• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.379-384
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• 2001

This Paper Presents field application test results of mass concrete using super retarding agent. The field test was carried out at mat foundation(thickness 1m) of newly constructed information center of Chongju university. Placing lift composed of 2 layers, and each layer is 50cm. Fly ash and flowing method is also applied. Difference of setting time of concrete between with super retarding agent and without super retarding agent is considered. Concrete without super retarding agent is placed at upper layer and with super retarding agent at lower layer According to test results, the reducing method of hydration heat considering difference of setting time with super retarding agent can reduce the highest temperature about 3~4$^{\circ}C$, and delay the peak time about 3~4days. Compressive strength using super retarding agent is somewhat higher than that of normal concrete. Accordingly, super retarding agent does not affect the strength development.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 가을 학술논문 발표대회
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• pp.127-128
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• 2020

This research is part of the research for unifying the mass concrete and utilizing the rate of super retarding agent. We analyzed the performance of super retarding agent 20℃ conditions. It was found that there was no deterioration in fluidity and air quality due to the change in the super retarding agent mixing rate. It was found that when super retarding agent was mixed up to 0.5 %, it was delayed for 22.3 hours at 20℃. Therefore in order to ensure the performance required at the site, the super retarding agent mixing rate must be determined by fully considering the situation at the site. In addition it will be analyzed that super retarding agent performance analysis at high temperature will be required in subsequent studies.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 가을 학술논문 발표대회
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• pp.10-11
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• 2020

This research is part of the research for unifying the mass concrete and utilizing the rate of super retarding agent. We analyzed the performance of super retarding agent under low temperature conditions. It was found that there was no deterioration in fluidity and air quality due to the change in the super retarding agent mixing rate. It was found that when super retarding agent was mixed up to 0.5 %, it was delayed for 22.3 hours at 20℃, 48.2 hours at 10℃, and 48.5 hours at 5℃. Therefore in order to ensure the performance required at the site, the super retarding agent mixing rate must be determined by fully considering the situation at the site. In addition it will be analyzed that super retarding agent performance analysis at high temperature will be required in subsequent studies.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
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• pp.1195-1198
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• 2000

In this paper, setting and strength properties of concrete with contents of super retarding agent are discussed. Gluconic acid and sucrose and used for super retarding agent. According to experimental results, as super retarding agent content increases, slump show to be increased, while air content decrease about 1~2%. In case of setting properties, as super retarding agent content increases, setting time delays considerable. When gluconic acid and sucrose is added about 0.3%, it delays more than 10days. Compressive strength of concrete of concrete with super retarding agent shows to be higher than that without it. Retarding of setting time of concrete using gluconic acid is longer than that using sucrose.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.131-132
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• 2021

In this study, as part of the study to reduce and integrate heat of hydration of concrete, the performance change of super retarding agent is examined in the mortar area under high temperature conditions. It was confirmed that the setting time delay can be adjusted from several hours to several days depending on the high temperature and the change of super retarding agent mixing rate. With the increase of super retarding agents, the early age strength was delayed while at 28 days the use of super retarding agent results in an increase of strength remakably.

• 한국건축시공학회지
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• 제8권3호
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• pp.111-117
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• 2008

This study provides the setting time prediction method of super retarding concrete incorporating mineral admixtures at the same time including fly ash(FA), blast furnace slag(BS) based on maturity method. The setting time was retarded, as super retarding agent contents increase and curing temperature decreases. In addition, apparent activation energy by Arrhenius function was ranged from $24{\sim}35KJ/mol$ with slightly difference along with mixture proportion. This value is smaller than existing value $30{\sim}50KJ/mol$. It is Indicated that equivalent age using setting time can be a proper method to predict setting time and it also exhibited comparable relativity between prediction value and measurement value. Therefore, this study provided setting time prediction value with super retarding agent contents and mineral admixture combination. Setting time prediction equation provided herein is possibly valid for estimating precise setting time of the super retarding concrete at the job site.

• 한국건축시공학회지
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• 제8권5호
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• pp.119-125
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• 2008

In this paper, the estimation of super retarding concrete incorporating mineral admixtures at the same time including fly ash(FA), blast furnace slag(BS) are studied based on maturity method. The setting time was retarded, as super retarding agent contents increase and curing temperature decreases. In addition, apparent activation energy by Arrhenius function was ranged from $24\sim35$ KJ/mol with slightly difference along with mixture proportion. This value is smaller than existing value $30\sim50$ KJ/mol. Based on strength development estimation. it exhibited comparable relativity between prediction value and measurement value. Therefore, this study provided effective strength development prediction value with super retarding agent contents and mineral admixture combination. Strength development prediction equation provided herein is possibly valid for estimating accurate strength development of the super retarding concrete at the job site.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문발표회
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• pp.95-98
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• 2003

This paper presents the results of field experiment to apply the difference of setting tine method using super retarding agent for reducing hydration heat of mass concrete of foundation. According to the results, as the properties of fresh concrete, base concrete satisfies aimed slump and air content, and there is no difference of slump and air content with mixture of super retarding agent. The mixing ratio of super retarding agent is determined for setting time to be retarded by 12 hours in comparison with base concrete, but because the temperature of the air and concrete is low, the difference of setting time is retarded to 24 hours. In man concrete of foundation to which the difference of setting time method is applied, crack by hydration heat is not seen because the lower concrete of super retarding agent generates heat after generation of hydration heat of the upper concrete.

• 콘크리트학회논문집
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• 제14권4호
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• pp.589-596
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• 2002

본 연구에서는 당분류의 초지연제를 중심으로 굳지 않은 콘크리트의 유동성, 공기량, 응결특성 및 경화 콘크리트의 강도특성을 분석하였다. 실험결과 먼저, 굳지 않은 콘크리트의 슬럼프 값은 초지연제의 혼입률이 증가함에 따라 다소 증가하는 것으로 나타난 반면, 공기량은 감소하는 것으로 나타났다. 응결특성으로는 혼입률이 증가함에 따라 응결시간이 비약적으로 지연되어 혼입률 0.3%에서 글루콘산은 10일 이상, 슈크로스, 백설탕 및 황설탕은 10일 이상에서 종결이 측정되었다. 또한, 종결이후 압축강도는 초지연제 혼입시 초기강도는 플레인에 비해 낮게 측정되었지만 3일 재령 이후에서는 플레인과 동등하거나 그 이상으로 나타났다. 종합적으로 당분류의 백설탕은 가격이 저렴하면서도 응결지연 특성 및 강도특성에서 여타의 초지연제에 비해 커다란 문제점이 없는 것으로 분석되어, 향후 내구성 등 제반특성이 심도 있게 검토된다면 우수한 초지연제로서의 활용가능성을 확인 할 수 있었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.469-474
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• 2001

Mass concrete is placed considering placing lifts 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.