• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.567-572
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• 2002

This research investigates experimentally an effect on the quality performances of the high flowing concrete according to binder types. The purpose of this study is to determine the optimum mix proportion of the high flowing concrete having good flowability, viscosity and no-segregation. For this purpose, two types using belite cement＋lime stone powder(LSP) and furnace slag cement+lime stone powder are selected and tested by design factors including water cement ratio, fine and coarse aggregate volume ratio. As test results of this study, the optimum mix proportion for binder types is as followings. 1) One type based belite cement ; water cement ratio $51^{\circ}C$, fine aggregate volume ratio $43^{\circ}C$ and coarse aggregate volume ratio $53^{\circ}C$, replacement ratio of LSP $42.7^{\circ}C$. 2) Another type based slag cement : water cement ratio $41^{\circ}C$, fine aggregate volume ratio $47^{\circ}C$ and coarse aggregate volume ratio $53^{\circ}C$, replacement ratio of LSP $13.5^{\circ}C$.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.269-274
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• 2001

The purpose of this study is to evaluate basic properties of artificial aggregate using concrete sludge according to mixing ratio. Cement, waste phosphogypsum and Powder of blast furnace slag are used with binder of artificial aggregate. Specific gravity, absorption are tested for basic property, and impacting, abrasion and crushing tests are done for characteristics of strength on the aggregate, including comparison with crushed stone. Bry specific gravity was ranged about 1.16 to 1.30 the test result of the aggregates and shape is round In the result of tests, it is concluded that qualities of the aggregates using concrete sludge are slightly lower than crushed stone but it is similiar with sintering artificial lightweight aggregate in high temperature.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2004.05a
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• pp.51-55
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• 2004

Generally, aggregate may limit the strength of concrete, and aggregate with undesirable properties including strength, shape and grading etc. cannot produce good concrete. Also, the properties of aggregate greatly affect the durability and structural performance of concrete. Recently, it has increased the using of crushed aggregate for concrete due to the exhaustion of good natural aggregate. In case of Korea, the using ratio of crushed stone occupies about 97％ of whole coarse aggregate, and ratio of crushed sand occupies about 18.3％ of whole fine aggregate. This is an experimental study to compare and analyze the properties of crushed sand for concrete in capital region and concrete according to the replacement ratio of crushed sand to do suitable mix design and improve the concrete quality. According to results, it was found that nearly all the properties of crushed sand satisfied with the value recommended by KS.

• Tunnel and Underground Space
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• v.26 no.5
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• pp.418-430
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• 2016

In this study, experimental study on cement grout materials containing anti-washout admixtures or accelerators in grout column for reinforcement technology in groundwater-saturated mining cavity was conducted. As a result, the cement milk containing anti-washout admixtures was suitable for mixed aggregates, and the cement mortar containing anti-washout admixtures and the cement milk containing accelerators were suitable for crushed stone aggregate in terms of forming grout column. Especially, in the case of crushed stone aggregate injecting the cement milk containing accelerators, the diameter of the grout column was greatest and the void of the crushed stone aggregate was filled with grout materials. Therefore the case of crushed stone aggregate injecting the cement milk containing accelerators is considered for optimal grout materials and aggregate.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.969-978
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• 2010

In this study, a laboratory model test on utilization of recycled aggregates and crushed stone as vertical drains to use alternative material of sand in soft ground is performed. The vertical and horizontal coefficient of permeability of the recycled aggregates and crushed stone showed largely 1.2~4.0 times and 3.0~3.3 times greater than sand, respectively. Therefore, it showed enough to be an alternative material to the sand which had been being used as the vertical and horizontal drainage material before. The variations of pore water pressure with time showed constantly regardless of the load in all vertical drainage materials. When water level drops suddenly, the pore water pressure of the recycled aggregate and crushed aggregate is reduced to nearly zero. Therefore, it was applicable to the field because discharge capacity was similarity to that of sand. The settlement in crushed aggregates and recycled aggregate decreases gradually with the load increase. When water level drops suddenly, earth pressure in all drains materials was evaluated the equivalent drainage capacity similarity to sand because it show approaching the nearly zero.

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.3
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• pp.2342-2348
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• 1971

In concrete, the mater over aggregate is ever demanding each year in paralled with rapid development of Construction works from a couple of years ago. Want of most of them which is river gravel among aggregate has made us uneasy to get good gravel in quality. So far, we have counted on gravel, however, the time to turn the use of normal concrete into that of crushed concrete is closing at hand, I think. According to the results of study by Kaplan, Zeitman, Murdock, Hanada, Yamamodo, the shape of aggregate particle have a great effect on workability of concrete, as we know, is well known to the world. Crushed stone, particularly, is inconvenient to handle on account of jagged, angled particle form and rugged surface structure, give rise to inpediments in works, its unit water stands at about $15-20kg/m^3$, and w/c shows the increasing rate of approximately 5-10%, but it is unsuitable to use in terms of regidity. In order to research all of these, I have experimentalized and reviewed the physical character of aggregate and the regidity of concrete, in addition, its relative ratio of the elastic disposition as to gravel and crushed stone.

• Proceedings of the Korea Concrete Institute Conference
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• 1992.10a
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• pp.25-30
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• 1992

Since the first report on the damage of concrete structures due to alkali-aggregate reaction by T.E Stanton in 1940, cases of the damage are being reported in many countries. in the country, it is necessary to research the alkali-aggregate reaction of the crushed stone because of the short comings of natural aggregate and increasing needs of crushed stones. In this research, crushed stones from 63 local sites are collected and tested by ASTM C 289 chemical method.. The results show that most of the crushed stones are innocuous. However, the crushed stones from three sites are deleterious to the reaction by JIS A 5308. Petrographic and Mortar-Bar test will be carried out to find out any possibility of deleteriousness of the crushed stones

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.193-197
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• 2008

This study enforced to produce the planting concrete block which could be applied to various slopes economically. First of all, the physical properties was investigated with the various types of aggregate and aggregate ratio of the paste for the lead to mixture proportion of the planting concrete. As a result, the orchid stone as aggregate and 30% of aggregate ratio of the paste were used as the basic mixture proportion considering 20~30% of maintained void ratio for the growth of plant, over 20% of capillary suction for holding water, and 3MPa as the minimum strength. For the result of the test to the new planting block which was quite different from existing planting concrete block, it could complement the problems and be possible to produce effectively and economically because various slopes like 40ﾟ~75ﾟ, continual produce by extrusion, and pumping out were possible were possible.

• Magazine of the Korea Concrete Institute
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• v.7 no.3
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• pp.149-155
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• 1995

An experimental study was carried out to investigate the strength implovlng effect of stone dust in no fines concrete. The cement aggregate ratios of 1:6, 1:8 and 1:10 and several water-cemment ratios between 30% and 56% were chosen for the mix design of no-fines concrete. For the no-fines concrete with stone dust, the weight ratio of cement to stone dust 1:1 was adopted and super plasticizer, 1.5% of cement in weight, was used to obtain proper and workable state of concrete. The compressive and tensile strength test were performed and the results for the different mix designs were compared with each other. The results show that the compressive strength of no-fines concrete can be improved by 38% and the tensile strength by 17%~72% for the same w/c, when the same weight of stone dust as cement is mixed together.

• KCI Concrete Journal
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• v.14 no.3
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• pp.121-129
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• 2002

This study investigates experimentally into the design factors and quality variations having an effect on the properties of the combined high flowing concrete to be poured in the slurry wall of Inchon LNG in-ground receiving terminal. Especially, high belite cement and lime stone powder as cementitious materials and viscosity agent in order to improve self-compaction and hydration heat are used in this study. Water-cement ratio(W/C), fine aggregate volume ratio(Sr) and coarse aggregate volume ratio(Gv) as design factors of the combined high flowing concrete are applied to determine the optimum mix design proportion. Also quality variations for sensitivity test are selected items as followings. (1)Surface moisture(5cases) and (2)Fineness modulus of fine aggregate(5cases), (3)Concrete temperature(3cases), (4)Specific surface(3cases) and particle size of lime stone powder. As experimental results, water-cement ratio, fine and coarse aggregate volume ratio are shown as the optimum range 51%, 43% and 53% separately considering site condition of slurry wall. Also quality factors by sensitivity test should be controlled in the following ranges. (1) Surface moisture :to.67% and (2)Fineness modulus 2.6$\pm$0.2 of fine aggregate, (3)Concrete temperature l0-20t, (4) Specific surface 6,000$\textrm{cm}^2$/g and particle size 9.7$\pm$1.0${\mu}{\textrm}{m}$ of lime stone powder. Based on the results of this study, the optimum mix design proportion of the combined high flowing concrete are selected and poured successfully in the slurry wall of LNG in-ground tank.