• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.251-252
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• 2009

Rheological characteristics of flowable concrete manufactured in domestic products of cement, aggregates, and SP admixtures were investigated by experiments and the predictive model of rheological characteristics of flowable concrete has been newly proposed considering with the effects of the W/C ratio and the dosage of SP admixture.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.379-382
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• 2000

In this paper, we evaluated the suitability of converter slag as concrete aggregate by measuring physical and chemical characteristics of converter slag. The converter slag mainly contains SiO₂and CaO as the chemical composition. The reaction with water and a little of free CaO in the slag causes slag's volume to expanse. Therefore, we used several aging method in order to decrease the characteristics of slag volume expansion. Then the compressive strength of concrete with the converter slag aggregate is measured.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.132-137
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• 1993

The purpose of this study is to evaluate the quality characteristics of concrete using super plasticizer which is on the market within the country. For this purpose, nine kinds of super plasticizer are compared and analyzed for the slump , air content, unit weight, water-reducing percent and ratios of compressive strength with admixture content. As a result, the optimum quantity of admixture content were obtaining for ordinary and high strength concrete using super plasticizer.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.247-253
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• 1997

This study performed the experimental research comparing mechanical characteristics of the concrete replaced by the waste glass powder with the non-replaced concrete. The experimental parameters are kinds of the waste glass powder and replacement rate of the waste glass powder on the cement. As as result, the slump value, the flow value and the amount of air were decreased as the waste glass powder replacement rate increased, and the strength was increased when the waste glass powder replacement rate is 5%~15%.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.31-36
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• 1996

Various strength characteristics of recycled concretes containing different contents of recycled aggregates from waste concretes were compared with one another. Five different contents. 0%, 50%, 60%, 70% and 80%, of recycled concrete were used for this study. Study results showed that the compressive strength, flexural strength, tensile strength, elastic modulus and fracture toughness varied with contents of recycled aggregates. Target strength of the recycled concrete could be difined by nonparametric regression model as a funcion of content of recycled aggregate in the mix.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.140-147
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• 1996

This study was performed to investigate the characteristics of workability and strength of the concrete containing admixtures such as silica fume, fly ash, blast furnace slag, and rice husk ash. For this purpose, the workability and the strength of the concrete containing each admixture were tested and analyzed according to the unit weight of binder and the replacement ratio of each admixture.

• Magazine of the Korea Concrete Institute
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• v.9 no.1
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• pp.173-181
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• 1997

The objective of this study is to obtain the mechanical characteristics of prefoarmed lightweight foamed concrete using the polymer ham agent which has high lightness. flowability and strength. For this purpose, the prefoarmed lightweight foamed concrete which was developed to have flow value over 180mm. unit weight between 0.38t/$m^3$ and 0.64t/$m^3$, and compressive strength about 30kg/$cm^2$ was used. This paper presents extensive test data on Young's modulus. Poisson's ratio, stress-strain curve, the characteristics of strength of the foamed concrete and also presents the mechanical characteristics of the foamed concrete with different foam sizes. It is expected that this study provides an importance guide to design and manufacture lightweight foam concrete, so that it helps to expand its structural use.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.673-678
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• 2002

There are various methods for the electrochemical techniques to estimate diffusion coefficient of chloride ions in concrete, such as ASTM C 1202 test method, Andrade's method, Dhir's method, Tang's method, and etc. In the case of estimating diffusion coefficient of chloride ions in concrete by using these methods, applied voltage and resistivity nay exercise some influence on the characteristics of chloride ions diffusion. Thus. in this study, effect of applied voltage and resistivity on the characteristics of chloride ions diffusion in concrete were researched by applying voltage in 12V, 30V, and 60V, and by using resistivity in 0.2Ω and 1.0Ω, respectively. It can be concluded that diffusion coefficient of chloride ions are found to be increasing as the individual applied voltage and resistivity decrease, when water-cement ratio is constant.

• Advances in concrete construction
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• v.6 no.4
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• pp.375-386
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• 2018

This experimental work aims at developing and investigating a lightened concrete by the addition of treated straws. The used formulation is based on that of an ordinary concrete which is composed of sand and gravel as the main aggregates. The properties of the straws are improved by using one of two treatments before their use: the hot water and bitumen. Henceforth, the main objective of this study is to assess the mechanical characteristics of different formulations with different compositions and treatments on straws. The obtained results have shown that the addition of straws improves its lightness property. However, it decreases the compressive and flexural strengths as well as decreases the modulus of elasticity and increases the dimensional variations. Set into comparison to the concrete with untreated straws, the treatment of straws by hot water or by bitumen improves most of the characteristics.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.04a
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• pp.201-206
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• 1993

As the vibration loads are variable and the design criteria are more strict, in this study, the dynamic characteristics of the slab is analyzed and the and the vibration is controlled for the special peculiarity of structures. First, the procedure of dynamic analysis is developed by the finite element method and then examined by using the slab model tests. Second, in order to improve the dynamic characteristics, the effects of the number of supports, material properties, position of exciting force, added mass and dynamic balance on the dynamic behavior of reinforced concrete slabs are analysed. It is concluded that the vibration can be controlled by the change in the natural frequency of system and the use of the high-strength concrete or polymer impregnated concrete (PIC), and the dynamic characteristics can be considerably affected by the arrangement of equipments, added mass, and dynamic balance, etc.