• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.489-494
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• 2001

Several studies have reported that Granulated Blast-Furnace Slag improved the properties of concrete. The Granulated Blast-Furnace Slag could be a good alternative in the shortage of aggregate situation. Slag shows the possibility of influential aggregate and effect of environment preservation. This study presents that the basic properties of fresh concrete using Air-cooled Blast-furnace slag aggregate and Water-cooled Blast-furnace slag aggregate. Testing Factors of this study are concrete slump, slump loss, bleeding, and air contents. The result of this study is below. 1) In case of proportion slag and grave is 50 to 50, the biggest slump value is measured. 2) In the concrete using of air-cooled Blast-furnace slag aggregate, the bleeding capacity is a little. In the concrete using of Water-cooled Blast-furnace slag aggregate, the bleeding capacity goes up to 50% increase. 3) As substitution rate of the granulated blast-furnace slag goes up, air content is increased.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.89-92
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• 2005

This study investigates influence of particle properties of crushed sand on the duality of concrete. The test shows that an increase of fineness modulus(FM) resulted in high slump and air contents, while compressive strength decreased due to decreased adhesion with reduction of surface area. As grain shape become rounder, the slump of concrete increased, due to reduction of internal friction, and increased air contents. The reduction of adhesion by abrasion of surface declined compressive strength during the process of manufacturing crushed sand. Increase of powder contents decreased slump and it also decreased air contents due to the effect of filling air void. In addition. using powder contents increased compressive strength, but could not find any difference of bleeding and tensile strength with particle properties.

• Journal of Ocean Engineering and Technology
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• v.14 no.3
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• pp.66-71
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• 2000

The main objectives of this study are to carried out in order to evaluate strength development of Fly Ash concrete containing various amounts of Fly Ash such as 0%, 10%, 20% and 30%. The experimental variables included in this test program consist of content of Fly Ash, concrete strength and chemical activation. As Fly Ash increases, air content, strength development of concrete and slump loss of normal strength concrete were gradually decreased. The inclusion of Na$_2$SO$_4$increased the short-term strength of concrete that contains Fly Ash. In addition, the strength development of concrete that contains Fly Ash and Na$_2$SO$_4$were improved.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.27-30
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• 2003

This study is investigated the various properties and drying shrinkage of concrete according to water content under the condition proper fluidity is adjusted, in order to suggest the method for reduction of crack by drying shrinkage. According to the results, though water content varies, slump and air content are satisfied to the planed values, but shear slump and separation happen at water content of 120 and 140kg/$m^3$ due to the overuse of superplasticizer(SP). As water content is diminished, setting time is retarded by an increase of the using amount of SP, and compressive and tensile strength increase in the range of 160-180kg/㎥ of water content, but decrease significantly at 120 and 140kg/$m^3$. Length change by drying shrinkage decrease with a decrease of water content. Therefore, considering not only drying shrinkage but also fluidity, setting time and strength, it proves that the most appropriate water content of concrete is 160kg/$m^3$ in the condition of this experiment.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.707-714
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• 2001

This paper presents the fundamental study on rational manu(acture of Very High Strength(VHS) concrete using industrial by-products as like silica fume, slag and fly ash. In this study, we had tested various mixing cases to manufacture the VHS concrete(target compressive strength : over 1,000 kgf/$cm^{2}$) which is easily workable (target slump flow : 60$\pm$l0cm), The main variables studied are; 1) test variables to find the optimum replacement ratio of mineral admixture, 2) test variables to find a rational water-binder ratio, a proper binder content, 3) test variables to find the method for reduction of slump loss, 4) test variables to know the influence of air entrainment on frost resistance. From the test results, it is concluded that the rational mix design can be made by using 40% slag, 10% silica fume, and water reducing agent(slump loss reduction type). We found that it is unnecessary to entrain air for freeze-thawing resistance.

• Journal of the Korea Concrete Institute
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• v.12 no.5
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• pp.93-99
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• 2000

The physical properties of freshly mixed steel fiber reinforced recycled concrete(SFRRC) were_investigated. Physical state and quality of fresh concrete were monitored batch by batch. the properties of freshly mixed SFRRC were determined in terms of slump, air content, superplasticizer, and bleeding ratio. Concrete mixtures were produced for three kinds of aggregate proportions. So, the experimental variables are various aggregate proportions, steel fiber contents(0, 0.5, 1.0, 1.5%) and steel length(30, 50, 60mm). From experimental results, optimum s/a by various experimental variables, variations of the slump by the air contents, and optimum superplasticizer to decrease unit water were presented.

• Journal of the Korean Society of Industry Convergence
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• v.5 no.3
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• pp.225-232
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• 2002

The purpose of this study is to find the mechanical properties of lightweight concrete using expanded clay. Thus, slump, air content, compressive strength, elastic modulus, tensile strength, length change ratio, unitweight change ratio and absorption of lightweight concrete have been investigated. The conclusions of this study are as follows ; 1. The loss of slump and air content of concrete increased as the expanded clay content increased and the size of coarse aggregate decreased. 2. The compressive strength of concrete using 100% expanded clay of 13, 19mm size at 28 days were respectively 282, $252kgf/cm^2$. 3. The elastic modulus and tensile strength of concrete decreased with increase of expanded clay content. 4. The length change ratio of concrete increased with the larger coarse aggregate size, and decreased with the increase of expanded clay content. 5. The unit weight of concrete decreased with the increase of expanded clay content, and the ratio of that was larger at the early age.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.177-178
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• 2023

In this study, the mass production process was simulated using a 1m³ batcher plant to evaluate the application of high-strength fire resistance concrete. The strength ranges of concrete were set to 50, 60, 70, and 80 MPa, and each concrete mix proportions was selected through preliminary experiments in the laboratory. For the selected concrete mix proportions, after the mixer load value was stabilized in the batcher plant, the slump flow and air content of the fresh concrete were evaluated, and the compressive strength was evaluated up to 56 days. As a result of the experiment, both the slump flow and air content of the fresh concrete satisfied the target performance, and in the case of compressive strength, 50 and 60 MPa satisfied the target performance at 28 days and 70 and 80 MPa at 56 days.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.23-26
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• 2003

Metakaolin is a cementitious material for producing high-strength concrete. This material is now used as substitute for silica-fume. In this paper, we studied the properties of fresh concrete such as slump-flow, air content, and the feature of strength of hardened concrete according to the substitute ratio of metakaolin, silica-fume. In the fresh concrete test, the time depend loss of slump-flow & air content is good to 10-15% substitute ratio of metakaolin. And, in the strength test, 10-15% substitute ratio of metakaolin is good for producing high-strength concrete also. But, allowing for economical efficiency, we concluded that 10% is a adequate substitute ratio for producing high performance concrete.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.3
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• pp.123-128
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• 2013

This study was performed to evaluate the slump flow, air content, setting time, compressive strength, adiabatic temperature rise and diffusion coefficient of chloride used ordinary portland cement, crushed coarse aggregate, crushed sand, river sand, fly ash, limestone powder, blast furnace slag powder and superplasticizer to find optimum mix design of low carbon green concrete for structures. The performances of low carbon green concrete used fly ash, limestone powder and blast furnace slag powder were remarkably improved. This fact is expected to have economical effects in the manufacture of low carbon green concrete for structures. Accordingly, the fly ash, limestone powder and blast furnace slag powder can be used for low carbon green concrete material.