• Magazine of the Korea Concrete Institute
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• v.19 no.1
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• pp.87-93
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• 2007

• Magazine of the Korea Concrete Institute
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• v.10 no.6
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• pp.281-289
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• 1998

This study has been performed to test the flowability and filling ability of high flowing concrete as well as distribution of aggregate and pore of core specimen, heat of hydration, compressive strength and core strength of concrete. In addition, the resistance to chloride ion penetration and chemical solutionof concrete was tested in order to evaluate the resistance to sea water of concrete and its application of high flowing concrete using blended low heat cement in the field of Seohae Grand Bridge. The properties of high flowing concrete with blended low heat cement were compared with ordinary 25-240-15 concrete using Type V cement. As the results of this study, the flowability and filling ability of high flowing concrete with blended low heat cement is satisfied without vibration. Though the cement content of high flowing concrete with blended low heat cement was 400kg/m$^2$, the rising temperature of it was relatively lower than that of the ordinary 25-240-15 concrete with Type V cement. Also, the compressive of high flowing concrete with blended low heat cement is similar to that of the ordinary 25-240-15 concrete with Type V cement.

• Magazine of the Korea Concrete Institute
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• v.28 no.3
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• pp.50-53
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• 2016

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.133-139
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• 1996

As construction technology advances, most of civil engineering structures are becoming larger and taller. Therefore, high strength concrete is necessary for them. For high strength concrete, it needs a large amount of unit cement content and low water-cement ratio inevitably, so that a large amount of heat occurs in concrete. The thermal cracks make the durability and quality of concrete structures become worse, result from temperature rise and thermal stress due to heat of hydration. In this study, the proposal of using ground granulated blast furnace slag, fly ash and chemical admixtures was investigated to decrease the temperature rise of concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.357-364
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• 1997

In this experiment high-strength concrete of good workability is made by means of either replacing unit cement quantity to fly-ash by 20% or using low heat cement to reduce the internal hydration heat suggested as the fault of concrete. Concrete is poured through ready mixed concrete to test the ability of applying to the substantial works and is carried out the test of flowing and core strength and record of temperature of imitating specimens. It is capable to apply high-strength concrete replaced to fly-adh 20% to the substantial works through the experiment

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.385-390
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• 2001

The thermal crack in mass concrete is mainly due to the difference of concrete temperature, which is generated by hydration heat of cement. As the thickness of mat foundation increases, the difference of temperature becomes bigger. The purpose of this study is to estimate the optimum placing depth. The temperature of real mat foundation was observed and the thermal analysis by Finite Element Method was executed. Finally, the crack index according to the placing depth was estimated.

• Proceedings of the SAREK Conference
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• 2005.06a
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• pp.128-128
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• 2005

• Journal of the Korean Ceramic Society
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• v.27 no.8
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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.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.2
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• pp.135-142
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• 2009

This study investigates the characteristic properties of strength, flowability, durability and drying shrinkage to control strength and to reduce heat of hydration of high performance concrete using crushed stone fines. According to the experimental results, when crushed stone fines are increased every 10%, $10{\sim}15%$ of compressive strength is decreased and flowability of high performance concrete is effectively improved due to the decrease of modulus of deformation and confined water ratio. When crushed stone fines are replaced every 10%, $4^{\circ}C$ of the highest adiabatic temperature rise is decreased by reducing the unit cement. However, 5% of drying shrinkage is increased in the same condition In the meantime, durability of high performance concrete is excellent, having over 100% of good relative dynamic modulus of elasticity due to fineness of formation mused by the increase of the unit powder content and the improvement of flowability, without regard to the replacement of crushed stone fines. Therefore, It can be said that the usage of crushed stone fines can control the strength of high performance concrete by replacement and reduce heat of hydration.

• Solar Energy
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• v.17 no.1
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• pp.67-77
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• 1997

To develop chemical heat pump of higher energy density and efficiency heat-release characteristics accompanied by exothermic hydration reaction in packed bed, $Ca(OH)_2/CaO$ reactor, are examined in a lab-scale unit. We have studied the enhancement effect of inserted fins in cylindical packed bed reactor. The results obtained by numerical analysis about profiles of temperature, completion time of reaction and exothermic heat amount released from the reactor read the insertion of fins in reactor can reduce the reaction completion time by half and the rate of thermochemical reaction depends on the temperature and concentration, and it is also governed by the boundary conditions and the rate of heat transfer in the particle packed bed.