• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.2
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• pp.191-198
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• 1999

The purpose of this study is investigating characteristics of the concrete containing Fly-ash according to different 4 mix design, that is, the first mix design is partial replace Fly-ash of cement, second is partial replace Fly-ash of cement and fine aggregate, third is partial replace Fly-ash of fine aggregate, fourth partial replacement of fine and coarse aggregate. For this purpose, selected test variables were water-binder ratio with two levels of 45%, 50%, and Fly-ash contents with four levels 0%, 10%, 20%, 30%, As the result of this study are as follow. 1) The result of mix design of a partial replacement of cement, the slump-flow value was appeared a promotive effect of viscosity. But in case of the over with Fly-ash 10% and the other mix design was not changed slump value. 2) The unit weight of the mixing rate with Fly-ash 0% was $1.875{\sim}1.884t/m^3$, the other mix design 10% over with Fly-ash was $1.846{\sim}1.615t/m^3$, the difference was appeared less about 15% than that. 3) In design, partial replace Fly-ash of fine aggregate, this compressive strength was appeared that the concrete age after 7 days was higher than in partial replacement of cement, therefore, the default of a concrete with Fly-ash, that is the earlier compressive strength was to lessen, was improved. 4) The thermal conductivity of the all mix design was $0.447{\sim}1.144kcal/mh^{\circ}C$, this value was as good as a lightweight aggregate concrete.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.205-211
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• 2006

The purpose of this study was to evaluate the effects of fly-ash on strength development and durability of latex-modified concrete (LMC) and ordinary portland cement concrete (OPC). Main experimental variables were latex contents (0%, 10%, 15%) and fly-ash content (0, 10%, 20%, 30%). Air content and slump tests were performed to check the basic properties of fresh concretes, and compressive strength, flexural strength, rapid chloride ion permeability and chemical resistance were measured to analyze the basic properties of hardened concretes. The test results showed that air contents of LMC with fly ash decreased as fly-ash contents increased from 0% to 30%. Compressive and flexural strength developments of LMC with fly ash were quite similar to those of LMC without fly ash. However, the long-term flexural strength development of LMC with fly ash after 90 days were bigger than that of LMC without fly ash. Chloride ion permeability and chemical resistance decreased rapidly as the content of fly ash increased. Thus, fly ash could be used at LMC in order to reduce water permeability.

• Journal of the Korean Ceramic Society
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• v.41 no.11
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• pp.834-841
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• 2004

The purpose of this study is to investigate the properties of traditional Korean ash glazes by using locally available sources; 10 kinds of grain stems,2 kinds of husks (pod, chaff), and 4 kinds of vegetables (spinach, radish leaf and stem, pumpkin leaf and stem, pepper stem), and to develop their practical uses as ash glazes. The test results of these ash glazes indicate that these ashes can be classified into four categories. The first group, which includes perilla stem ash, sesame stem ash, black bean stem ash and red-bean stem ash, shows strong milky white due to relatively lower content of $SiO_2$, and relatively higher content of CaO and P$_2$O$\_$5/ content (10% higher than others), and their glazes were found to be suitable for opaque glaze as they show relatively stable bright greenish color. The second group includes pepper stem ash, spinach ash, pod ash, radish leaf and stem ash, and bean stem ash, and this group was found to contain even quantity of every component. And their glaze show somewhat greenish color because of especially high content of MgO and more than 2% of Fe$_2$ $O_3$. They were found to be suitable for basic glaze of IRABO glaze. The third group, which includes com stalk ash, white bean ash, pumpkin leaf and stem ash, has more $SiO_2$ and Al$_2$ $O_3$ than other ashes, and it also contains 3～5% of Fe$_2$ $O_3$. As a result of those components, this third group shows the greatest change of color and chroma, and was found to be suitable glazes as basic glaze of Temmoku and black glazes. The fourth group (reed ash, rice straw ash, indian millet stalk ash and chaff ash) has as much as 45～82% of $SiO_2$ and relatively lower content of Fe$_2$ $O_3$ and P$_2$ $O_3$. This group shows blue or greenish white color, and was found to be suitable as the basic glaze of white glaze.

• The Journal of Engineering Geology
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• v.20 no.3
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• pp.297-310
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• 2010

This study represents basic research into the utilization of mixed ash (fly ash and bottom ash) from the ash pond of the Taean Thermal Power Plant as a construction material. We conducted physical and mechanical experiments on the mixed ash and examined its engineering characteristics in terms of its use as a material for road landfill and structure backfill. We evaluated the physical and chemical characteristics of the ash by performing tests to determine specific gravity, maximum and minimum density, liquid limit and plastic limit, grain size distribution, composition (by X-ray diffraction), and loss on ignition. We also evaluated the mechanical characteristics by testing for permeability, compaction, CBR, and tri-axial compression. The experiments on the mixed ash yielded a specific gravity of 2.18-2.20, dry density of $9.38-13.32\;kN/m^3$, modified CBR of 16.5%-21%, permeability coefficient of 1.32 to $1.89-10^{-4}cm/sec$, and drained friction angle of $36.43^{\circ}-41.39^{\circ}$. The physical and mechanical properties of the mixed ash do not meet the quality standards stipulated for road landfill and structure backfill materials. Mixed ash with a high content of fly ash failed to meet some of the quality standards. Therefore, in order to utilize the mixed ash as a material for road landfill and structure backfill, it is necessary to improve its properties by mixing with bottom ash.

• Journal of the Korean GEO-environmental Society
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• v.15 no.11
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• pp.61-66
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• 2014

The various recycling methods of mixed coal ash have been developed considerably and it's recycling quantity has been increased. However, the more relatively finer grain content of coal ash in ash pond is increased the more it's quantity is increased in recycling as products for drainage in soft ground etc. Accordingly, the geotechnical properties of mixed coal ash in ash pond would be inferior and it's recycling rate should reach the limitations in increase. In this study, to recycle mixed coal ash contained fine grain in considerably amount as products for strength, etc. By adding binder to it and manifesting, it's compressive strength is stronger than the criteria, these are suggested; 1) the variety of compressive strength test performed on mixed coal ash of various grain distributions as main material, 2) the kind of binder, it's mixing quantity and the optimum content rate range of fine grain coal ash that the compressive strength stronger than a certain compressive strength is manifested. Cement is more excellent than quicklime as binder in manifesting stronger compressive strength and the sieve type to sort it is #40 sieve in order to recycle all mixed coal ash in ash pond efficiently as products for drainage as well as products for strength, etc. And, it could increase insufficient compressive strength remarkably that content of pure sand is more in the rate as pure sand and the part of mixed coal ash in ash pond to pass through #40 sieve is mixed in the ratio of 2 to 8.

• Journal of the Korean Ceramic Society
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• v.39 no.2
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• pp.126-134
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• 2002

Fabrication of mortar containing fly ash for high strength structural material was investigated by using a Mechanochemically Processed Cement (MPC) and/or Fly Ash (MPFA), which was compared to the specimen (at the same fabrication condition of fly ash adding contents (10, 20 and 30 wt%) and curing time (7 and 28 days)) fabricated by using Ball-mill Processed Cement (BPC) and As Received Fly Ash (ARFA) in terms with compressive strength and microstructures. Mortar specimen fabricated by using MPC and ARFA showed 5-11% higher compressive strength than that in the case of using BPC and ARFA, and mortar specimen by using BPC and MPFA represented 10-20% higher compressive strength than that for the case of using BPC and ARFA. Furthermore, mortar specimen fabricated by simultaneously using MPC and MPFA exhibited about 24% higher value of compressive strength than that for the case of using BPC and ARFA, which was considered to be synergic efficiency in increasing compressive strength. Increased compressive strength as above mentioned is considered to be caused by mutually increased affinity between cement and fly ash induced during mechanochemical Processing(MP).

• Journal of the Korean Ceramic Society
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• v.39 no.2
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• pp.135-144
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• 2002

Fabrication of high strength structural concrete was investigated by using a mechanochemically Surface Treated Fly Ash(MSTFA) induced by mechanochemical processing through ball-milling of (90 wt% As Recevied Fly Ash(ARFA) + 10wt% cement) mixture, which was compared to the specimen fabricated by using As Received Fly Ash(ARFA) in terms with compressive strength and microstructures. The compressive strength of concrete specimen fabricated by using MSTFA represented 10-20% and 2-7% higher value than that for the case of using ARFA and BPFA in each cases. Increased compressive strength as above mentioned is considered to be caused by mutually increased affinity generated between cement and fly ash during mechanochemical processing.

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.1
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• pp.81-88
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• 2005

The fly ash has been widely used in the latest to complement the performance and economical efficiency of the concrete which uses only a normal portland cement, the pulp ash gained through the incineration of paper sludge is possible to be used as the material of concrete because it contains the properties similar to the previous fly ash in ingredients and physical characteristics. Therefore, this research has tested physical characteristics by replacing 20% of fly ash used with the paper ash to solve the problem which lowers the early strength caused when the fly ash was used. As a result, it showed that the fluidity becomes lower and the compressive strength becomes increased by using paper ash. In addition, after mixing the paper ash with the fly ash, it showed that time and heating amount of the 2nd peak of the minor heat of hydration affecting the revelation of strength was equivalent to the combination for normal portland cement, and also indicated that the compressive strength for 3 days is superior to the combination of the fly ash. Therefore, if the paper ash having a regular fineness is used, it was effective in improving the early strength of concrete used the fly ash.

• Resources Recycling
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• v.13 no.2
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• pp.16-23
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• 2004

To increase the recycling rate of anthracite fly ash, the properties of anthracite fly ash were compared to that of bituminous fly ash. Especially, the high temperature properties of the fly ash are investigated by using thermal analysis, high temperature microscope and X-ray diffraction analysis for utilizing anthracite fly ash to prepare the calcinated bricks. The average ratio of $A1_2$$O_3$/$SiO_2$ for anthracite is 0.62 and the ratio for bituminous is 0.34. The content of $SiO_2$ in anthracite fly ash was higher than that of bituminous fly ash. The $A1_2$$O_3$ of anthracite fly ash reacted with the $A1_2$$O_3$ in the fly ash and formed new mullite crystal at over $1000^{\circ}C$, so anthracite fly ash showed high fire resistance. And, the fly ash mixtures having kaolin were prepared, and then extruded in vacuum to evaluate the extruding property of anthracite fly ash mixture. The extruding velocity was decrease with increasing the addition amount of fly ash in the mixture, and the maximum addition amount of fly ash that could be extruded was 60 wt%.

• Journal of Ocean Engineering and Technology
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• v.23 no.3
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• pp.20-29
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• 2009

This study investigated the shear strength characteristics of waste tire powder-added lightweight soil (WTLS), which were developed to recycle dredged soil, bottom ash, and waste tires. The WTLS used in this experiment consisted of dredged soil, bottom ash, waste tire powder, and cement. Test specimens were prepared with various contents of waste tire powder ranging from 0% to 100% at 25% intervals and bottom ash contents of 0% or 100% by the weight of the dry dredged soil. In this study several series of direct shear tests were carried out, which indicated that the shear properties of WTLS were strongly influenced by the mixing conditions, such as the waste tire powder content and bottom ash content. The unit weight, as well as the shear strength of the WTLS, decreased with an increase in waste tire powder content. The shear strength of WTLS with bottom ash was 1.34 times greater than that of WTLS without bottom ash. An average increase in cohesion of 30 kPa was obtained in WTLS with the inclusion of bottom ash due to the bond strength induced from the pozzolanic reaction of the bottom ash. In this test, the maximum value of the internal friction angle was obtained with a 25% content of waste tire powder.