• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.241-242
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• 2021

In this study, we develop the damage depth diagnostic technology of fire damage concrete and propose an method of impaired depth due to fire by drying impaired concrete after immersing. Test results indicated that when assesing impared depth due to fire with the dry method after water immersing, impaired depth was clearly found and furthermore, compared with that by Phenolphthalein method 10 mm of damage depth was additionally identified, which is imposible to asses when Phenolphthalein is applied.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.245-246
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• 2021

In this study, we develop the damage depth diagnostic technology of fire damage concrete and propose an method of impaired depth due to fire by drying impaired concrete after immersing. Test results indicated that when assesing impared depth due to fire with the dry method after water immersing, impaired depth was clearly found and furthermore, compared with that by Phenolphthalein method 15 mm of damage depth was additionally identified, which is imposible to asses when Phenolphthalein is applied.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.243-244
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• 2021

In this study, we develop diagnostic technology for damage depth of fire-damaged concrete and propose methods for damage caused by fire by drying damaged concrete after immersion. As a result of the test, the damaged depth was clearly found when evaluating the depth of impurities caused by fire in a drying method after water had permeated, and it could be verified using thermogravimetric analysis.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.65-66
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• 2017

Early-frost damages easily take place in smaller and thinner walls and slabs. In case of slabs, it is difficult to visually determine the depth of early-frost damage. As such, the current study aims to determine the depth of early-frost damage caused to concrete structures due to bad curing in the winter. As a result, the study found that the depth of early-frost damages increased from the top as the atmospheric temperature on the concrete surface decreased. The changes in the color allowed the observer to easily identify the depth of early-frost damage with the naked eye. In particular, the color difference between potentially damaged parts and undamaged parts were the greatest around thirty minutes of drying after wetting.

• Journal of the Korea Institute of Building Construction
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• v.3 no.3
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• pp.73-81
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• 2003

In this paper, salt damage resistance of high durable concrete was tested. High durable concrete was made by using low water cement ratio, chemical admixture called super-durable admixture and mineral admixtures such as fly-ash, ground granulated blast-furnace slag, silica fume. Two kinds of salt damage resistance test were carried out. One method is chloride ion penetration test(ASTM C1202), and the other one is depth of chloride penetration test in saline solution. Test results were as followers: 1) The depth of chloride ion penetration increased exponentially as water cement ratio was increased and time passed. 2) Super-durable admixture had little effect on the improvement of salt damage resistance of concrete. 3) Silica fume and ground granulated blast-furnace slag were effective on salt damage resistance because of pozzolanic reaction, but fly-ash had a little effect.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.207-208
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• 2017

The current study assumed a condition in which concrete curing was not completed correctly in the winter, in order to analyze the effect of changes in early low-temperatures in early-frost damage depth. As a result, lower external temperature early on after depositing the concrete greatly reduced the temperature in the upper parts of the concrete, and it delayed the time during which the concrete temperature restored. In addition, for early-frost damages, lower early temperature increased the expansion of frozen water, which in turn relaxes the concrete structures and increases the absorption rate, ultimately extending the depth of early-frost damage.

• Journal of the Korea Institute of Building Construction
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• v.24 no.3
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• pp.297-308
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• 2024

This study presents a novel approach for evaluating fire-induced damage depth in concrete. The methodology leverages the principle that exposure to high temperatures causes internal expansion within concrete, leading to increased voids and microcracks in the damaged zones. This heightened porosity results in greater absorption rates compared to undamaged areas. By immersing fire-damaged concrete samples in water and subsequently monitoring the drying process, the depth of damage can be assessed. Differences in drying rates and color variations between damaged and undamaged areas serve as visual indicators for determining the extent of the damage. Experimental results from this water immersion method revealed damage depths of 38.7mm and 37.5mm for two different concrete mixtures. These measurements notably surpass the damage depths estimated using traditional phenolphthalein-based methods. This discrepancy suggests that utilizing the absorption rate principle, which is directly linked to the physical changes caused by thermal expansion, offers a more accurate and sensitive assessment of fire damage depth compared to methods relying solely on the presence of Portlandite for colorimetric indication.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.167-168
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• 2020

In this study, we attempted to present a method for diagnosing the depth of the early frost damage concrete using organic pigments under the cold weather. As a result, it is considered that the organic pigment did not penetrate into the voids of the concrete that had been damaged by the early frost damage and only the surface was adhered. Therefore, when fine particles that can be melted in water and pass through voids are used, it is analyzed that it can penetrate damaged part of the concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.145-146
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• 2018

In this study, the purpose of the study is to determine the depth of damage caused by early frost damage in concrete slab structures under the conditions of external temperature during winter. In other words, we intend to analyze the depth variation of the early frost damage as the thickness of the normal strength concrete slab members changes. As a result, the thinner the component was, the deeper the early frost damage was found to be, and the resulting increase in brightness of the concrete was delayed. and It is analyzed that under this test condition, an early frost damage was created with a thickness of 50 mm for the member and a thickness of 39 mm for the member of 300 mm.

• Journal of the Korean Geosynthetics Society
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• v.22 no.1
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• pp.97-107
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• 2023

This study analyzed the causes of frost damage and freezing depth for concrete ballast sites in the Gangwon mountainous area, which has a high freezing index, and considered the equation for freezing depth in concrete roadbeds. Comparing the freezing depth tendencies of concrete roadbeds in the Gangwon mountainous area and Gangwon area, it was found that the freezing depth of concrete roadbeds was higher than that of the Gangwon area when the freezing index was less than 400. However, in sections with a freezing index greater than 400, the freezing depth was higher in the Gangwon area than in the concrete roadbeds. This study proposed an equation for computing the freezing depth in the Gangwon area to provide basic data for establishing preventive measures against frost damage during railway and road construction projects in the Gangwon region.