• Journal of the Korean Recycled Construction Resources Institute
• /
• v.6 no.3
• /
• pp.79-87
• /
• 2011

Concrete incorporating high volume blast-furnace slag placed in cold weather regions might be in danger of initial frost damage because dependently on the mix proportions, the setting and the hardening would be remarkably delayed. Therefore, this study investigated to effect of the degree of frost on the strength development and the resistance to freezing and thawing of the concrete incorporating blast-furnace slag when being subjected to freeze at early age. As the experimental results, the concrete incorporating blast-furnace slag attacked by initial frost damage showed the remarkable reduction of both the compressive strength development and the resistance to freezing and thawing. Especially, the resistance to freezing-thawing of the concrete incorporating high volume blast-furnace slag became much lower than that of the normal concrete.

• Magazine of the Korea Concrete Institute
• /
• v.4 no.1
• /
• pp.89-96
• /
• 1992

It is generally known that the frost-resistance of concrete is much affected by the air content in concrete and by the air void system or air distribution. And also the frost-resistance is believed to vary with the stre¬ngth of concrete. This article is prepared to describe, based on experiment, the effect of the air content and the air void system, particularly the effect of the spacing factor, on the freeze-thaw resistance of the high strength conc¬rete. For this purpose, I first worked on Non-AE concrete to make its compressive strength set about 400 to 500 kg/em'. However, the freeze-thaw test on the Non-AE concrete resulted in low durability factor, I.e., 10-2~0%. Thus to enhance the durability, another supplementary step was needed. I used AE admixture. which enhanced durability by changing the air content from 2% to 12%. The frost-thaw test was then performed 500 cycles on the 20 kind of concrete mixtures which differ in unit cement content and in water-cement ratio. Keywords : frost -resistance, air content, air void system, air distribution, spacing factor, freeze-thaw test, dur ability factor. capillary cavity, Linear Traverse Method.

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

• Proceedings of the Korea Concrete Institute Conference
• /
• 1997.10a
• /
• pp.456-461
• /
• 1997

The purpose of this experimental study are to produce a durable concrete and to investigate the various factors that can deteriorate the concrete when freezing and thawing activity. Among the various factors that can influence the frost resistance of concrete, this study examined mainly the relationship of the frost resistance with the water-cement ratio, admixture and admixture replacement ratio and propose the available water-cement ratio, admixture and admixture replacement ratio.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2003.05a
• /
• pp.233-236
• /
• 2003

This study is intended to investigate the resistance of frost damage of concrete for planting, which recycled aggregate is used, by freezing in air and thawing in water. According to the results, if AE agent of 0.005% is mixed in making concrete for planting, it is thought that the resistance of frost damage is guaranteed in winter because concrete for planting is not under severe freezing and thawing function, but under natural weather action.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 1999.11a
• /
• pp.211-216
• /
• 1999

One of the problems in a refrigerator operation is the frost formation on a cold surface of the evaporator. The frost layer is formed by the sublimation of water vapor when the surface temperature is below the freezing point. This frost layer is usually porous and formed on the cold surface of the evaporator. The frost layer on the surface of a evaporator will make side effect such as thermal resistance. However, these important factors have not been used in determining the defrosting period. In this report, a prediction taking into account the change of the fin efficiency due to the growth of the frost layer.

• Journal of the Korea Concrete Institute
• /
• v.16 no.2 s.80
• /
• pp.269-275
• /
• 2004

Factorial design method is applied to investigate the effects of various factors simultaneously rather than to conduct a series of single-factor experiment. As the results, frost resistance of the concrete specimens, in both W/C ratio of 0.28 and 0.35, was highly affected by the type of coarse aggregate that is, andesite produced more durable concrete than the limestone. Durability factor of the specimens, with W/C ratio of 0.28, which were demolded after I day and transferred to the curing room was higher than those demolded after 2 days. This stated the efficiency of the high early curing in high strength concrete.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2015.05a
• /
• pp.44-45
• /
• 2015

Although the carbonation problem of high-volume slag concrete has been solved by the mixed use of emulsified refine cooling oil as the pilot study, there was an instance of securing air quantity and frost resistance followed by the use of Expancel due to the problem of having vulnerability in frost resistance in result as the air quantity has not been secured. But due to the problem of Expancel not being economical, air quantity and frost resistance of high-volume slag concrete mixed with ERCO are attempted to be secured using micro bubble that can remain in the water for a long time as a relatively economical and very microscopic bubble.

• Journal of the Korea Concrete Institute
• /
• v.13 no.2
• /
• pp.139-145
• /
• 2001

One of ways to make high-strength concrete is for the mix contain particles graded down to the finest size : this is achieved by the use of fly ash, silica fume which fills the spaces between the cement particle and between the aggregate and the cement particles. And, the mix needs a sufficient workability. This is achieved by the use of a superplasticizer. This study is to investigate frost resistance of high-strength concrete at early age, with ratio of tensile strength and recovery of compressive strength, when high-strength concrete is placed in cold climates. According to this study, it is necessary to ensure 4 % of air content, 5 kgf/$\textrm{cm}^2$ of tensile strength, at least, for frost resistance of high-strength concrete at early age.

• International Journal of Concrete Structures and Materials
• /
• v.11 no.2
• /
• pp.315-325
• /
• 2017

The purpose of the paper is to determine the influence of two widely used steel fibers and polypropylene fibers on the sulphate crystallization resistance, freeze-thaw resistance and surface wettability of ultra-high performance concrete (UHPC). Tests were carried out on cubes and cylinders of plain UHPC and fiber reinforced UHPC with varying contents ranging from 0.25 to 1% steel fibers and/or polypropylene fibers. Extensive data from the salt resistance test, frost resistance test, dynamic modulus of elasticity test before and after freezing-thawing, as well as the contact angle test were recorded and analyzed. Fiber hybridization relatively increased the resistance to salt crystallization and freeze-thaw resistance of UHPC in comparison with a single type of fiber in UHPC at the same fiber volume fraction. The experimental results indicate that hybrid fibers can significantly improve the adhesion properties and reduce the wettability of the UHPC surface.