• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.709-712
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• 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.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.417-420
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• 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.

• Computers and Concrete
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• 제9권3호
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• pp.179-193
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• 2012

The hydration of cement contributes to the performance characteristics of concrete, such as strength and durability. In order to improve the utilization efficiency of cement and its early properties, the particle size distribution (PSD) of cement varies considerably, and the effects of the particle size distribution of cement on the hydration process should be considered. In order to evaluate effects of PSD separately, experiments testing the isothermal heat generated during the hydration of cements with different particle size distributions but the same chemical composition have been carried out. The measurable hydration depth for cement hydration was proposed and deduced based on the experimental results, and a PSD hydration model was developed in this paper for simulating the effects of particle size distribution on the hydration process of cement. First, a reference hydration rate was derived from the isothermal heat generated by the hydration of ordinary Portland cement. Then, the model was extended to take into account the effect of water-to-cement ratio, hereinafter which was referred to as PSD hydration model. Finally, the PSD hydration model was applied to simulate experiments measuring the isothermal heat generated by the hydration of cement with different particle size distributions at different water-to-cement ratios. This showed that the PSD hydration model had simulated the effects of particle size distribution and water-to-cement ratio on the hydration process of cement with satisfactory accuracy.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 가을 학술논문 발표대회
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• pp.129-130
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• 2020

This paper attempted to examine the characteristics of heat of hydration and calorific value of concrete according to the formwork material in Hot weather environment. As a result of the experiment, it was found that there were no problems such as temperature cracking and delay in hydration reaction when a synthetic resin form was used.

• 한국세라믹학회지
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• 제27권4호
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• pp.560-566
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• 1990

The early hydration characteristics according to the C3A polymorphism and the presence of gypsum, in order to establish the hydration mechanism of the system C3S-C3A, have been studied. The hydration rate of C3A was changed according to the its crystal structure and influenced the hydration of C3S. That is, the hydration rate of C3S was accelerated in case of orthorhombic-C3A, but that was slightly retarded in case of melt-C3A than that of cubic-C3A. In the system C3S-C3A-gypsum, the retardation phenomenon of the reaction of monosulfate formation was observed in case of both orthorhombic and melt-C3A.

• 한국세라믹학회지
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• 제26권4호
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• pp.514-520
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• 1989

The early hydration characteristics according to the C3S/C3A ratio and presence of gypsum, in order to establish the hydration mechanism of the system C3S-C3A, have been studied. The rate of C3S dissolution in the system C3S-Gypsum was higher than that in the system C3S. Consequently, the induction period was reduced and the rate of Ca(OH)2 formation in the accleration period was increased. The hydration of C3S in the system C3S-C3A was retarded because Al3+ in the liquid phase originating from the hydration of C3A was incorporated into calcium hydrosilicates formed. The retardation phenomenon of C3S hydration was not appeared in the system C3S-C3A-gypsum because the reaction of monosulfate formation became the rate-determining step.

• 대한건축학회논문집:구조계
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• 제34권3호
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• pp.53-59
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• 2018

When manufacturing self-healing concrete using bacteria, nutrients are added to increase the activity of the bacteria. Although many researches have focused on the effects of nutrients containing bacterial healing agent on concrete, few have studied the effects of sole nutrient on self-healing of cement composites. Bacterial nutrients, like commercial chemical admixtures, affect hydration characteristics such as flow, setting, hydration heat, mechanical strength of cement composites and also affect the self healing of cement composites by hydration of unhydrated particles. In this study, effect of the four nutrient commonly used in the existing literature on the hydration characteristics of cement composites by its addition was investigated. Flow, setting time, hydration heat, compressive strength have studied for each nutrients added by 1.5% and 3% of cement weight. Experimental results shows that urea and calcium-nitrate can be used up to 3% without significant detrimental effect on cement composites. Addition of calcium-lactate up to 1.5% show better compressive strength than control, but addition of 3% show almost non-hydration. Yeast extract shows detrimental effects on the composites regardless of the amount added.

• 한국세라믹학회지
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• 제27권8호
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• pp.1055-1063
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• 1990

The early hydration characteristics of the system $C_3S-C_3A-C_4AF$ according to the clinker composition variations, in order to establish the mutual interactionof clinker minerals during the portland cement hydration, have been studied. The early hydration rate of $C_3S$ was greatly effected by the change of $C_3S/C_3A$ ratio. The lower the $C_3S/C_3A$ ratio was, the faster the apex reaching time and the rate of heat liberation of the 2nd exothermic peak originating from the formation of $Ca(OH)_2$ were. The effect of $C_3S/C_3A$ ration on the amounts of $Ca(OH)_2$ formation was decreased, in process of hydration time, but the effect of $C_3S$ content was increased.

• 한국식품과학회지
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• 제35권4호
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• pp.660-665
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• 2003

은하콩과 태광콩의 수화속도 및 콩나물 생육 특성에 대한 동결처리의 효과를 수화반응에 대한 속도론적 연구와 콩나물의 재배실험을 통하여 조사하였다. 수화시간에 대한 동결처리의 영향은 침지온도에 따라 달랐는데, $60^{\circ}C$ 이하의 침지온도에서는 수화시간이 15-50% 정도 감소하였으며, $60^{\circ}C$ 이상의 침지온도에서는 수화시간이 감소하지 않았다. 동결 처리한 은하콩과 태광콩의 수화반응에 대한 활성화 에너지는 각각 39.79 및 39.25 kJ/mol로서 동결처리를 하지 않은 콩에 비해 약 20%정도 감소하였다. 은하콩과 태광콩은 동결처리에 의해 콩나물의 발아율, 길이 및 무게는 증가하였으며, 콩나물의 수율은 약간 감소하였고, 굵기는 콩의 품종에 따라 달랐다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.409-414
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• 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.