• International Journal of Highway Engineering
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• v.11 no.4
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• pp.127-132
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• 2009

This study presents the test results on the compaction characteristics of warm mix asphalt mixtures that include the additive in 3 different mixtures(hot mix asphalt, SBS and SMA). The tests were conducted to find out the compaction characteristics on the compactability with varying compaction time, different amount of the warm mix additive and lowering the compaction temperature. The Superpave gyratory compactor was used to find out the variation of the density when the number of the gyration is varied. A dense mixture and 3 different warm mix additives were employed to find the relationship between compactability and compaction time. The comparison of the compactability with lowering the temperature was conducted using dense mixture, SBS polymer modified mixture and stone matrix asphalt mixture(SMA). The difference of the density of warm mix asphalt mixtures was not found due to the lowering of compaction temperature when it was compared with the standard mixture and the warm mix showed the stable condition in density. In the mean time, depending upon the different warm mix additive and mixture, the difference of density and the variation trend of compaction is found to be existed and shows the relationship between these two variables.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.513-516
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• 2006

Waste concrete powder(WCP) is a secondary by-product generated while processing waste concrete manufactured to coarse and fine aggregates for concrete. In order to assess the possibility of using WCP as admixture for self-compacting concrete, self-compactability, compressive strength and durability of self-compacting concrete containing waste concrete powder were investigated. Experimental results of this study appeared that in case of SCC mixed with WCP only, self-compactability and compressive strength decreased with increasing mixing ratio of WCP. When Blast-furnace slag(BFS) was added to SCC, self-compactability and compressive strength for a unit amount of cement increased. Also, SCC containing 15% BFS and 15%, 30% and 45% WCP, the dry shrinkage and carbonation depth appeared a tendency to decrease with increasing mixing ratio.

• Journal of Powder Materials
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• v.23 no.6
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• pp.426-431
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• 2016

The Fe-Cr-Al alloy system shows an excellent heat resistance because of the formation of an $Al_2O_3$ film on the metal surface in an oxidizing atmosphere at high temperatures up to $1400^{\circ}C$. The Fecralloy needs an additive that can act as a binder because of its bad compactability. In this study, the green compacts of STS434L and Al powder added to Fecralloy are oxidized at $950^{\circ}C$ for up to 210 h. Fecralloy and Al is mixed by two types of ball milling. One is vented to air and the other was performed in a sealed jar. In the case of Al addition, there are no significant changes in the electrical resistance. Before the oxidation test, Al oxides are present in the Fecralloy surface, as determined from the energy dispersive spectroscopy results. The addition of Al improves the compactability because of an increased density, and the addition of STS434L increases the electrical resistivity by forming a composite oxide.

• Journal of the Korea Institute of Building Construction
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• v.12 no.4
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• pp.451-459
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• 2012

At the Korea Land and Housing Corporation(LH), concretes with high design strength of 50 MPa and 80 MPa that are composed only of ordinary Portland cement, blast furnace slag, and fly ash are developed. To determine whether the developed high strength concretes have the same properties when they are produced in batch plant(B/P) condition in the ready mixed concrete plant, and as existing high strength concretes, field tests are performed and material properties are evaluated. To investigate the material properties of the high strength concretes before and after pumping, compressive strength, flowability, air content, hydration temperature, pumping and compactability are evaluated. In field tests, before and after pumping, flowability satisfied the relevant criteria. In terms of air content, while it was slightly decreased after pumping, it satisfied the requirements. Hydration temperature criteria were satisfied, and compactability was excellent as well. The study found that the developed ternary high strength concretes have the same properties as existing high strength concretes. They can also be useful for the construction of high-rise buildings, as they are economical.

• Journal of Korea Foundry Society
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• v.7 no.3
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• pp.199-206
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• 1987

This paper presents experimental data for the computerization of green sand control. The results can be summarized as follows: 1. To obtain the proper compactability at the mixer, the addtion of moisture is far more efficient than the control of mixing time or addtion of clay. 2. The log R(% clay/% moisture) vs. log compactability curve moves upward as the amount of clay increases and moves downward as the amount of seacoal, dead bentonite or coked seacoal increases. 3. The ratio of dead to initial clay amount or coked to initial seacoal amount is changed according to sand to metal ratio, mainly, and according to pouring temperature, partly, at a shake out time of 12hrs.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.755-758
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• 2004

Self-compactability is defined as a capability of concrete to be uniformly filled and compacted in every corners of formwork by its self-weight without vibration during placing. To evaluate the self compactability of self compacting concrete, the slump flow, the time of slump flow at 500mm and U-box apparatus testing methods are used. In this research, the fresh and hardened properties of self compacting concrete using ground granulated blast furnace slag as a part of cement were investigated for the volume contents of sand in the mortar. The workability, flowing characteristics, air content and compressive strength of concrete were tested and the results were compared with the different volume contents of sand in the mortar. In the experiment, we acquired satisfactory results at the point of flowing characteristics and strengths of self compacting concrete.

• Journal of Korea Foundry Society
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• v.3 no.3
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• pp.167-173
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• 1983

The effect of sand grain size on the various properties of mold is not only basic but important interest which we have to deal with.And the relation among the various properties of mold (strength, permeability, flowability, compactability, hardness, deformation, toughness etc.) is very complicated and inaccurate, so we can delineate the behavior of mixture (sand+water+bentonite) with experience only. Within recent years a so-called rigid-water theory has been accepted as a means of advancing logical explanations for the research aimed at delineating sand-clay-water relationships. By changing grain size or mesh no. of grain, specimens have been subjected to green compressive strength, permeability, deformation, flowability, compactablity, toughness at room temperature. Under constant mulling energy and ratio of water/bentonite, the results obtained were as follows: 1. With decreasing grain size green compressive strength of the specimen increased. 2. With decreasing grain size permeability decreased. 3. With decreasing grain size flowability and bulk density decreased but compactability increased. 4. With decreasing grain size deformation decreased but toughness increased. 5. At 60 mesh no., the properties of specimen are conspicuously changed. The reason is that the total surface area of sand grain which affects the type of bonding between sand grains is more changed at 60 mesh number.

• Journal of Korea Foundry Society
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• v.4 no.1
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• pp.5-11
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• 1984

Green compressive strength, permeability, deformation, flowability, compactability and green hardness values at room temperature are dependable on the grain distribution and grain shape. The results obtained under constant moisture (4% for sand) and bentonite (8% for sand) were as follows; 1. With decreasing grain size, surface area of sand grain was increased. 2. With decreasing grain size, coefficient of angularity was increased. 3. As surface area increased from $8926.43cm^2$ to $21211.16cm^2$ , green compressive strength was increased from $210.93\;g/cm^2$ to $449.98\;g/cm^2$, hardness was increased from 76.7 to 82.3, but permeability was decreased from $411.7\;{\frac{\;cc\;{\cdot}\;cm\;}{atm\;{\cdot}\;cm^2\;{\cdot}\;min.}}$ to $113.7\;{\frac{\;cc\;{\cdot}\;mm\;}{atm\;{\cdot}\;cm^2\;{\cdot}\;min.}}$ 4. As surface area increased from $8926.43\;cm^2$ to $21211.16\;cm^2$, flowability was decreased from 82.3% to 80.8%, deformation was decreased from $67.1\;cm\;{\times}\;10^{-3}$ to $54.6\;cm\;{\times}\;10^{-3}$, but compactability was increased from 44.8% to 54.3%. 5. Room temperature properties of molding sand were affected by variation of surface area.

• Magazine of the Korea Concrete Institute
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• v.8 no.2
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• pp.109-117
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• 1996

Recently, High-Workable Concrete has been developed and began to be used to a great extent in foreign countries, but it is not familiar with and fully Introduced in Korea yet. Therefore the aim of this paper is to suggest a reference data. for the development of High-Workable Concrete according to the comparative analysis which were done on the effects of mix proportion(water-binder ratio, sand-aggregate ratio, unit water, a kind of superplasticizer) on the flowing characteristics. And also this paper aims to examine the compactability and segregation resistance of High-Workable Concrete in a mock-up test and in a field test. From the result, we concluded that it is possible to produce and to use the High-Workable Concrete at the construction site.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.50-55
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• 1995

Recently, high-workable concrete has been developed and began to be used to a great extent in foreign countries, but it isn't familiar with and fully introduced in Korea yet. The aim of this paper is to suggest a reference data for the development of High-workable concrete according to the comparative analysis the effect of mix proportion (unit water sand/aggregate ratio) on the flowing characteristics. And also this paper aims to examine the compactability of High-workable concrete in a model wall-form.