• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.1
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• pp.58-65
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• 2021

In this study, as a method to increase the recycling of circulating fluidized bed combustion ash(CFBCA), CFBCA was utilized to produce autoclave aerated concrete product since CFBCA contains quicklime and calcium sulfate components that are required for the manufacture of autoclave aerated concrete. Successful achievement of such objective will bring cost reduction with high value addition, saving of natural resources, and the reduction of environmental load. Various mixing designs were designed to evaluate the properties of autoclave aerated concrete made of CFBCA. Based on series of experimental program, prototypes mix design for factory manufacturing was obtained. According to the experimental results, it was confirmed that gypsum can be replaced with CFBCA through the method of pre-treating the CFBCA as a slurry. It was possible to produce competitive autoclave aerated concrete products using CFBCA.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.2
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• pp.117-126
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• 2021

An experimental study was carried out to investigate the applicability of cement-based materials for green soil which is a soil for promoting plant growth. The results show that the shear strength of the green soil mixed with gypsum cement (No.3) was low, but the hardness (23.6mm) and pH value (7.4) was most suitable for the vegetation environment. In addition, the initial vegetation germination of green soil, which improved performance by adding a moisturizer, was slower than that of general green soil, and the conductivity value tended to be slightly higher. On the other hand, the slope adhesion of advanced green soil was high, and it was found that the plant growth rate and the regeneration capacity were superior after time passed.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.3
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• pp.218-225
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• 2023

In this study, we examine the feasibility of using chlorine in clinker as an early-strength cement by the effect of accelerating the cement hydration reaction of chlorine. Clinker with a chlorine content of 200-1,000 ppm was prepared using actual cement kilns, and 46 cement samples were prepared by adding gypsum and admixtures(GGBFs and limestone). We measured consistency, setting, 1-28 days compressive strength and analyzed them statistically. Test results indicated that an increase of the chlorine content resulted in shortening of initial and final setting time and the improvement of 1 day compressive strength. But the 28 days compressive strength was decreased. Specifically, when the chlorine content was increased from 230 to 965 ppm, the 1 day compressive strength increased up to 4.6 MPa, improvement effect was superior to that of increasing Blaine in the range of 3,400-3,970 cm²/g.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.57-58
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• 2015

In this research the processing method of Desulfurized Plaster is changed to cyclotomy, 0.3mm sieve analysis and 500℃ heat exposure, and by changing the mix rate of the binding agent to 0~20%, it was applied to mortar that used cyclic aggregate and blast furnace slag for testing. The test results showed that the flow decreased in the order of cyclotomy, high heat exposure, and sieve analysis according to the mix rate of FGD, and while the air volume decreased for cyclotomy, it was shown to have almost no effect on sieve analysis and high heat exposure. The setting time accelerated as the mixing rate of FGD increased, and the compression strength increased as the mixing rate of FGD increased and especially showed a high trend with cyclotomy and sieve analysis.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.55-56
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• 2015

In this research the processing method of Desulfurized Plaster is changed to cyclotomy, 0.3mm sieve analysis and 500℃ heat exposure, and by changing the mix rate of the binding agent to 0~20%, it was applied to mortar that used natural aggregate and blast furnace slag for testing. The test results showed that the sieve analysis and high heat exposure of the flow and air volume increased according to the increase of mixing rate of FGD while the cyclotomy decreased. The setting time accelerated as the mixing rate of FGD increased, and the compression strength increased to its maximum when the mixing rate of FGD was right around 10%, and especially showed a high trend with cyclotomy and sieve analysis.

• Korean Journal of Metals and Materials
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• v.46 no.7
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• pp.437-442
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• 2008

The synthesis and hydration of Calcium Sulfo Aluminate[$3CaO{\cdot}3Al_2O_3{\cdot}CaSO_4(C_4A_3{\overline{S}})$, CSA cement utilizing secondary steelmaking refining slags is studied for recycling the discarded steel plant wastes to meet the environmental requrations imposed on the steel industry. Raw materials of secondary refining slag, lime sludge, gypsum and bauxite were prepared to be sintered at $1,250^{\circ}C$. The sintered samples were hydrated for 1, 3 and 7 days to evaluate the mineralogical and physico-mechanical properties. The hydration products evaluated with the aid of SEM and XRD analyses confirmed the formation and the continuing growth of ettringite phase with the further hydration times, which plays a role in developing the early strength and the expansion properties of cements. The physico-mechanical properties of hydrated CSA products employing the recycled steelmaking refining slags determined in terms of compressive strength and linear expansion of hydrated products are found to be superior to those of the Ordinary Portland Cement(OPC) or the other commercial CSA cements.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.3
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• pp.227-234
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• 2016

In this study, asphalt paving filler, which satisfies the KS standards, were prepared from industrial by-products, such as fly ash generated from thermal power plants, cogeneration ash generated from cogeneration plants, and desulfurized gypsum generated from the flue-gas desulfurization process. The properties of the prepared mixed filler and the existing limestone filler were compared through laboratory tests for preparing asphalt mixture using each filler. In addition, asphalt pavement field tests were conducted using the limestone filler and mixed filler. The dynamic stability, Marshall stability, tensile strength ratio, saturation, porosity, and flow value of the asphalt mixtures used in the field test were evaluated, as was done in the laboratory test. The laboratory and field construction test results revealed outstanding tensile strength ratio, Marshall stability and dynamic stability when using the prepared filler than for the existing limestone filler. Through optimization of the mixing design, the possibility of developing fillers, which the characteristics of the existing limestone filler, was confirmed.

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.3
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• pp.225-232
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• 2013

The inorganic insulating material was fabricated with quartzite, ordinary portland cement(OPC), lime, anhydrous gypsum and foaming agent by hydrothermal reaction. The inorganic insulating material was fabricated by using autoclave chamber under high-temperature and high-pressure. The inorganic insulating material is a porous lightweight concrete. Because of its porous structure, properties of inorganic insulating material were light-weight and high-heat insulation property. Properties of fabricated inorganic insulating material were $0.26g/cm^3$ in specific gravity, 0.4MPa in compressive strength and 0.064W/mK in thermal conductivity. In this study, the inorganic insulating material was fabricated and analyzed at different size of quartzite/OPC, various foaming reagent and functional additives to improve the properties. Consequently, polydimethylsiloxane can improve density and thermal conductivity. Especially, polydimethylsiloxane showed excellent improvement in compressive strength.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.3
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• pp.214-221
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• 2018

In this paper, the effects of ferronickel slag powder and admixture on the strength of VR sewer pipe were analyzed. the substitution rate was tested as a variable, and the strength development was studied through the flexural strength, compressive strength and using SEM microscopic analysis. bending strength, compressive strength results and micro analysis using SEM showed the correlation in each case. the substitution rates were 20% and 30% relative to the mass of the OPC respectively, and were substituted according to a constant ratio of ferronickel slag fine powder and mixture. when the substitution ratio was 20%, the strength development was excellent. also, bending strength and compressive strength were the best when the ferronickel slag fine powder, quicklime, gypsum and calcium chloride were used as the admixture, dense microstructural patterns appeared. the possibility of progressive strength development is shown after 28 days.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.3
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• pp.90-97
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• 2009

The purpose of the study was to examine basic property at the time of applying cast ('CS' below) and high fineness fine particle cement ('FC' below) as a stimulant to 20% substitution cement mortar of ground granulated blast-furnace slag ('BS' below) to settle a problem that early strength of BS mortar is lowered. The results were as follows. First of all, as a characteristic of fresh mortar, liquidity was reduced as much as BS substitution rate was increased. When substituting CS for BS 20%, it didn't have a large effect regardless of substitution rate. When substituting FC, it was reduced as much as substitution was increased. In the event of compressive strength, it was reduced as much as BS substitution was increased in early age. In age 28, it was somewhat increased by reflection of potential hydraulicity. With regard to improvement of early compressive/bending strength of BS 20% substitution mortar, when substituting CS, in early age, they were a little increased as much as addition rate was increased. When substituting FC, in early and 28 age, they were largely increased as much as substitution rate was increased. To settle a problem that early strength of BS 20% substitution mortar was lowered, CS substitution has a little effect and FC 25% substitution was similar to plain with only OPC. Therefore, when substituting FC 25%, it is expected that its quality will be improved.