• Journal of the Korea Concrete Institute
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• v.28 no.4
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• pp.387-394
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• 2016

This study was evaluated that fundamental quality properties in the mortar level, as part of a basic study for development of fiber reinforced concrete using basalt fiber. Mortar mixtures used in the experiments used the mortar using cement only and high volume fly ash mortar using fly ash of 50%, was evaluated by comparison. As a experiments results, high volume fly ash mortar using 50% fly ash was effective for improving fiber dispersibility than mortar using cement only, accordingly, it showed that fiber aggregation phenomenon has been greatly reduced. In addition, if the fly ash used much more than 50%, the compressive strength has been shown to decrease of about 30%, fiber length and mixing ratio of basalt fiber was found to have a greater effect on flow properties than mechanical properties.

• Clean Technology
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• v.25 no.3
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• pp.179-188
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• 2019

Upon the combustion of coal particles in a coal-fired power plant, fly ash (80%) and bottom ash (20%) are unavoidably produced. Most of the ashes are, however, just dumped onto a landfill site. When the landfill site that takes the fly ash and bottom ash is saturated, further operation of the coal-fired power plant might be discontinued unless a new alternative landfill site is prepared. In this study, wet flotation separation system (floating process) was employed in order to recover unburned carbon (UC), ceramic microsphere (CM) and cleaned ash (CA), all of which serving as useful components within fly ash. The average recovered fractions of UC, CM, and CA from fly ash were 92.10, 75.75, and 69.71, respectively, while the recovered fractions of UC were higher than those of CM and CA by 16% and 22%, respectively. The combustible component (CC) within the recovered UC possessed a weight percentage as high as 52.54wt%, whereas the burning heat of UC was estimated to be $4,232kcal\;kg^{-1}$. As more carbon-containing UC is recovered from fly ash, UC is expected to be used successfully as an industrial fuel. Owing to the effects of pH, more efficient chemical separations of CM and CA, rather than UC, were obtained. The average $SiO_2$ contents within the separated CM and CA had a value of 53.55wt% and 78.66wt%, respectively, which is indicative of their plausible future application as industrial materials in many fields.

• International Journal of Highway Engineering
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• v.9 no.4
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• pp.93-104
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• 2007

This study evaluates the mechanical properties of steel fiber reinforced porous concrete for pavement according to content of slag aggregate and fly ash to elicit the presentation of data and the way to enhance its function for the practical field application of porous concrete as a material of pavement. As a result, void ratio and permeability coefficient of porous concrete for pavement increased a little as mixing rate of slag aggregates increased. Void ratio and permeability coefficient increased a lot as mixing rate of fly ash decreased. As fly ash was mixed, national regulation of permeable concrete for pavement(8% and 0.1 cm/sec) was met. Compressive strength and flexural strength decreased as mixing rate of slag aggregates increased, but they increased a lot as mixing rate of fly ash increased. Even when slag aggregates were mixed 50% with 5% fly ash mixed, national regulation of pavement concrete(18MPa and 4.5MPa) was met. In addition, compared to non-mixture, flexural strength increased about 22.8% when 0.75vol.% of steel fiber was added. Regarding sliding resistance, BPN increased as mixing rate of slag aggregates increased. But BPN decreased as fly ash was mixed. Compared to crushed stone aggregates, abrasion resistance and fleers-thaw resistance decreased as mixing rate of slag aggregates increased. When fly ash was mixed, abrasion resistance and freeze-thaw resistance improved remarkably. Compared to non-mixture, 10% mixture of fly ash improved abrasion resistance and freeze-thaw resistance about 5.6% and 14.3 respectively.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.765-768
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• 2008

The prevent methods of Alkali-Silica Reaction (ASR) are studying after the failure cases by ASR were reported in Korea. When ASR failure is causing to the step of maintenance, the available repair methods were rarely studied in the World. In this study, premixed fly ash cement was applied to prevent ASR in the concrete pavement. The ratio of fly ash and cement is 20 percent and 80 percent by weight of total cementious material. The construction performance of premixed fly ash cementious concrete pavement was studied that the application is verify to performance collected data during the constructing in the field. The freeze-thaw test was studied to verify durability of the premixed fly ash cementious material made specimen in the laboratory. The results show that construction performance and durability are well condition in this test section and freeze-thaw test.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.4
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• pp.373-379
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• 1998

Fly ash application with a rate 0, 50, 100, $150Mg\;ha^{-1}$ in clay loam paddy, which had properties of pH 5.3 and low contents of silicate, gave a positively residual effects on the growth of rice crop subsequent to malting barley. The responses of rice yields to fly ash application were in the order of bituminous coal fly ash(BCFA) 100 > 150 > 50 > anthracite fly ash(AFA) 50 > 100 > none > AFA $150Mg\;ha^{-1}$. As a result, yields responses of milled rice were ranged from $6.2(50Mg\;ha^{-1}){\sim}14.4%(100Mg\;ha^{-1})$ by BCFA and from $-0.6(150Mg\;ha^{-1}){\sim}6.6%(50Mg\;ha^{-1})$ by AFA showing maximum yields of 5.084 and $4.738Mg\;ha^{-1}$ by the former and the latter, respectively. Rice plant showed lodging indices ranging from $20(50Mg\;ha^{-1}){\sim}40%(150Mg\;ha^{-1})$ by BCFA and from $1.3(150Mg\;ha^{-1}){\sim}15%(50Mg\;ha^{-1})$ by AFA at harvesting stage. In especial, soils applicated with BCFA contained a good fertility in terms of pH, available $P_2O_5$ and $SiO_2$, and exchangeable Ca and Mg etc. so that possibly harbored 3yr-residual effects of the fly ash on crop subsequent to this rice.

• Journal of the Korea Concrete Institute
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• v.28 no.6
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• pp.647-653
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• 2016

In the paper, durability performance in FA (Fly Ash) blended concrete is evaluated considering replacement of FA with TDFA (Tire Derived Fuel Ash) from 3.0% to 12%. TDFA is a byproduct from combustion process in thermal power plant, where chopped rubber is mixed for boiling efficiency. This is the 1st study on application of TDFA to concrete as mineral admixture. For the work, concrete samples containing 0.5 of w/b (water to binder) ratio and 20% replacement ratio of FA are prepared. With replacing FA with TDFA to 12%, durability performance is evaluated regarding compressive strength, carbonation, chloride diffusion, and porosity. The results of compressive strength, carbonation, and porosity tests show reasonable improvement in durability performance to 12% replacement of TDFA. In particular, clear decreasing diffusion coefficient is observed with increasing TDFA replacement due to its packing effect. Concrete containing TDFA can be effective for durability improvement when workability is satisfied in mixing stage.

• Journal of the Korean Ceramic Society
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• v.39 no.6
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• pp.558-565
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• 2002

Coal fly ash, produced from a power plant in Korea was used for the production of glass-ceramics and the physical properties of glass-ceramics were evaluated. CaO and TiO$_2$ were added into the fly ash during the melting process to reduce the viscosity of molten glass and to induce internal crystallization of glass, respectively. Glass-ceramic was produced through a single stage heat treatment (at 950∼1050$\^{C}$ for 37∼240 min) after preparing glass (iota fly ash powder. As a result, a new tiny rod type crystals (a=7.4480, b=10.7381, c=4.3940 A, $\alpha$=94.9, $\beta$=98.6, γ=108.5°) was found in the glass-ceramics, which showed attractive mechanical properties, high hardness (7.1∼7.6 GPa) and wear resistance (by erosion test). Thus a glass-ceramic produced from thermal power plant fly ash and cell as a source for CaO exhibits a suitable treatment for the recycling and exploitation of waste materials and would be acceptable for a new application far building materials.

• Korean Journal of Environmental Agriculture
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• v.26 no.2
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• pp.141-148
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• 2007

Fly ash, a by-product of the coal-burning industry, and a potential source of ferro-alumino-silicate minerals, which contains high amount of ferric oxide and manganese oxide (electron acceptors), was selected as soil amendment for reducing methane $(CH_4)$ emission during rice cultivation. The fly ash was applied into potted soils at the rate of 0, 2, 10, and 20 Mg $ha^{-1}$ before rice transplanting. $CH_4$ flux from the potted soil with rice plants was measured along with soil Eh and floodwater pH during the cropping season. $CH_4$ emission rates measured by closed chamber method decreased gradually with the increasing levels of fly ash applied but rice yield significantly increased up to 10 Mg $ha^{-1}$ application level of the amendment. At this amendment level, total seasonal $CH_4$ emission was decreased by 20% along with 17% rice grain yield increment over the control. The decrease in total $CH_4$ emission may be attributed due to suppression of $CH_4$ production by the high content of active and free iron, and manganese oxides, which acted as oxidizing agents as well as electron acceptors. In conclusion fly ash could be considered as a feasible soil amendment for reducing total seasonal $CH_4$ emissions as well as maintaining higher grain yield potential under optimum soil nutrients balance condition.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.701-704
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• 2008

The case of failure of Alkali-silica reaction (ASR) on the cement concrete pavement was reported in Korea. In the United States America, the fly ash has less than 10 percent Cao reported that prevent expansion by ASR. Most of all fly ash in Korea have less than 10 percent CaO, therefore it is similar ASTM F fly ash in the USA. Crushed aggregates of the test section had expansion behavior by potential ASR that the ASTM C 1260 test method tested expansion 0.17 percent during 14 days. The test section of concrete pavement used crushed aggregate was constructed that fly ash have 20 percent weight of cementitious materials to prevent expansion by ASR. This study was performed flexural strength test for elapsed days and durability by freeze-thaw test. It was shown that flexural strength was increased elapsed days and good performed freeze-thaw test. This study shown that fly ash concrete pavement was good performance in the test section.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.3
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• pp.75-81
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• 2009

The industrial by-products market has increased at a geometric rate worldwide with the rapid economic growth. Among the wide variety of industrial by-products, fly ash which is generated by the combustion of coal is one of the more troublesome industrial wastes because they entail substantial disposal cost and also cause a shortage of disposal sites. In Korea alone, fly ash generation is expected to increase to 5.8 million tons by 2009, and to 6 million tons by 2010. Given the accelerated industrial development in developing countries, the amount of fly ash generation is predicted to reach enormous levels throughout the world. An increasing number of studies have currently focused on the feasibility of recycling industrial wastes i.e., fly ash in terms of environmental advantages. In this study, the optimized mix proportion of high performance shotcrete using fly ash was determined for the purpose of promoting recycling and reuse of resources.