• Journal of the Korea Institute of Building Construction
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• v.8 no.6
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• pp.83-89
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• 2008

The stone sludge produced during the manufacturing process of stone blocks is considered as one of industrial waste materials. This stone sludge are managed to either burying under the ground or stacking in the yard, but this disposal process is required an extra costs. The stone sludge disposal like burying or stacking also cause environmental pollutions such as ground pollution and subterranean water pollution. Thus, this study was conducted to explore the possibility of recycling of stone dust sludge as a concrete mixing material in order to extend recycling methods and to solve the shortage of aggregate caused by recently increased demand in construction. Based on the experiment results on various ratios of cement to stone sludge content, the compressive strengths of concrete were recorded in the range of $20{\sim}30N/mm2$. The results did not show any decrease in compressive strength due to the stone dust content. It can be concluded that the stone sludge produced by stone block manufacturing can be sufficiently recycled as one of concrete mixing materials in the aspect of compressive strength.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.152-153
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• 2013

Based on the Fire Service Act of mandatory provision, new buildings are strictly forced to use fire protection materials. Flame resistant EPS is one of those materials. Unlike conventional EPS that can be fused to make EPS ingot and be recycled for various purposes, flame resistant EPS waste cannot be recycled due to the presence of protective coating that is applied to increase the fire protection properties of EPS. A suitable alternative that can process large amount of flame resistant EPS wastes needs to be developed, and one of the possible alternative is to use them as construction materials. In this research, experiments were designed to observe whether the flame resistant EPS wastes can be utilized as partial replacements of fine aggregates in cement mortar. The replacement ratio of waste EPS was varied, and its effect on compressive strength and absorption capacity was investigated. According to the experimental results, both compressive strength and absorption capacity met the Korean Standard specification for cement bricks and blocks, indicating that flame resistant EPS wastes can be used for construction purposes.

• Journal of the Korean GEO-environmental Society
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• v.9 no.5
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• pp.5-13
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• 2008

In this study, It was carried out to evaluate the feasibility of recycled crushed concrete as aggregate used cement mortar replace sand and to investigate engineering properties of recycled aggregate for hazardous waste solidification. The compressive strength of cement mortar replaced 5-15% (wt.) recycled aggregate was over $163kgf/cm^2$ which is the standard of first grade concrete block class C. And cement mortar was examined to evaluate the stability by leaching test. Cu, Cd, Pb, Cr, and As as the heavy metals were proved very stable but mercury (Hg) was leached high concentration because it was simply tied to the cement surface. We investigated the crystal structures of cement mortar and they had shown the peaks of $Ca(OH)_2$, ettringite, and CSH (calcium silicate hydrate). As the result, the longer curing time, the higher CSH peak that means to increase compressive strength and the cement mortar was more stable. Therefore it was shown that it may be possible to apply hazardous waste solidification using recycled aggregate, fly ash and sewage sludge ash.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.605-612
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• 2003

In this study, the performance of the cut-off wall with the specific functional adsorption layers(containing SAC), which are formed in order to block harmful materials such as heavy metal ions contained in leachate (or outflow water) from either waste landfills or exhausted mines, was Investigated by determining experimental data such as hydraulic conductivities, unconfined compression strengths, adsorption capacities. The performance was compare to those of the present cut-off wall materials such as clay, bentonite-mixed soil, and soil-cement.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.271-273
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• 2012

This paper is to investigate the effect of waste cooking oil(WCO) on carbonation resistance of high volume fly ash and blast furnace slag concrete. WCO and paint were applied for carbonation resistance materials. As expected, the application of WCO to the concrete help it reduce carbonation depth remarkably, regardless of mixture types. This may be due to the fact that WCO makes the capillary pore block by activating saponification. It is found that the degree of carbonation reduce due to WCO is much higher than the case by Paint.

• Journal of the Korea Concrete Institute
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• v.13 no.2
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• pp.87-92
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• 2001

Until now, disposal of casting foundry fly ash generally depends on reclamation. This is the great loss from a point of view saving of resources and utilizing industrial wastes. Therefore, a study on the use of fly ash as a substitute material for construction is necessary in order to utilize industrial wastes, to reduce cost of production, to improve quality in producing concrete products, and to protect environment from pollution. In this study, concrete products(hollow concrete block and concrete brick) using casting foundry fly ash as a substitute materials for cement, are produced. And experiments are conducted based on Korean Industrial Standards. Finally, the used methods of casting foundry fly ash as a substitute materials in industry are presented.

• Clean Technology
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• v.29 no.2
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• pp.102-108
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• 2023

This study applied a hydrothermal carbonization (HTC) method to carbonize sewage sludge in order to satisfy the criteria of the Waste Management Act for recycled products and to explore the possibility of recycling sludge into modification blocks. Cement was mixed with carbonized sludge generated at the optimal temperature and reaction time during HTC. After that, the compressive strengths of the modification blocks were measured by conducting both a performance and leaching test. The results of the leaching test showed that heavy metals were not detected, and the specific gravity and absorption rates were less than 1.7 and 10%, respectively, indicating that all species satisfied the criteria. The results of the compressive strength test showed that a mixing ratio of 5% and 7% with cement cured for 28 days satisfied the criteria of A, B, and C type blocks but a mixing ratio of 3% with cement did not satisfy the criteria of A type blocks after 28 days. However, after additional curing for 42 days, the mixing ratio of 3% also satisfied the A type block criteria. Therefore, the optimal mixing ratio of carbonized sludge and cement was considered to be between 3% and 5% and confirmed that the modified blocks could be utilized as aggregates.

• 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.

• Advances in concrete construction
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• v.4 no.2
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• pp.123-143
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• 2016

Use of heavy fuel fly ash (HFFA) (diesel and cracked fuel) for power generation in Saudi Arabia has generated and accumulated large quantities of HFFA as a byproduct. In this research, HFFA is studied with the emphasis on the utilization of this waste material in concrete blocks and asphalt concrete mixes. Two types of mixes, one with low and other with high cement content, were studied for concrete blocks. Different mixes having varying percentages of HFFA (0% to 25%), as cement/sand replacement or as an additive, were studied. The performance of concrete blocks is evaluated in terms of compressive strength, water absorption, durability and environmental concerns. The results showed that blocks cannot be cast if more than 15% HFFA is used; also there is a marginal reduction in the strength of all the mixes before and after being exposed to the sulfate solution for a period of ten months. HFFA is studied in asphalt concrete mixes in two ways, as an asphalt modifier (3&5%) and as a filler (50%) replacement, the results showed an improvement in stiffness and fatigue life of mixes. However, the stability and indirect tensile strength loss were found to be high as compared to the control mix due to moisture damage, indicating a need of using antistripping agents. On environmental concerns, it was found that most of the concerned elements are within acceptable limits also it is observed that lower concentration of barium is leached out with the higher HFFA concentrations, which indicates that HFFA may work as an adsorbent for this leaching element.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.4
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• pp.71-78
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• 2012

Recycled aggregates are made from construction wastes, and they have many national and social benefits by saving energy, developing substitute resources, and protecting environment. However, low-quality recycled aggregate with low density and high absorption rate cannot be used for structural concrete aggregate but is used mainly for low added value. Therefore, this study aims to identify the characteristics of the materials of recycled aggregates made after crashing and pulverizing waste concrete. For this, their major physical characteristics of cement content, absolute dry density, absorption rate, etc. were reviewed to make a mix design (draft) for the production of the secondary product and performance evaluation was done on the bending strength, absorption rate, bending strength after freezing and thawing, compressive strength, air-dried gravity, etc. of the test products produced by applying the mix design to compare the results with the quality standards of GR mark. The results of the tests showed that the substitution rate of recycled aggregate increased to 50~90 %, which is of superior quality than the performance standards of GR F 4007. Therefore, it is thought that they can be used for various construction works with certain physical characteristics applicable to the production of secondary concrete products using recycled aggregates.