• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.489-492
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• 2008

Adiabatic temperature rise and autogenous shrinkage experiments were performed for three silica-fume included mass concrete mixtures and a reference mixture without silica-fume, in order to investigate the influence of silica-fume on the hydration heat and autogenous shrinkage properties of mass concrete, and to examine applicability of silica-fume to mass concrete. It was revealed from the experiment that, for mass concrete, the rate of hydration was hardly increased while the maximum adiabatic temperature rise decreased about 5$^{\circ}$C by the addition of silica-fume, and the amount of autogenous shrinkage was almost the same regardless of silica-fume replacement. These facts imply that silica-fume can enhance the resistance of mass concrete to temperature cracking as well as the durability.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.341-344
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• 1999

In the case of the offshore concrete structures like the anchorage block of a suspension bridge of Kwangan Grand Road, there is a need of the concrete which has low heat of hydration and good resistance for sea-water attack. In this study, the blended super low heat cement which satisfies that requirement was developed and several tests were carried out. The concrete using the blended super low heat cement showed lower adiabatic temperature rise than 3$0^{\circ}C$ and good early strength. Also, its passed charge(coulomb) to resist chloride ion penetration was very low.

• Journal of the Korean Ceramic Society
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• v.24 no.3
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• pp.289-295
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• 1987

The changes of physical properties of portland cement pastes and mortars were investigated by addition of sodium gluconate. Flow table experiment and viscosity measurement were took in order to find dispersing effect, and time-dependent changesof viscosity and rates of hydration heat evolution were carried out for the sake of finding retardation effect of hydration. And changes of physical properties of cement pastes and mortars were discussed by setting time, compressive strength and porosity.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.525-528
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• 2006

This study performed an experimental test to derive the characteristics of compressive strength, het of hydration and creep of roller compacted concrete. The main variable of strength test are cement content and fly ash content. The heat of hydration test was performed using MARUTO CH-50-CA and dreep test was carried out according to KS F 2453.

• Journal of the Korean Ceramic Society
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• v.36 no.6
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• pp.599-603
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• 1999

In an effort to improve the mechanical properties of the belite cement active belite cement clinker was synthesized. Properties of the clinker were characterized by a XRD, FT-IE optical microscopy and SEM. The additive effects of slag on the hydration properties were investigated by the measurement of compressive strength heat evolution and SEM. The experimental results exhibited that the 3wt% borax was effective in stabilizing $\alpha$'-C2S and the addition of 5wt% anhydrite and 40wt% slag wee effective in the hydration.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.264-269
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• 1996

Thermal cracks are occurred when thermal stress due to the hydration of cement exceeds the tensile strength of concrete. In this study, the thermal stresses are investigated at the massive concrete like an anchorage of suspension bridge. The thermal crack can be controlled by considering the placing height, concrete type, pre-cooling and pipe cooling in the design stage.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.05a
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• pp.57-60
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• 2008

This study investigated the results of insulation heat curing method using double layer bubble sheet in slab concrete and mass concrete in cold weather environment. First of all, when double bubble sheets are applied, it was shown that slab concrete was protected from early freezing by remaining between 6 and 15℃ even in case outside temperature drops -9℃ below zero until the 2nd day from piling, and in the case of mass concrete, with the maximum temperature difference between the center and surface less than 4℃, crack occurrence index was close to 2 and no hydration heat crack occurred by internal constraint. The insulation heat preservation curing method using the double bubble sheet applied in this field prevented early freezing owing to stable curing temperature management, deterring concrete strength development delay at low temperature, and obtained the needed strength. Also, it was proven that the method is highly effective and economic for cold weather concrete quality maintenance through curing cost reduction like construction period shortening and labor cost reduction, etc by reducing the process of temporary equipment installation and disassembling.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.315-318
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• 2009

본 논문에서는 해상 기초 교각 매스 콘크리트의 수화열 저감 방안을 다루었다. 저발열 콘크리트, Mesh형 거푸집 공법 등에 대한 실험을 수행하여 각각의 수화열 저감효과를 평가하였다. 현장 실험은 사용 시멘트와 거푸집의 종류, 거푸집의 사용 면수에 따라 총 4 type으로 구성하였으며, 이에 대한 실험 결과와 유한 요소 해석 결과를 비교, 검증하여 최종적인 수화열 저감 성능을 도출하고자 하였다. 실험을 통해, 저발열 시멘트와 유로폼을 사용하는 것이 수화열 저감을 위해 효과적인 방법으로 판명되었으나 추가 공사비의 발생으로 효율성이 떨어질 것으로 판단된다. 또한 Mesh형 거푸집 적용 면 수와 온도 상승 저감 효과는 비례하는 것을 알 수 있었지만 내 외부 온도차가 다소 크게 나타나 수화열에 의한 균열 발생 확률면에서는 다소 불리하게 나타났다. 그러나 실험 단계에서 생략된 양생과 관리를 통하여 균열의 저감효과를 거둘 수 있을 것으로 판단되며, 추가적으로 거푸집 해체 단계를 생략함으로 공기단축 측면에서 유리할 것으로 판단된다.

• Journal of the Korea Institute of Building Construction
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• v.3 no.1
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• pp.139-146
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• 2003

The special requirements of high-performance concrete(HPC) could be enhanced property over others such as compressive strength, durability, and construction practices. In order to satisfy these requirements a series of laboratory trial mixes and following mock-up test of reinforced concrete wall at field were performed in this study. The objective of this study was to quantitatively evaluate the workability, compressive strength, and the increased heat of hydration caused by the increase of the specific weight of cement according to various variables. Six example series designed about a minimum compressive strength of 500kgf/$\textrm{cm}^2$ at 28 days, and an approximately slump and slump flow of 25cm and 60cm respectively were tested. The selection process of the specific weight of water and the percentage of fly-ash transposition determined to be most suitable for the production of HPC is presented in the following paper.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.29-30
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• 2020

In this study, as part of the foundation for advancing the material compounding aspect to reduce hydration heat cracks in the mat foundation on which the mass concrete is constructed, the degree of concrete varieties of cement is used. The setting time was measured and comparative analysis was performed. Results It was confirmed that the concrete using LHC was more effective than the concrete using OPC in reducing the use of SP, the calorific value of the concrete was low, and it was more effective in preventing cracks. It is also terminated after 10 hours and it is determined that the use of LHC can reduce the cracks caused by the heat of hydration of the mat foundation.