• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.278-284
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• 1997

This study dealt with the flowing properties of the super flowing concrete for class F fly ash producted thermal power plant and the application for concrete industry. For this purpose, fly ash is analyzed for confined water ratio($\beta_p$)and the super flowing concrete is tested the flowing properties including flowing velocity, funneling time, height difference of box test and compressive strength. As the result, in order to satisfy the flowing properties of the super flowing concrete using class F fly ash, the optimum mixing conditions are determined water-bindrer ratio 37$\pm$2%, volume ratio of fine aggregates(Sr) 47$\pm$2% and coarse aggregates(Gv) 51$\pm$1%.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.329-334
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• 2001

In this paper, the crack properties of steel fiber reinforced concrete (SFRC) structures for environment by experimental and analytical methods are discussed. The major role played by the steel fiber occurs in the post-cracking zone, in which the fibers bridge across the cracked matrix. Because of its improved ability to break crack, SFRC has better crack properties than that of reinforced concrete (RC). Crack properties are influenced by longitudinal reinforcement ratio, volume and type of steel fiber, strength of concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.273-277
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• 1995

This study presents the physical and adhesive properties of the top coated materials for concrete slab. i.e, cement based top coated materials. epoxy mortar. The purpose of this study offers the investigation of construction factors to affect the quality of the coated materials over hardened concrete. The experimental results shows that the water content 3% of sand decline the strength and adhesive properties of epoxy mortar, on the other hand, dry surface and curing for cement based material.

• Fire Science and Engineering
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• v.2 no.1
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• pp.3-10
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• 1988

Concrete is incombustible and has good fire resisting properties, i. e. when exposed to fire it continues to perform satisfactorily for a reasonable period of time. Nevertheless, with time and high temperature gradient, brought about the fire, causes cracking and spatting. Further deterioration and loss of strength are caused by gradual dehydration of concrete paste. This paper is aimed to make a proposal for the design and construction of reinforced concrete structures with more sufficent resistance to fire by the theoritical analysis, which is base4 on investigation of general damages by the fire and change of properties on concrete influenced by high temperature.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.41-44
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• 1995

The purpose of this study is analyze to the properties of high fluidity concrete(W/C 35~50%) with the dosage of viscosity agent(Hydroxy Propyl Methyl Cellulose ; HPMC ; 15U), From the resuls, flowability was good about 200g/㎥. segregation-resisibility and placeability were good upward 300g/㎥, To synthetic, the dosage of viscosity agent are discovered best in 200~400g/㎥

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.11a
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• pp.63-66
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• 2002

In this study, it does a high volume flyash substituted concrete experiments in two curing temperature circumstances - 35$^{\circ}C$, 2$0^{\circ}C$. High volume flyash concrete is tested in fresh concrete properties and hardeded concrete properties. In the fresh concrete test items, there is slump, air contents, concrete setting tests. 3, 7, and 28 days water curing compressive strength is measured in the hardened concrete test. The purpose of this study is to submit a various flyash concrete data for application to field. The result of this study is that the best strength is developed at the plain concrete cured 2$0^{\circ}C$ and Mixing F43 shows the best strength among specimens which cured at 35$^{\circ}C$

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.52-56
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• 1996

In this study, when natural mineral with Silica components(Zeolite & Mudstone) abundant in Korea used as an admixture for concrete, it is investigated that the properties of strength increase and economic effect compared with Silica Fume, the general admixture of high strength concrete.

• Advances in concrete construction
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• v.13 no.6
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• pp.411-422
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• 2022

Aggregates mineralogical, and petrographic properties directly affect the mechanical properties of the produced high strength. This study is focused on the effects of magmatic, sedimentary, and metamorphic aggregates on the performance of high strength concrete. In this study, the effect of the mineralogical properties of aggregates on the compressive strength and modulus of elasticity of high-strength concrete was estimated by Artifical Neural Network (ANN). To estimate the compressive strength and elasticity modules, 96 test specimens were produced. After 28 days under suitable conditions, tests were carried out to determine the compressive strength and modulus of elasticity of the test specimens. This study also focused on the application of artificial neural networks (ANN) to predict the 28-day compressive strength and the modulus of elasticity of high-strength concrete. An ANN model is developed, trained, and tested by using the available test data obtained from the experimental studies. The ANN model is found to predict the modulus of elasticity, and 28 days compressive strength of high strength concrete well, within the ranges of the input parameters. These comparisons show that ANNs have a strong potential to predict the compressive strength and modulus of elasticity of high-strength concrete over the range of input parameters considered.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.365-372
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• 1997

This study is aimed for manufacturing a High performance Concrete(HPC) Pile as using steel fibers, investigation the mechanical properties of HPC Pile and proposition the potential application. At this study. We found that mechanical properties(cracking moment and fracture moment) of Pretensioned spun High strength Concrete (PHC) Pile using steel fibers is much superior to without steel fibers. Therefore. we think that using steel fibers in Concrete Pile is to progress flexural strength energy absorption capacity and post-cracking resistance.

• 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.