• Resources Recycling
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• v.25 no.4
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• pp.23-31
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• 2016

It was found that there was no problem in recycling by-products (waste rock and tailings) from Yangyang iron mine themselves through matter conversion because they are not hazardous according to results of KSLT method. In case of using tailings as sub-materials of cement, it recommended the use of less than 3% tailings dosage not to exceed 0.6% of total alkali ($R_2O$) content based on standard quality of portland cement (KS L 5201). Non sintered eco-brick corresponding to class 1 quality of recycled clay brick (KS I 3013) can replace 15% of cement with tailings and 100% of general fine aggregate with waste rock from iron mine. As mentioned above, recycling the by-products (waste rock and tailings) as sub-materials of cement and non sintered eco-brick could gain both environmental and economic benefits, that is, reduction of scale and maintenance cost of tailing ponds, decrease of energy use and $CO_2$ emission.

• Resources Recycling
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• v.16 no.1 s.75
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• pp.44-53
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• 2007

The Jeonju-Il mine tailings contain large quantities of $SiO_2\;and\;Al_2O_3$ and lesser quantities of metallic components. In this study, we studied about the possibility of using mine tailings as a raw material in various industries. it was found that the sintered mine tailings had a good quality in every respect such as chromaticity, firing shrinkage and water absorption etc. Therefore if can substitute clay mineral in the ceramic industry. Also it can substitute about 2.94% of the raw materials of ordinary portland cement. We can use the coarse tailing as the fine aggregate for the ready-mixed mortar; and the fine tailing, as the filler for the bituminous paving mixture; because both products were not only suitable for Korea industrial standard in quality, but also environmentally harmless.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.4
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• pp.289-295
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• 2008

The disposal of constructive waste is emerging as a national and social issue and the recycled powder generated by the production of reproductive aggregate is all being abolished or buried Analysis on the harmful effect of recycled powder indicated that because it contained massive cytotoxicity, it could derive secondary pollution to soil and subterranean water. This study set on an idea that one way to recycle recycled powder was to use it as a compound of concrete. In order to study that prospect, recycled powder, instead of cement, was mixed and a comparative analysis was conducted on the mechanical properties and workability. From experimental results, it was judged that application of recycled powder of cement replacement ratio below 20% was available with chemical admixtures. Also application of recycled powder was available to high strength concrete.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.4
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• pp.85-94
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• 2004

Waste wood-plastic composite panels are made on different hot press molding conditions, and tested for apparent density, water absorption, expansion in thickness and flexural strength. From the test results, regardless of molding temperature and molding time, the apparent density of the composite panels is increased with an increase in the molding pressure, while their water absorption is decreased with an increase in the molding pressure. The flexural strength of the composite panels is markedly increased with increasing molding pressure, molding temperature and molding time, and tends to become nearly constant at a molding temperature of $120^{\circ}C$ and a molding time of 15min.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.777-780
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• 2008

There were some attempt to reuse water with sludge combinative water for ready mixed concrete. But recycling water consist of cement, aggregate and chemical admixture. So it caused deterioration of concrete. The object of this study was to search for recycling method of the recycling water sludge as mineral admixture. This experiment dealed with the effect of $2.5{\sim}12.5$% range of the recycling sludge which can be used for admixture binder(BFS, FA, BFS+FA) on properties of activated recycling water sludge for admixture of concrete. As a result, Although the slump levels reduced and air contents increased as sludge replacement levels increased, it didn't change highly. The compression strength of concrete slightly increased with an increasing amount of recycling water sludge replacement.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.445-448
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• 2008

It is essential that concrete component is made up with aggregate, cement and water. But today, Public concern is increasing of a variety structure and ocean environmental, resource recycle. Also, According to heat of hydration rising, Concrete is make a causative of concrete-crack. Concrete-crack cause a falling-off in quality of concrete. consequently, High-performance concrete is evaluated by concrete material properties and carbonation resistance with different admixture(fixing fly-ash 20%), granulated blast furnace slag replacement ratio (30%, 45%) different W/B (26%, 30%, 34%) and XRD(X-ray Diffraction) analysis.

• Resources Recycling
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• v.24 no.6
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• pp.31-37
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• 2015

Ground granulated blast-furnace slag (GGBFS) which is by-product of steel industry has been recycled as a cement admixture though the other steel slags are used as aggregates. In this study, the electric arc furnace slag (EAFS) was used as a cement admixture after the reduction of iron oxide in the slag at the interface of molten slag and water quenching. Consequently, the reformed EAFS (REAFS) had higher grindability than that of granulated blast furnace slag. And in mortar tests, the strength properties of specimens using REAFS were 98% of plain specimens of GGBFS upto 20% replacement ratio of GGBFS with REAFS.

• Resources Recycling
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• v.18 no.6
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• pp.46-53
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• 2009

The stone dusts produced during the manufacturing process of stone blocks are considered as one of industrial waste materials. This stone dusts are managed to either burying under the ground or stacking in the yard, but this disposal process is required an extra costs. The stone dust disposal like burying or stacking also cause environmental pollution such as ground pollution and subterranean water pollution. Thus, this study was conducted to explore the possibility of recycling stone dusts as a concrete mixing material in order to extend recycling methods. Based on the experiment results on various ratios of cement to stone dust content, the compressive strengths of concrete were recorded in the range of $20{\sim}30\;N/mm^2$. The results did not show any decrease in compressive strength due to the stone dust content. It can be concluded that the stone dusts produced by stone block manufacturing can be sufficiently recycled as one of concrete mixing materials in the aspect of compressive strength.

• Applied Chemistry for Engineering
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• v.25 no.1
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• pp.58-65
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• 2014

In this work, we constructed the sulfur-solidified materials using coal bottom ash from four thermal power stations in Korea and investigated their practical data for the production of industrial construction compounds. To manufacture the sulfur-solidified materials, we used a continuous mixer with the uniaxial screw-type. Also, coal bottom ash was used as a fine aggregate below 1.2 mm because of the operation characteristics for the continuous mixer. When the sulfur-solidified materials were produced with diverse sulfur concentrations (15, 20, 25, 30 wt%), compressive strength properties were analyzed. In addition, when the coal bottom ash was used with a high calcium oxide content, crack was found in the test product and pH of submerged liquid was above 12. These experimental results could be effectively applied to the recycling technology of coal bottom ash.

• Applied Chemistry for Engineering
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• v.23 no.2
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• pp.210-216
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• 2012

For the recycling of rapid-cooled steel slag, various specimens were prepared with the various replacement ratios of the rapid-cooled steel slag and the addition ratios of polymer binders. The physical properties of these specimens were then investigated by absorption test, compressive strength test, flexural strength test and hot water resistance test, and the pore and the micro-structure analysis was performed using scanning electron microscope. Results showed that the flexural strength increased with the increase of rapid-cooled steel slag and polymer binder, but the compressive strength showed a maximum strength at a certain proportion. By the hot water resistance test, compressive strength and flexural strength decreased remarkably and the total pore volume increased but the pore diameter decreased. SEM observation of the structure before the hot water resistance test revealed a very compact infusion of structure but the decomposition or thermal degradation appeared in polymer binders when observed after the hot water resistance test.