• Title/Summary/Keyword: 저발열배합

Search Result 22, Processing Time 0.031 seconds

Fundamental characteristics of high early strength low heat concrete according to mineral binder and high early strength material combination (광물질 결합재 및 조강형 재료 조합에 따른 조강형 저발열 콘크리트의 기초적 특성)

  • Kim, Kyoungmin;Son, Hojung
    • Journal of the Korean Crystal Growth and Crystal Technology
    • /
    • v.24 no.1
    • /
    • pp.27-32
    • /
    • 2014
  • This study analyzed the fundamental characteristics of concrete according to a ternary system mixing in order to reduce hydration heat of mass concrete and to improve early age strength. The results are as follows. The fluidity of unconsolidated concrete satisfied the target scope regardless of the binder conditions. When the replacement ratio between FA and BS increased, the slump of low heat-A mix and low heat-B mix increased, and air content was not affected by the change of binders. As for setting time, low heat cement mix had the fastest regardless of W/B, and high early strength low heat mix achieved 6 hours' reduction compared with low heat-B mix at initial set, and 12 hours' reduction at the final set respectively. As for the simple hydration heat, the low mix peak temperature was the highest and low heat-B mix had the lowest temperature. And high early strength low heat mix was similar with that of low heat-B. The compressive strength of hardened concrete had similar strength scope in all mixes except for low heat-B mix at early ages, and had unexceptionally similar one without huge differences at long-term ages.

Hydration Heat Analysis of Mass Concrete considering Heat Transfer Coefficient and Hydration Heat Difference (수화발열량차 및 열전달계수 변화를 고려한 매스콘크리트의 수화열 해석)

  • Han, Seung-Baek;Lee, Seong-Su;Shin, Hyo-Bum;Kim, Ho-Soo
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2008.11a
    • /
    • pp.249-252
    • /
    • 2008
  • In recent large-scale structures, as mass concrete type structure is frequently applied to the building, temperature crack due to hydration heat needs to be considered. Since a volume change is internally or externally restricted in a mold after placing concrete, temperature crack of mass concrete takes place. By this reason, the reduction method to control this crack is required. In this study, low heat mixture and hydration heat difference is used to execute the analysis of hydration heat, considering the changes of heat transfer coefficient according to curing conditions and block placement of mass concrete. For the analytical modelling, original portland cement and concrete of low heat mixture are placed in the upper and lower payer, respectively. A convection boundary condition is fixed because mass concrete of block placement is characterized by the difference of mold form and curing condition. Through the analysis results considering the changes of low heat mixture, block placement, and heat transfer coefficient, we check out the temperature and stress distribution and analyze the temperature crack reduction effect.

  • PDF

Temperature Control of Mass Concrete with low heat concrete mixtures (저발열 콘크리트 배합에 따른 매스콘크리트 온도 제어)

  • Park, Chan-Kyu;Jang, Jeong-Gi;Jeong, Jae-Hong;Lee, Seung-Hoon;Kim, Seong-Su
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2008.11a
    • /
    • pp.505-508
    • /
    • 2008
  • In this study, temperature increase and strength development of concretes with different types of cement were investigated to construct dam drop spillway. For this purpose, boxes of 1${\times}$1${\times}$1m size with 4 different concrete mixtures were made. The types of concrete were Type I cement concrete, fly ash cement concrete and two type concrete with ternary cement, respectively. The temperature at each point were monitored in these boxes. Based on the Box test, hydration analysis of slab of 2.0m thickness was carried out. This paper presents these experimental and analytical results.

  • PDF

Consideration on the Application of Low-Heat Concrete with Ferronickel Slag Aggregate to LNG Storage Tank (페로니켈슬래그 골재를 활용한 저발열 콘크리트의 LNG 저장탱크 적용성 검토)

  • Sang Hyeon Cheong;Sukhoon Pyo;Hyeong-Ki Kim
    • Journal of the Korean Recycled Construction Resources Institute
    • /
    • v.12 no.1
    • /
    • pp.17-24
    • /
    • 2024
  • The characteristics of low-heat concrete, mixed with ground blast furnace slag and ferronickel slag aggregate, were analyzed. Moreover, the applicability of this concrete for mass concrete in LNG storage tanks was examined. Initially, the study investigated the characteristics of fresh and hardened concrete. Subsequently, the temperature rising curve was obtained. Utilizing the obtained parameters from the curves, a series of thermal stress analyses for the LNG storage tank were conducted to assess the risk of cracking. The results confirmed that concrete mixtures incorporating ground blast furnace slag and ferronickel slag aggregate not only exhibited sufficient workability but also achieved a compressive strength of approximately 40 MPa within 28 days. Furthermore, the concrete demonstrated a lower terminal heat rise and a faster heat generation rate compared to low-heat Portland cement concrete. An analysis of thermal stress in various sections of the LNG tank validated a low risk of cracking.

Hydration Properties of Low Carbon type Low Heat Blended Cement (무기질 자극제를 사용한 탄소배출 저감형 저발열형 혼합시멘트의 수화특성에 관한 연구)

  • Choi, Sung-Woo;Ryu, Deuk-Hyun;Kim, Hun-Sang;Kim, Gyu-Yong
    • Journal of the Korea Institute of Building Construction
    • /
    • v.13 no.3
    • /
    • pp.218-226
    • /
    • 2013
  • Of construction materials, cement and steel are the representative material that carbon dioxide. to reduce carbon emissions in the use of these materials The purpose of this study is low heat type blended cement, which is manufactured using a amount of cement than ordinary low heat blended cement. Low heat blended cement, mixing ratio of 10%, was investigated hydration properties and adiabatic temperature of concrete. The study in order to activate the reaction mineral admixture, a separate source of CaO and $SO_3$ areneeded. gypsum and lime, it expected amount of cement, low-carbon low-heat blended cement could reduce the hydration heat concrete than currentlyused low heat blended cement.

Zero-Crack Construction on the Fundamental Mass Concrete Using Double Bubble Sheets and Applying Low Heat Mixture (저발열 배합 및 이중버블시트에 의한 기초 매트 매스 콘크리트의 무균열 시공)

  • Park, Yong-Kyu;Song, Sung-Bin;Baek, Byung-Hoon;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2006.11a
    • /
    • pp.5-8
    • /
    • 2006
  • This study investigates the field application, Songdo the # 1st WORLD, on zero-crack construction of the fundamental mass concrete using double bubble sheets and applying low heat mixture. Experimental results of hydration heat analysis showed that crack modulus of concrete incorporating 20% of blast furnace slag cement was 1.0 in 120 hours, representing 50% probability of crack occurrence, thus requiring additional measures. As for a curing method, a specimen insulating two layers of vinyl chloride+double bubble sheets exhibited only $16.5^{\circ}C$ difference between upper and lower sections, and it also showed favorable workability as well as competitive economic side. Therefore it was determined to use it for curing method in this field. For the curing results of practical field, using 2 layers of vinyl chloride+double bubble sheets and applying low heat mixture on the fundamental mass concrete in 3A residential building exhibited less than only $15^{\circ}C$ difference between surface and center section of that in 5 days elapse and less than $20^{\circ}C$ in 9 days. This means that the crack by hydration heat was prevented, and other fields structures also resisted the plastic shrinkage by insulating the vinyl, sinking crack by second temping, even drying shrinkage by the mixture of low unit water. Therefore the crack on the placement has not been found so far, since the construction was started before 6 month.

  • PDF

Study on Hydration Heat and Contact the Mix-Design of Foundation Mass Concrete Using Hydration Temperature Analysis Program (수화열 해석프로그램을 이용한 기초 매스콘크리트의 사전 배합선정 및 수화열 검토)

  • Seol, Jun-Hwan;Jo, Man-Ki;Bang, Hong-Soon;Kim, Ok-Kyue
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2019.05a
    • /
    • pp.105-106
    • /
    • 2019
  • In this research, considering the practical conditions at field, thermal cracking method was suggested based on the comparative analysis between predicted value and actual value obtained from the actual structure member with optimum mix design. The optimum mix design was deduced from the various mix designs with various proportions of cementitious binder for upper and lower placement lifts of mat-foundation mass concrete. Therefore, it can be stated that applying low heat mix design and different heating technique between upper and lower placement lifts for mass concrete are efficient to control the thermal cracking. As future issues, based on the interpretation result value, we will select the optimal combination that is applied specifically to the actual site, and deeply analyze the correlation between the measured value and the analysis value through the combination and the test of the actual structure.

  • PDF

Cast in Place of the Low Heat.Self Consolidation Concrete on Underground RC Box Structure using Low Heat Portland Cement (저열 포틀랜드 시멘트를 활용한 일반강도 저발열.자기충전 콘크리트의 지하박스 구조물 현장적용에 관한 연구)

  • Ha, Jae-Dam;Kwon, Tae-Hoon;Yoo, Sung-Young;Kim, Young-Woo;Kwon, Tae-Moon;Ahn, Byung-Rak
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2009.05a
    • /
    • pp.215-216
    • /
    • 2009
  • Recently, the application of SCC (Self Consolidation Concrete) gets more necessity, in order to solve the problem of quality control, noise, etc. In this study describe the optimum mix proportion and the experience of cast in place of the SCC in main structure of underground RC box.

  • PDF

Development and Application of Unit Table Form using Euro Form for High-rise Building Construction (저발열 배합 및 수화발열량차 공법을 이용한 매스콘크리트의 온도제어 및 수화열해석)

  • Jo, Man-Ki;Kim, Min-Ho;Jang, Duk-Bae;Yang, Seong-Hwan;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2015.05a
    • /
    • pp.25-26
    • /
    • 2015
  • In this study, we test the 3 properties low hydrated heat as binder, and also utilized the hydrated heat disparity construction method to decrease the cracks of the mass concrete caused by hydrated heat. The result showed by using the two methods narrowly decreased the cracks. And we ensured that during the mass concrete pouring, the cracks caused by hydrated heat could be reduced by utilizing the new construction method.

  • PDF

The research about properties of modified low heat slag cement (개질 처리된 저발열 슬래그시멘트 특성에 관한 연구)

  • Kim, Hong-Joo;Kim, Won-Ki;Kim, Hoon-Sang;Lee, Won-Jun;Shin, Jin-Ho
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2008.04a
    • /
    • pp.677-680
    • /
    • 2008
  • The surface of particles was energetically modified by inter-grinding OPC and BFS in vibration mill for improvement of the early strength and low-heat evolution of concretes. BFS was pre-grinding in ball-mill to 2535(BS2) and 3245 $cm^2/g$(BS3), in blaine surface area. The inter-grinding time in vibration mill was changed from 10 minutes to 30 minutes. And Mixing ration of BFS to OPC was changed in 60, 70, 80%. After inter-grinding, the change of specific surface area, particle size distribution, hydration heat of cement and compressive strength of mortar were measured. As the result of comparison test with LHC, it was found that the mixture and inter-grinding time satisfying the value of over 100% of compressive strength for 7 days and under 170J/g of heat of hydration for 72 hours. and it was confirmed that the possibility of low heat slag cement utilizing blast furnace slag(BS2, BS3) with the low fineness in high volumes.

  • PDF