• Journal of the Korea Concrete Institute
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• v.12 no.6
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• pp.109-117
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• 2000

CFRD(Concrete Faced Rockfill Dam) face slab concrete has a much capability to occur crack due to drying shrinkage, plastic shrinkage and bad compaction etc. Because of these cracks of concrete induce structural problem and decrease durability of dam, it is need to reduce crack of face slab concrete. This is an experimental study to analyze the influence factors on crack properties of CFRD face slab concrete. For this purpose, various mix proportion of CFRD face slab concrete and concrete using PPF(polypropylene fiber0 and fly ash was selected. And tests for drying shrinkage, bonding strength, water permeability and plastic shrinkage were performed, and then CFRD D and PPC of those mix proportion were placed in CFRD field. According to test results, it was found that the bonding strength of C1(compact sufficiently) was higher about 10~20% than that of C2(compact insufficiently). And the engineering properties of PPC(concrete using PPF) and FAC(concrete using fly ash) were better than those of the others ; the permeability of PPC and FAC after 8 weeks curing was little lower than that of CFRD D, and plastic shrinkage crack of PPC and FAC was lower 40~60% than crack of CFRD D.

• Journal of the Korea Institute of Building Construction
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• v.2 no.4
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• pp.145-152
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• 2002

High fluid concrete unlike OPC concrete is made with various material, and the phase of fresh concrete is considerably different. In order to understand fluidity phase and mix properties of high fluid concrete, concrete is required to access as suspension structure which consists of aggregate and paste. The focus of this paper is to analyze the test results and quantify the effect of mix proportions of mortar and fineness modulus of sand on the properties of fresh mortar. The effect of water-binder ratio. sand-binder ration. contents of ggbs (by mass of total cementitious materials). and various contents of water reducing agent on the yield stress and plastic viscosity of the mix is studied. Based on the experimental results, the fellowing conclusions can be drawn: (1) The mixing time needed for high fluid mortar was approximately two times more than that of ordinary portland mortar. (2) The fluidity phase of mortar could be explained by yield stress of mix and the fluidity of mortar. (3) As the content of ggbs increased, yield stress of mortar was decreased and plastic viscosity of it was increased. (4) For the high fluid mortar, it was appeared that sand-binder ratio should be below 1.5.

• 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.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.341-344
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• 2008

Lightweight concrete is known for its advantage of reducing the self-weight of the structures, reducing the areas of sectional members as well as making the construction convenient. Thus the construction cost can be saved when applied to structures such as long-span bridge and high rise building. However, the lightweight concrete requires specific mix design method that is quite different from the typical concrete, since using the typical mix method would give rise the material segregation as well as lower the strength by the reduced weight of the aggregate. In order to avoid such problems, it is recommended to apply the mix design method of self-consolidating concrete for the lightweight concrete. Therefore experimental tests were performed as such mechanical properties(compressive strength, dry density and structural efficiency) of concrete and dry shrinkage according to ACI committee 209.

• 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 $13.5^{\circ}C$.

• Computers and Concrete
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• v.19 no.6
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• pp.737-744
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• 2017

Geopolymer Concrete is typically proportioned with activator solution leading to moderately high material cost. Such cost can be enduring in high value added applications especially when cost savings can be recognized in terms of reduction in size of the members. Proper material selection and mix proportioning can diminish the material cost. In the present investigation, a total of 27 mixes were arrived considering the mix parameters as liquid-binder ratio, slag content and sodium hydroxide concentration to study the mechanical properties of geopolymer concrete (GPC) mixes such as compressive strength, split tensile strength and flexural strength. The derived statistical Response Surface Methodology is beleaguered to develop cost effective GPC mixes. The estimated responses are not likely to contrast in linear mode with selected variables; a plan was selected to enable the model of any response in a quadratic manner. The results reveals that a fair correlation between the experimental and the predicted strengths.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.209-210
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• 2011

This study is aimed to draw a optimum combined fiber mix condition to improve spalling resistance and flowability of ultra high-strength concrete. As a result, W/B 12.5% concrete specimens were prevented spalling with PE0.05+ PP0.1, PE0.05+NY0.1 and W/B 12.5% concrete specimens were prevented spalling with all of combined organic fiber mix condition. But There is no significant influence of steel fiber under 5% volume ratios to prevent spalling. In the scope of this study, we suggest that condition of optimum volume ratio PE0.05+NY0.1 is to improve spalling resistance, flowability and residual compressive strength.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.363-368
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• 1997

In this study, permeable polymer concretes using unsaturated polyester (UP) resin with binder contents of 6, 7 and 8%, filler-binder ratios of 0, 0.5, 1.0%, and various sand and aggregate contents are prepared, and tested for compressive and flexural strengths, length change and water permeability. The effects of the mix proportioning factors on the strength properties, length change and coefficient of permeability of the permeable polymer concrete are discussed. From the test results, increase in the compressive strength and decrease in the coefficient of permeability of permeable polymer concrete are clearly observed with increasing filler-binder ratio. The permeable polymer concretes having a compressive strength of 9.4~28.3MPa and a coefficient of permeability of 0.12~1.93 cm/s can be produced in the consideration of the mix proportioning factors.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.185-188
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• 2005

This study selected three different specified concrete strength types of mixture which were applied to domestic seawater concrete structure and measured compressive strength and chloride diffusion coefficient and composed the formula of prediction model of chloride diffusion coefficient in order to provide the useful data for concrete mix decision of seawater structures. As a result, the formula of prediction model of chloride diffusion coefficient which set W/C and compressive strength as parameters and performed multiplex regression analysis which was based on the mathematical theory was confirmed more reliable than the formula of prediction which was composed existing water-cement ratio function.

• Resources Recycling
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• v.22 no.3
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• pp.18-27
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• 2013

In this study, it was developed eco-friendly mix design of mine sprayed concrete, which satisfies both the stability and economics by mixing the industrial in cement, for development of the mine sprayed concrete and recycling of industrial. From this research, it is found that mixing of mineral admixture is effective on strength enhancement. Also, it is considered that designed mixing ratio of sprayed concrete using industrial byproducts should be applied to the field through field test.