• Journal of Industrial Technology
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• v.17
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• pp.313-322
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• 1997

As the weight of trucks increases, the need for concrete pavement also increases. Therefore, the addition of fly-ash may improve the properties of pavement concrete as well as recycle fly-ash. A full factorial experiment was performed using the primary variables, such as water-cement ratio, fly-ash substitution ratio, and maximum size of coarse aggregate, as a preliminary study for optimum mixture design for pavement concrete. The results of preliminary study indicates that the addition of fly-ash is the most important factor determining concrete strength, followed by the maximum size of coarse aggregate and water-cement ratio. It, also, shows the relative importance of fly-ash substitution ratio, compared to the water-cement ratio, and the interaction effects between the primary variables. Optimum mixture designs for pavement concrete incorporating fly-ash, that satisfied the target responses, were proposed in terms of fly-ash substitution ratio, water cement ratio and maximum size of coarse aggregate.

• Journal of Ocean Engineering and Technology
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• v.15 no.3
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• pp.128-133
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• 2001

It is generally known that the concrete structure subjected to severe environment is much affected by the corrosion of reinforcement, the freezing and thawing action of concrete structure. The main objective of this study is to investigate the freezing and thawing resistance of concrete including fly ash. The effect of the air content in concrete using fly ash is investigated. The experimental study is conducted for 10 mix-ratio cases of concrete of which variables are content of fly ash, concrete compressive strength and containment of air-entrained admixtures. Test results show that the freezing and thawing resistance improves as the amounts of fly ash increase, and concrete with air-entrained admixtures has good freezing and thawing resistance. The concrete with fly ash is to be included air-entrained admixture according to content of fly ash in order to increase the freezing and thawing resistance.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10c
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• pp.133-138
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• 1998

The purpose of this study is to offer basic information of fly ash concrete for field application. Through before study and fly ash in mortar, various properties as fly ash ratio in concrete were checked according to the experimental result, slump was increased and entrained air quantity was decreased as fly ash ratio is increased in fresh concrete. In hardened concrete, strength development of plain concrete(W/B 50%) was slower than water-reduced concrete(W/B 40%) at early age. Especially water-reduced concrete was remarkabily faster than no fly ash in concrete. Moduls of stastic elasticity and stress-strain relationship of fly ash in concrete nearly were effect on no fly ash concrete.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.3
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• pp.122-135
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• 2002

Although fly ash possesses viable engineering properties, an overwhelming majority of fly ash from coal combustion is still placed in storage or disposal sites. Similarly, sludges generated from various water treatment operations are predominantly subjected to the fate of land disposal. To prepare sludges fur land disposal typically requires time consuming dewatering schemes, which can become extremely difficult to execute depending upon the composition of the sludge and its affinity for water. This study was undertaken to reuse fly ash and sludge as construction materials. This paper includes geotechnical properties of fly ash and fly ash-lime-sludge mixture and results of compaction test, UU-test, falling head test, leaching test and CBR test. The effect on mixing fly ash with sludge and lime and the effect of curing period and the results are obtained from this test.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.147-152
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• 1999

The purpose of this study is to offer foundmental information of fly ash concrete for field application. Through before study of fly ash concrete, various properties were checked. but when fly ash was added In concrete, entrained air quantity was decreased as fly ash substitution is increased in fresh concrete. so entrained air(below AE) quantity and a kind of AE according to fly ash substitution was tested basic properties. Also water-reducing efficiency was tested. And hydration heat according to fly ash substitution was tested by KR-100. As result of test, according to fly ash substitution increase, entrained air quantity is increase for target entrained air quantity, water-reducing efficiency and hydration heat are positive.

• Journal of the Korea Concrete Institute
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• v.12 no.3
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• pp.87-94
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• 2000

Disposal of casting foundry fly ash generally depends on reclamation up to the present. This is the great loss from a standpoint of saving resources and utilizing industrial wastes. Therefore, a study on the reuse of fly ash as a substitute material for construction is necessary in order to utilize industrial wastes, to reduce cost and improve quality in producing concrete products, and to protect environment from pollution. In this study, methods for the reuse of the casting foundry fly ash, industrial wastes products, as an admixture for concrete are discussed. For this purpose, fly ash was extracted from casting foundry and tests of physical and chemical properties are executed. Also, various characteristics of concrete using fly ash as an admixture are experimented. Finally, the reuse methods for casting foundry fly ash are presented.

• 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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• 1990.10a
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• pp.125-130
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• 1990

Fly Ash in concrete is known to be effective in improving workability, the reduction of heat of hydration, increasing the long-term compressive strength, and improving durability. Recently, fly ash is consedered an essential material for the high-strength concrete. In this paper, investigations for the strength and workability characteristics was carried out when fly ash was used in the high-strength concrete. As the result, fly ash was effective in increasing the long-term compressive strength, but the short-term compressive strength was gradually decreased with increating fly ash contents. And also the use of superplasticzers was required for providing the proper workability when fly ash contents were increased. The optimum content of fly ash was about 10%.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2001.11a
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• pp.82-87
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• 2001

The purpose of this study is for the active use of the fly ash, which is a by-product of the combustion pulverizes coal thermal power plants, to compensate for the lack of landfill and for conservation of energy, by using fly ash as the supplementary cementitious material, and to prove its possibility as the related products of the cement. First of all, the ordinary fly ash is grinded in a special method and its fineness is controlled from 6000$\textrm{cm}^2$/g to 8000$\textrm{cm}^2$/g, then replaced it with the 10% to 80% of the cement mortar in order to test physics characteristics. The first experiment conducts on the strength development in fly ash replacing content and fineness. and the changes of the flow values, incorporating fly ash into cement. The second one is about the slow development of the strength of the fly ash mortar in early ages, and improves its strength with the activator $Na_{2}SO_{4}$, using high volume fly ash.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1996.04a
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• pp.88-96
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• 1996

The characteristic analysis of fly ash generated from a fired power plant using bunker-C oil has been investigated. Ash size distribution by an optical microscopy with image processing technique, morphological shape by a scanning electron microscope(SEM) and microscope, chemical composition by the inductively coupled plasma emission spectrometry(ICP), and resistivity measurement as a function of temperature and moisture content by the resistivity meter are performed. A study of physical, chemical and electrical characteristics of bunker-C fly ash plays an important role of improving the performance of an electrostatic precipitator and protecting air pollution. The samples of bunker-C fly ash for analysis were collected from the electrostatic precipitator hopper of Ulsan Power Plant Unit 1 and Pusan Power Plant Unit 1. Mass median diameter(MMD) of bunker-C fly ash was measured 12.7${\mu}{\textrm}{m}$, while MMD of fly ash generated from the mixture of bunker-C oil(40%) and domestic anthracitic coal(60%) was 25.7${\mu}{\textrm}{m}$. The morphological structure of bunker-C fly ash consisted of fine particles of non-spherical shape. The primary chemical components of bunker-C fly ash were composed of SiO2(2.36%), Al2O3(4.91%), Fe2O3(14.33%) and C(11.84%). Resistivity of bunker-C fly ash was found to be increased with increasing temperature at the range of 100~15$0^{\circ}C$ and was measured 103~104 ohm-cm.