• Journal of the Korean Society for Railway
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• v.19 no.4
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• pp.506-514
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• 2016

Experimental ballast track and concrete track were installed on the railway site and the frost penetration depth and the frost heave amount in the winter were measured. As a result, when the freezing index was the same, the frost penetration depth of concrete track was deeper than that of ballast track. Furthermore, when an XPS and polyethylene aggregate layer was installed below the ballast track, the frost penetration depth of the ballast track decreased significantly; in the case of the concrete track, the frost penetration depth decreased when the thickness of the subbase increased. Meanwhile, the frost heave amount also decreased when an XPS and polyethylene aggregate layer was installed below the ballast track ; in the case of the concrete track, the frost heave amount decreased when the thickness of the subbase increased.

• Journal of the Korean Geotechnical Society
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• v.33 no.3
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• pp.49-62
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• 2017

In order to understand response of geo-structures to the freezing-thawing process in the ground, it is necessary to consider phase change of the pore water of the ground and also to understand soil interaction with structures. In this study, numerical analysis was carried out for freezing and thawing effect on the modular road system. Neumann's theoretical equation for freezing-thawing processes in porous media can be used to estimate frozen depth and heaving from basic soil properties and ground and surface temperature, but its application is limited to the case for the sediment with fully saturated condition and zero unfrozen water content. Numerical analysis of the modular road system was performed on various soil types and different ground water table as the varying freezing index. The amount of heaving in the silty soil was much larger than those in granite weathered soil or sandy soil, and lowering groundwater level reduced ground heaving induced by freezing. Numerical analysis for temperature history of the ground surface predicted residual heaving near the surface by the freeze-thaw process in silty soil. It ought to reduce stiffness and bearing capacity of the ground so that it will impair stability and serviceability of new road system. However, the amount of residual heaving was insignificant for the road system installed in weathered soil granite and sandy soil. Since modular road system is a pavement structure mounted on the supporting substructure unlike the prevalent road pavement system, strict criteria should be applied for uniform and differential settlement of the pavement system.

• International Journal of Highway Engineering
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• v.5 no.2 s.16
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• pp.37-47
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• 2003

The basic study was performed on the mechanical analysis of frost and heave using program FROST by CRREL, U.S. army corps of engineers. The characteristics of frost heaving in pavement was analyzed by considering climate, pavement sections and subgrade soil conditions in Korea. Water tables were located at the depth of 0.35m, 2m and 3.35m from subgrade. Inputs were evaluated inevitably from the existing references. As a result frost heave and depth were evaluated with respect time. Maximum frost heave decreased lowering the water table and maximum frost depth was less than 15cm from subgrade. Frost action did not affect seriously on the analysis sections.

• Journal of the Korea Concrete Institute
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• v.17 no.5 s.89
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• pp.703-708
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• 2005

The effects of polymer-cement ratio and antifoamer content on the setting time and durability of high-fluidity polymer-modified mortars using redispersible polymer powder are examined. As the result, the setting time of the polymer-modified mortars using redispersible polymer powder tends to be delayed with increasing polymer-cement ratio, regardless of the antifoamer content. The water absorption, chloride ion penetration depth and carbonation depth of the high-fluidity polymer-modified mortars using redispersible polymer powder decrease with increasing polymer-cement ratio and antifoamer content. The resistance of freezing and thawing and chemicals improvement is attributed to the improved bond between cement hydrates and aggregates because of the incorporation of redispersible polymer powder

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.181-182
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• 2016

We developed eco-friendly lightweight concrete in order to apply eco-friendly lightweight concrete into structural wall or slab of shallow depth urban railway system. However, since lightweight aggregate has different structural feature of porous and it has been overvalued at current KS standard when applied, we did compare the characteristics of freezing and thawing of normal weight aggregate concrete by comparative test method(KS, ASTM). According to test method, there was a big difference of dynamic elastic modulus in lightweight concrete rather than in normal weight aggregate concrete. The big absorption factor in lightweight aggregate is main reason for that. For more detail, in KS law in which only 14 days water curing is carried out, the big amount of moisture in lightweight aggregate is frozen and high heaving pressure occurs and finally that lead to destruction of lightweight concrete. Therefore, it is considered that in case of lightweight concrete, resistibility against freezing and thawing has been undervalued in domestic KS law compared to ASTM law, which is overseas standard. So, a variety of examination about testing criteria and rule would be necessary for exact assessment of lightweight concrete.

• Geomechanics and Engineering
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• v.38 no.2
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• pp.205-214
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• 2024

Permafrost refers to the condition where the ground is frozen. It is crucial to review and evaluate the ground's characteristics before construction. In this study, electrical resistivity surveying is chosen as the investigative technique to apply and illustrate the results on the state of permafrost ground and to summarize its applicability. Field experiments are conducted in the Yeoncheon area of South Korea, which has a freezing index of 522.6°C·days. The target area is categorized into two ground conditions: the first where the original ground freezes, and the second involves excavating the original ground up to a depth of 3 meters, backfilling it, and then artificially injecting fluid. Thus, frozen ground conditions are simulated under both natural and artificial circumstances. Electrical resistivity surveys are performed under both above-freezing and sub-zero temperature conditions, with the experiments conducted at sub-zero temperatures revealing relatively more high-resistivity zones due to the temperature conditions. In this area, the distribution of soil moisture content is also investigated using the Time Domain Reflectometry (TDR) technique. It is observed that the ground into which water is artificially injected had a relatively higher moisture content, although the difference is minor. Finally, a 3D map of the target ground is constructed based on the measured electrical resistivity values, and through this, the distribution of porosity, a crucial design parameter, is also depicted. This research demonstrates that the electrical resistivity technique can effectively evaluate the state of frozen and unfrozen ground and further suggests that it can detailed extract the characteristics of the target ground.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.43-46
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• 2009

The purpose of this study is to enhance durability of concrete structures that uses this surface protecting material by carrying out the performance test of the surface protecting material of concrete, and as s result, we reached out the conclusion as follow. 1. As a result of the test measuring the stability and adhesive power of conductive film against ultraviolet, freezing & thawing, and damage from seawater that deteriorate the surface protecting material, it was turned out to meet the performance criteria specifying in the KS standard enough to gain a good evaluation to use as a surface protecting material. 2. As a result of the test identifying the neutralization-furtherance, it was assessed to be capable of protecting effectively concrete structures from carbonic acid gas by a very low depth of 0.1mm of neutralization. 3. As a result of the test identifying Penetrated Resistance Properties of chloride ion, as it was turned out to have a very low value of 819 Coulombs, it was assessed that even in the environment where the corrosion by chloride such sea environment is very affective, the film can effectively protect the concrete structure. 4. As a result of the test identifying freezing & thawing, as there was no change in reduction of mass after 400 cycle, it was assessed that the film has a good resistance against freezing & thawing. According to the results of study above, it is expected that this technology can extend its durability of concrete structure and be widely used for concrete structure through means (methods) to prevent the neutralization and damage from seawater as original purposes of the surface protecting material.

• Journal of the Korean GEO-environmental Society
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• v.10 no.4
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• pp.15-24
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• 2009

Korea is known to have seasonal frost during winter and the effect of low temperatures and water may cause a weakening of pavements. For that reason, frost protection layers have been constructed in pavements to avoid damage caused by frost action. The practies established in USA and Japan have been adopted as anti-frost design methods in Korea. However, the characteristics of Korean soils are different. Additionally, there is no formulation of a reasonable equation for frost penetration depth and the criterion to identify potentially frost-susceptible soils in present pavement design manuals in Korea. Therefore, adequate pavement design procedures in seasonal frost areas, as well as construction and maintenance practices are required. In this paper, frost penetration depths along national roads in Korea were measured and analyzed over several years. The frost penetration depth was analyzed with respect to the provinces of Korea and sunny/ shaded areas. Additionally, measurement results were compared to the formula of the US Army Corps of Engineers and Ifukube in Japan.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.5
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• pp.31-39
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• 2013

In this study, performance of the post-installed anchor system was evaluated with reduced strength of concrete and anchor. One of the post-installed anchors was selected to performance evaluation. Concrete strength was reduced by freeze-thawing test, and the post-installed anchor strength was reduced by corrosion test. The post-installed Anchor was installed in concrete of freezing and thawing and original concrete, and corroded anchor was installed in original concrete only. Anchor diameter and installation depth of the anchor were the variable for each specimen. Performance of post-installed anchor system of each specimen was evaluated by pullout test. Anchor diameter and installation depth of anchor, it may affect the performance of the post-installed anchor system from the experimental test results. Fracture mode of each post-installed anchor system had occurred differently depending on the durability of concrete and anchor. The anchor pullout strength from the experimental test results was used in order to compare with the results of CCD (Concrete Capacity Design) method, and CCD equation was modified. Modified equation was able to predict the anchor pullout strength of post-installed anchor system in Original concrete and freezing and thawing of concrete.

• Geotechnical Engineering
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• v.14 no.1
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• pp.49-58
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• 1998

It was investigated whether the scrap tire can be recycled as a construction material for controlling the frost heave of the ground. Some frost heave tests and a frost penetration depth test in the laboratory were performed on the weathered granite soil mitred with variable amount of scrap tire powder under the atmospheric temperature at -$17^{\circ}$ to find the basic effects of the scrap tire on the control of frost. The frost heave control layer of the crushed stone mixed with scrap tire chips directly below thin subbass in the bituminous pavement was found to be effective for practical use. And the equation for the required thickness of this frost heave control layer with freezing index was suggested.