• 제목/요약/키워드: heat of hydration in concrete

검색결과 538건 처리시간 0.035초

고강도 콘크리트의 수화열 저감에 미치는 혼화재 종류 및 대체율의 영향에 관한 연구 (A Study on the Effect of Admixture Types and Replacement Ratio on Hydration Heat Reduction of High-Strength Concrete)

  • 김무한;최세진;오시덕;김용로;이종호
    • 한국건축시공학회지
    • /
    • 제2권2호
    • /
    • pp.145-150
    • /
    • 2002
  • The hydration of cement paste occurs when the cement is miked with water. During the hydration, hydration heat causes the thermal stress depending on the site of concrete and the cement content. Especially in the high-strength concrete, we must give care to the concrete due to its large cement content. In this study conduction calorimeter and concrete insulation hydration heat meter were used to investigation the hydration heat characteristics of cement and concrete. To reduce hydration heat of high-strength concrete, several types of replacement of fly-ash and blast-furnace slag powder were used in this experiment. As a result of this study, it was found that hydration heat of high-strength concrete was reduced by replacement of fly-ash and blast-furnace slag powder. In case of high-strength concrete using blast-furnace slag powder, the max-heat arrival time was delayed but an effect of heat reduction was lower than a case of high-strength concrete using fly-ash, because it was considered that the heat-dependence property of blast-furnace slag powder was higher than that of fly-ash.

분말형 수화열저감재를 사용한 저발열 콘크리트의 수화발열 특성 (The Characteristics of Hydration Heat Generation of Low Heat Concrete using Hydration Heat Reducing Admixtures)

  • 김용로;정양희;이상호;김도수;길배수;김원기
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 2006년도 추계 학술발표회 논문집
    • /
    • pp.709-712
    • /
    • 2006
  • It is necessary to develop a new technology for controling thermal cracking by hydration heat according to the increase construction of massive concrete structures, high strength concrete and early strength concrete. Therefore, it was investigated the characteristics of hydration heat generation of low heat concrete using hydration heat reducing admixtures in this study. To investigate the performance of hydration heat reducing admixtures, it was evaluated hydration heat according to the kind and replacement ratio of phase change material series I, II and the way of using hydration heat reducing admixtures in series III.

  • PDF

결합재 종류에 따른 저발열 콘크리트의 수화발열 특성에 관한 실험적 연구 (An Experimental Study on the Characteristics of Hydration Heat Generation of Low Heat Concrete with Binder Types)

  • 김용로;정양희;이상호;김도수;길배수;한승구
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
    • /
    • pp.417-420
    • /
    • 2006
  • Recently, the attention is paid to the problem of thermal crack by hydration heat according to the increase of high strength and mass concrete structures. At this point, various research has been carried out for the control of hydration heat in high strength and mass concrete. As a part of the research, it was investigated application of hydration heat reduction agent (HR) for the control of thermal crack by hydration heat in this study. To investigate the application, it was selected HR which can reduce hydration heat of concrete with effect in series I and II. Also, it was investigated the characteristics of hydration heat generation of low heat concrete using HR with binder types in seriesIII.

  • PDF

플라이애쉬를 사용한 수중불분리성 콘크리트의 수화열에 관한 연구 (A Study on the Hydration Heat of Antiwashout Underwater Concrete Using Fly Ash)

  • 권중현
    • 한국해양공학회지
    • /
    • 제14권4호
    • /
    • pp.30-34
    • /
    • 2000
  • The concretes cast in the sea water would be likely to be rich mix and mass concrete. Therefore it is important to check out the hydration heat of concrete and to reduce it to prevent the concrete from processing the temperature crack. Recently the antiwashout agent is used on underwater concrete for preventing from the segregation of concrete in the water. The experimental studies were done for the combined cement replaced by fly ash 30%unit weight of binder to study on the characteristics of hydration heat of antiwashout underwater concrete, and its characteristic was discussed by comparing on cast in sea water with anther one in air. The present paper showed that the hydration heat concrete replaced by 30%of fly ash was more significantly reduced than the normal concrete. The hydration heat of antiwashout underwater concrete was highter than that of normal concrete, but it was reduced lower than the normal concrete by adding fly ash.

  • PDF

초지연제의 응결시간차에 따라 분할타설된 매스 콘크리트의 수화열 저감 (Reduction of Hydration Heat in Division-Placed Mass Concrete Considering the Difference of Setting Time in Super Retarding Agents)

  • 지석;배정렬;황인성;윤치환;김기철;한천구
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 2002년도 가을 학술발표회 논문집
    • /
    • pp.805-808
    • /
    • 2002
  • This study is designed to reduction of hydration heat of 4 layer division-placed mass concrete considering the difference of setting time of super retarding agent. According to the results, peak temperature of plain concrete by hydration heat show $63^{\circ}C$ around the age of 1 days. Hydration heat is lowest in the bottom layer, and highest in the middle of 3rd layer from the bottom. Hydration heat of mock up structure, which is division-placed at the same interval of 1 and 2 days by setting time difference of super retarding agent, is highest in the bottom layer because after peak temperature of 4th layer, hydration reaction progresses in order of 3rd, 2nd and 1st layer. But in mock up structure which is division-placed at the various interval. peak temperature by hydration heat is reduced by about $13^{\circ}C$, compared with plain concrete because after first peak hydration heat of 4th layer (plain concrete), hydration reaction progresses after the drop of hydration heat in order of 3rd, 2nd and 1st layer.

  • PDF

혼화재를 사용한 콘크리트의 수화모델 (A Hydration Model for Blended Concrete utilizing Secondary Cementitious Powders)

  • 노재명;변근주;송하원
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
    • /
    • pp.140-143
    • /
    • 2004
  • Heat of hydration of concrete under different curing temperatures can be characterized with knowledge of the thermal activity, the heat rate at the reference temperature, and the total heat of hydration of the mixture. The so-called multi-component hydration model incorporates the effect of following variables: cement chemical composition, cement fineness, secondary cementitious powders, mixture proportions, and concrete properties. However, the model does not consider the use of silica fume as a secondary cementitious powder. Therefore, the model that quantifies the heat of hydration due to the use of silica fume is needed. In this thesis, the effects of silica fume on heat of hydration are evaluated and the influence on the heat of hydration are also quantified to be included in the model, so that the analysis using modified multi-component hydration model for silica fume concrete provides more accurate results than normal concrete.

  • PDF

혼화재 종류 및 대체율에 따른 고강도콘크리트의 수화열 저감 효과 (Reducing effect for Hydration Heat of High-Strength Concrete according to Admixture Types and Replacement Ratios)

  • 유범재;김용로;최세진;김상윤;김상규;김무한
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 2001년도 가을 학술발표회 논문집
    • /
    • pp.409-414
    • /
    • 2001
  • The hydration of cement paste occurs when the cement is mixed with water. During the hydration, hydration heat causes the thermal stress depending on the size of concrete and the cement content. Especially in the high-strength concrete, we must give care to the concrete due to its large cement content. In this study, conduction calorimeter and concrete insulation hydration heat meter were used to investigate the hydration heat characteristics of cement and concrete. To reduce hydration heat of high-strength concrete, several types of replacement of fly-ash and blast-furnace slag powder were used in this experiment.

  • PDF

응결시간차를 활용한 매스콘크리트의 수화열 조정에 관한 기초적 연구 (A Fundamental Study on the Control of Hydration Heat of Mass Concrete Using Setting Time Difference)

  • 배정렬;윤치환;김기철;한민철;오선교;한천구
    • 한국건축시공학회:학술대회논문집
    • /
    • 한국건축시공학회 2002년도 학술논문발표회
    • /
    • pp.41-45
    • /
    • 2002
  • Placing lift is applied to place mass concrete in order to reduce thermal cracks by hydration heat. But they results in cold joint between placing lifts, which bring about the loss of strength, water tightness and undesirable appearance. Therefore, in this paper, mechanical and hydration heat of mass concrete using super retarding agent developed through previous study are investigated in order to reduce the hydration heat and place it without place lift. According to test results, placing lifts combined with normal concrete and concrete containing super retarding agent have positive effects on reducing hydration heat. Especially, the crack index by thermal stress of the concrete containing super retarding agent less than a quarter, compared to that of plain concrete without placing lifts, and less than a half, compared to that of plain concrete with placing lifts.

  • PDF

고강도 매스 콘크리트-보의 수화열 및 강도특성 (Hydration Heat and Strength Properties of Mass Concrete Transfer Girder)

  • 강연우;김규용;김순묵;김수봉;한장훈;정재영
    • 한국건축시공학회:학술대회논문집
    • /
    • 한국건축시공학회 2013년도 추계 학술논문 발표대회
    • /
    • pp.28-29
    • /
    • 2013
  • When concrete was hardened, it should had considered a crack to make internal stress by hydration heat. For control of crack, admixture was use to change cement because hydration heat was effect to cement. High strength mass concrete had much hydration heat with high volume of cement. It was necessary to reduce hydration heat in construction method. In this study, it evaluates hydration heat, compressive strength of transfer concrete girder regard to field construction type such as separation, whole etc. Also, we test compressive strength of concrete with core and mold specimen.

  • PDF

진동형 히트 파이프를 이용한 하계 매스 콘크리트의 수화열 냉각에 관한 실험적 고찰 (An Experimental Study on Cooling of Hydration Heat of Mass Concrete Structure using Pulsating Heat Pipe in Summer Season)

  • 양태진;김정훈;김종수
    • Journal of Advanced Marine Engineering and Technology
    • /
    • 제31권1호
    • /
    • pp.51-57
    • /
    • 2007
  • In process of reinforced concrete (RC) box structure. the heat of hydration may cause serious thermal cracking. In order to eliminate hydration heat of mass concrete. this paper reports results of hydration heat control in mass concrete structure using the pulsating heat pipe. There were three RC box molds($1.2{\times}l.8{\times}2.4m^3$) which shows a difference as compared with each other. One was not equipped with pulsating heat pipe. The others were equipped with pulsating heat pipe. All of them were cooled with natural air convection. The pulsating heat pipe was composed of serpentine type copper pipe with 10 turns (outer diameter: 4mm. inner diameter: 2.8mm). The working fluid was R-22 and its charging ratio was 40% by volume. The conditions such as the number of turns. the length and the pitch of the pulsating heat pipe and the size of concrete structure were changed. Based on these experiments, it was confirmed that this construction method using pulsating heat pipe was effective to remove hydration heat of mass concrete structure and thus it was possible to prevent harmful thermal crack and construction Period and costs of concrete structure would be cut down.