• Resources Recycling
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• v.9 no.3
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• pp.37-45
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• 2000

This paper presents the experimental test results on moisture and freeze-thaw resistance of hot mix crumb rubber modified (CRM) asphalt concrete mixture. To compare the differences in mechanical properties of conventional and CRM asphalt concretes, various tests were conducted under different moisture conditions and freeze-thaw cycles. Marshall mix design was also performed to determine the optimum asphalt contents for the both asphalt concrete mixtures. Test results revealed that the moisture and freeze-thaw resistance of CRM asphalt mixture was superior to the conventional asphalt concrete. As a result, it is considered that the utilization of waste tires in asphalt pavements has the potential of minimizing the damage due to the moisture and freeze-thaw.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.4
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• pp.269-275
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• 2000

It is well recognized that damage resulting from freeze-thaw cycles is a serious problem causing deterioration and degradation of concrete. In general, freeze-thaw cycles change the microstructure of the concrete ultimately leading to internal stresses and cracking. In this study, a new method for one-sided stress wave velocity measurement has been applied to evaluate freeze-thaw damage in concrete by monitoring the velocity change of longitudinal and surface waves. The freeze-thaw damage was induced in a $400{\times}350{\times}100mm$ concrete specimen in accordance with ASTM C666 using s commercial testing apparatus. A cycle consisted of a variation of the temperature from -14 to 4 degrees Celsius. A cycle takes 4-5 hours with approximately equal times devoted to freezing-thawing. Measurement of longitudinal and surface wave velocities based on one-sided stress wave velocity measurement technique was made every 5 freeze-thaw cycle. The variation of longitudinal and surface wave velocities due to increasing freeze-thaw damage is demonstrated and compared to determine which one is more effective to monitor freeze-thaw cyclic damage progress. The variation in longitudinal wave velocity measured by one-sided technique is also compared with that measured by the conventional through transmission technique.

• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.3
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• pp.70-80
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• 1989

In this research program special triaxial compression tests and dehydration-swelling tests under the condition of freeze-thaw process were conducted to show the effects of freezethaw process on the physical properties of weathered granite soil, and their results as follows; 1.Consolidation settlement of weathered granite soil mass was increased due to freeze-thaw process, and the initial tangent coefficient of dense state was higher than that of loose state. 2.Compression behaviour of soil was increased according to the decrease of freezing temperature, and when the freezing temperature was reached under - 10$^{\circ}$C, the compression rate was not influenced by change of freezing temperature. 3.The experiments showed that the void ratio and permeability of soil were converged into their values of shrinkage limit, and the permeability was higher due to the freeze-thaw process and as the lower the freezing temperature. 4.The decrease of liquid limit was indicated as the lower the freezing temperature, and as more the freeze4haw cycles, the moisture content was shown the lower side. 5.It was shown that the shrinkage was decreased by freeze-thaw process and not influenced by way of freezing temperature, but dehydration rate was higher.

• International Journal of Highway Engineering
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• v.17 no.2
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• pp.47-53
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• 2015

PURPOSES: The scaling of a concrete surface caused by the combined effects of frost and de-icing salts is one of the main reasons for the need to repair transportation infrastructures in cold-climate regions. This study describes the results of attempts to determine the scaling resistance of concrete incorporating mineral admixtures such as fly ash, GGBFS, and silica fume, and subjected to the actions of frost and salt. METHODS : Conventionally, to evaluate the fundamental properties of concrete, flexural and compressive strength measurements are regularly performed. Based on the ASTM C 672 standard, concrete is subjected to 2%, 4%, and 8% $CaCl_2$ salt solutions along with repeated sets of 50 freeze/thaw cycles, and the scaling resistance was evaluated based on the mass of the scale and a visual examination. RESULTS : It was observed that silica fume is very effective in enhancing the scaling resistance of concrete. Meanwhile, concrete incorporating GGBFS exhibited poor resistance to scaling, especially in the first ten freeze/thaw cycles. However, fly ash concrete generally exhibited the maximum amount of damage as a result of the frost-salt attack, regardless of the concentrations of the solutions. CONCLUSIONS: It can be concluded that the scaling resistance of concrete is highly dependent on the type of the mineral admixture used in the concrete. Therefore, to provide a durable concrete pavement for use in cold-climate regions, the selection of a suitable binder is essential.

• International Journal of Highway Engineering
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• v.12 no.3
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• pp.71-77
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• 2010

Anti-freezing layer does not used in case of non frost heaving in subgrade soils. In this case, the modulus of subgrade soils were varied with freezing and thaw cycles under non frost heaving. That effect should be properly considered in pavement design. Impact resonance test that is nondestructive testing method was used for continuously determining the modulus of subgrade soils during freezing and thaw cycle. The modulus of subgrade soils was identical with freezing and thaw cycles under closed freezing and thaw system which is no water supplement into specimen during testing. There was also no difference in the modulus of subgrade soil between before and after freezing-thaw cycles for all specimens with different water content and density. That is thaw-weakening of subgrade soils do not occur under closed freezing and thaw system. The moduli at freezing conditions are varied with water content and density, but it can be ignored in practical design sense.

• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.2
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• pp.43-53
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• 1989

In this research programs, a series test was conducted to show the effects of freeze/thaw process on the various soil properties. The tests were carried out taken from the west sea shore of Korean peninsular and the west sea shore of Scotland, and their results are as follows; 1. There was a positive total heave in a freezing run, although water may he expelled for the sample initially. The water flow must he reverse' from expulsion to intake. 2. The confining pressure had an overriding influence on the heave and frost penetration, a sudden change of the axial strain at failure with strain rate was observed occuring at a strain rate between 10-5 and 10-6, and the initial friction angle of frozen clay was appeared zero. 3. There was shown a significant decrease in liquid limit of soil which was subjected to freeze/thaw process for the initial value of about 20% because of soil particles aggregation. 4. The cyclic freeze/thaw caused a sinificant reduction in shear strength and its thixotropic regain. The frozen/thawed soil exibited negative strength regain, particularly at high freeze/thaw cycles. 5. The freezing temperature greatly influenced on the failure strength of soils and this. Trend was more pronounced the lower the freezing temperature and shown the ductile failure with indistinct peaks.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.640-643
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• 2009

The effect of the kind of gas diffusion layers (GDLs) on the freeze/thaw condition durability in polymer electrolyte fuel cells (PEFCs) were investigated. For this purpose, three kinds of GDLs, i.e., felt, paper and cloth types with different basic properties have been first prepared, then the changes in the properties and performance of cells was observed during the freeze/thaw cycles ranging from -30 to 70 $^{\circ}C$. The single cells consisting of different GDLs were evaluated for performance. The performance degradation and the cell resistance increase could be directly correlated. The physical destruction of electrode was shown by SEM analysis. It was presented that mechanical supporting force of interface between materials can help enhancing the durability of PEFCs in the freeze/thaw condition.

• Computers and Concrete
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• v.3 no.2_3
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• pp.163-175
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• 2006

This research was conducted to determine effect of pumice aggregate ratio, cement dosage and slumps on freeze-thaw resistance, density, water absorption and elasticity of concrete. In the first batch, $300kg/m^3$ cement dosage were kept constant and pumice ratios were changed as 25%, 50%, 75% and 100% of replacement for normal aggregate by volume for $3{\pm}1cm$, $5{\pm}1cm$ and $7{\pm}1cm$ slumps. Other batches were prepared with $200kg/m^3$, $250kg/m^3$, $350kg/m^3$, $400kg/m^3$ and $500kg/m^3$ cement dosages and 25% pumice aggregate +75% normal aggregate at a constant slump. Test results showed that when pumice-aggregate ratio decreased the density and freeze-thaw resistance of concretes increased. With increasing of cement dosage in the mixtures, density of the concretes increased, however, freeze-thaw resistance of concretes decreased. Water absorption of the concrete decreased with increasing cement dosage but increased with the pumice ratio. Water absorption of the concrete also decreased after freeze-thaw cycles. Freeze-thaw resistance of concretes was decreased with increasing the slumps.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.5
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• pp.487-490
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• 2011

We used X-ray tomography to carry out an experimental study to visualize the effect of freeze and thaw cycles on the gas diffusion layer (GDL) in a polymer electrolyte membrane fuel cell (PEMFC). A PEMFC has freeze and thaw cycles if the fuel cell is operating at a below-freezing ambient temperature. The cycle permanently deforms the fuel-cell capillary structures and reduces the ability of the cell to generate electric power and also reduces its service life. The GDL is the thickest capillary layer in the fuel cell, so it experiences the most deformation. The X-ray tomography facility at the Pohang Accelerator Laboratory was used to observe the structural changes in GDLs induced by a freeze and thaw cycle. We discuss the effects of these structural changes on the power production and service life of PEMFCs.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.2
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• pp.107-115
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• 2011

This research studies the behavior of the FRP-concrete interface subjected to two environmental substances. Frist is to investigate the behavior by the application of different bonding materials at the interface between FRP and concrete, second is to understand a long-term performance at the interface by Freeze-thaw actions. The parameters considered in this research are the maximum bonding strength and the effective bonding length at the FRP-concrete interface. In the first experimental phase, three types of specimens are fabricated and tested considering the number of applied bonding materials and the Freeze-thaw tests are performed to evaluate the behavior of the interface in the cycle range of 0 to 300 cycles. Finally, it is known that there is a 5~7% difference of the effective bonding length between applied bonding materials and the values for the maximum stress and the effective length under Freeze-thaw action are varied randomly as the freeze-thaw cycle is increased even though initial reduction of their capacities are occurred.