by curing temperature in the strength development.

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혼화재 종류 변화에 따른 저온조건하 콘크리트의 초기강도 발현 특성 (Strength Development of the Concrete at Early Age subjected to Low Temperature depending on Admixture Types)

  • 한민철
    • 한국건축시공학회지
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    • 제7권4호
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    • pp.145-151
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    • 2007
  • In this paper, tests are carried out in order to investigate the strength development of concrete under various binder types, W/B and curing temperature ranged from $5{\sim}20^{\circ}C$. Fly ash and blast furnace slag were incorporated by as much as 30%, respectively. Strength development of concrete are estimated using Logistic model and strength ratio of concrete at 28days to that at early age are also investigated. According to experimental results, it is found that good agreements are obtained between measured values and calculated ones using logistic model below $20^{\circ}C$. Strength ratio of concrete at 28days to that at early age increases in case W/B decreases and curing temperature increases. Tables and graphs for strength ratio of concrete are provided in this paper. It is capable of obtaining and predicting the periods to attain design strength by considering increment factor of strength easily with the table and graphs presented in this paper. This paper presents the reference data to decide removal time of form, time to reach target strength and strength inspection of remicon whether the test specimens meet the specified criteria of compressive strength. Multi regression models with respect to the relationship between 7days compressive strength and 28 days compressive strength depending on W/B and admixture types are presented.

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

  • 권희성;최응규;임남기;이영도;정상진
    • 한국건축시공학회지
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    • 제8권4호
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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.

슬립폼 적용을 위한 고강도콘크리트의 조기강도 발현성상에 관한 실험적 연구 (An Experimental Study on Early Strength Development of High-Strength Concrete to Apply Slip-Form)

  • 주지현;여동구;강석표;길배수;남재현;김무한
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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    • pp.355-358
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    • 2000
  • Nowadays, with high-storied and large-sized of structures, high-strength concrete is applied to the various kinds of concrete structure. Among of them, for reduction of completion time, high-strength concrete is applied to the high-storied tower, building which is constructed continuously by the slip-form method and it is expected to be on the increase. In this case, it is very important to grasp development of early-strength to apply the slip-form method. But the strength data prior 1 day is rare. Therefore, to apply slip-form method in field, this study aim is to present basic data for development of early-strength of high-strength concrete, through examining development of strength by different curing temperature, replacement of fly-ash.

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