• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.349-352
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• 1999

Concrete cracks due to hydration heat are a serious problem, particularly in mass concrete structures such as box rahmen, dam or footing of pier, etc.. As a result of the temperature rise and restriction condition of foundation, the thermal stress which may induce the cracks can occur. In this, study, ABAQUS program package was used to calculate the temperature distributions generated by hydration heat and the thermal stress in box rahmen structure which have thickness of 1.7~2.2m, and applied for various equations of adiabatic temperature rise such as korean code, japanese code, convection coefficient and low heat cement code.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.329-333
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• 1995

The usual methods for the temperature control of mass-concrete structures include the use of low-heat cement, pre-cooling, or pipe-cooling. In order to control the heat of hydration of mass-concrete structures such as massive pier or anchor block, and mat foundation, the pipe cooling method is widely acceptable for pratical use. In this paper, method of analysis using the Finite Element Method was applied to analyze the heat exchange on the field of three dimensional thermal conduction. The result of analysis Well agreed with experimentally measurement data by "KUMATANI". The method of this analysis will be used widely to control the heat of hydration by the pipe cooling in mass-concrete.-concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.380-386
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• 1996

This paper presents the history of heat hydration and the core strength of underwater non-segregation concrete. Three types of cements including Type I, Type V and low-heat cement have been used to make the mass specimens for measurement of heat of hydration and also for coring. Two environments of ambient and underwater conditions have been accounted for the comparison of producing the heat of hydration and for the assessment of core strength in respect to the test specimens made under normal practice.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.171-172
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• 2022

This study aims to develop the hydration heat reducing material (powder type) to lower the heat of hydration of mass members in the extremely hot weather condition. In this study, we applied the developed material to the concrete that used two kinds of binders with cement and evaluate the concrete properties with it.

• Journal of the Korea Concrete Institute
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• v.24 no.6
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• pp.659-666
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• 2012

To secure the thermal crack resistance of mass concrete, researches and the field applications of low heat portland cement (LPC), ternary blended cement (TBC) which is produced by blending ordinary portland cement with blast furnace slag and fly ash, and early strength low heat blended cement (EBC) increased in recent years. Although the model for adiabatic temperature rise is necessary for estimating the risk of thermal cracking of concrete structures, sufficient data have not been accumulated for these mixtures. In addition, the differences in adiabatic test results have been reported for the volume of test specimens. Therefore, the present study evaluated the characteristics of adiabatic temperature rise based on the type of binder and the volume of the adiabatic test specimen. Test results indicated that the maximum temperature rise ($Q_{\infty}$) and the reaction factor (r) of TBC were the lowest. Test results also showed that $Q_{\infty}$ and r changed with respect to the volume of test specimen. $Q_{\infty}$ and r obtained from 6l equipment were lower than those of 50l equipment. Therefore, corrections with respect to this phenomenon was confirmed and the corrections factors are presented.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.889-892
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• 2008

This study, having combined and displaced fly ash known as admixture material that delays hydration reaction with coarse particle cement("CC" hereinafter) collected in particle classification method during ordinary portland cement("OPC" hereinafter), reviewed the hydration heat characteristics affecting the concrete. To reduce hydration heat, the study plain-mixed which used 100% OPC for WB 50% level 1, displaced CC at level 3 of 25%, 50% and 75% for OPC, and by displacing FA with admixture material at level 5 of 0%, 10%, 20%, 30% and 40%, experimented totally 16 batches. As a result of experiment, in the case of flow, the more CC displacement rate increased, the more it tended to decrease, and the more FA displacement rate increased, the more it decreased. As for simple adiabatic temperature rise by the CC and FA displacement rates, it decreased as displacement rate increased, and particularly in the case of FA40, temperature rise amount, $5.8{\sim}7.4^{\circ}C$, was very low. Compressive strength decreased in proportion to displacement rate, however strength reduction increment was shown to decrease with age progress.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.641-644
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• 2006

Considering properties of the low-heat concrete mixed with the blended cements, the influences compared blended cements with ordinary portland cement made experiments on. (1) Blended cements were superior to OPC in the fresh concrete flow that the use of blended cements reduced chemical admixture. (2) The more the use of additive increase, the more bleeding happens. So it is considered to heights, order, and rate of placement, curing methods and so on. (3) The use of blended cements increase long term strength after 28 days, but decrease early strength and durability. So it is considered to the curing methods and early frost damage, and endurance limit.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.215-216
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• 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.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.505-508
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• 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.

• Journal of the Korea Concrete Institute
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• v.13 no.2
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• pp.175-183
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• 2001

Immersion tests with artificial seawater were carried out to investigate the resistance to seawater attack of 5 types of cement matrices. From the results of compressive strength and length change, it was found that blended cement mortars due to mineral admixtures, were superior to portland cement mortars with respect to the resistance to seawater attack. Moreover, XRD analysis indicated that the peak intensity ratio of low heat portland cement(LHC) paste, in portland cement pastes, had better results, and so did that of blended cement Paste. Pore volume of pastes by mercury intrusion porosimetry method demonstrated that total pore volume of ordinary portland cement(OPC) paste had a remarkable increase comparing with that of other pastes. In case of immersion of artificial seawater, the use of ground granulated blast-furnace slag and fly ash, however, showed the beneficial effects of 56% and 32% in reduction of total pore volume, respectively.