• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.555-558
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• 2000

It has been increasingly proving in interest of environment pollution around the world. so, recycling of waste resources are seriously taken into consideration. Great deal of coolant for the car have been wasted for along time. due to the end of life time of them. Therefore, validities of wasted coolant as an agent for concrete are described in this paper. Mechanical properties of concrete using coolant wastes is investigated. As contents of coolant wastes increase, slump and slump flow decrease, while air content show reverse tendency. setting time shows to be accelerated with increase of waste contents. As for the effect of low curing temperature, low curing temperature increase compressive strength with increase of coolant waste. Application of coolant waste to cold weather concrete is considered to achieve favorable effects.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.327-332
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• 2003

The incinerated municipal waste can be classified into two general types of ash; fly ash and bottom ash. The fly ash is appointed as specified waste, because it contains harmful heavy metals, ie Pb , Cd, etc. more than permitted standard index. The purpose of this study is to manufacture the non-sintering artificial aggregates using municipal waste incineration fly-ash and to evaluate their applications as coarse aggregates in concrete interlocking block. The test results of water absorpsion, strengths of the concrete block using artificial aggregates showed that the artificial aggregates could be used in part of 10-20% as coarse aggregate in concrete block.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.13-14
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• 2017

In this paper, research for use possibility as silica source of waste concrete powder discharged from direct and indirect carbonation has progressed. For the research, properties on the extruding panel using waste concrete powder with high silica content is evaluated. As the results, compressive strength of specimen is increased 24% compared to control specimen when waste concrete powder replaced 50%, that is discharged from carbonation process, as silica source.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.2
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• pp.217-225
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• 2020

Concrete waste accounts for approximately 70~80% of the total waste generated during the decommissioning of nuclear power plants (NPPs). Based upon the concentration of each radionuclide, the concrete waste from the decommissioning can be used in the determination of the clearance threshold used to classify waste as radioactive. To reduce the cost of radioactive concrete waste disposal, it is important to perform decontamination before self-disposal or limited recycling. Therefore, it is necessary to estimate the internal radioactivity distribution of radioactive concrete waste to ensure effective decontamination. In this study, the performance metrics of various Compton reconstruction algorithms were compared in order to identify the best strategy to estimate the internal radioactivity distribution in concrete waste during the decommissioning of NPPs. Four reconstruction algorithms, namely, simple back-projection, filtered back-projection, maximum likelihood expectation maximization (MLEM), and energy-deconvolution MLEM (E-MLEM) were used as Compton reconstruction algorithms. Subsequently, the results obtained by using these various reconstruction algorithms were compared with one another and evaluated, using quantitative evaluation methods. The MLEM and E-MLEM reconstruction algorithms exhibited the best performance in maintaining a high image resolution and signal-to-noise ratio (SNR), respectively. The results of this study demonstrate the feasibility of using Compton images in the estimation of the internal radioactive distribution of concrete during the decommissioning of NPPs.

• Resources Recycling
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• v.10 no.1
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• pp.16-24
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• 2001

In this study, various mechanical properties of concretes employing waste concrete as aggregate were examined. These concretes were obtained by mixing seven types of aggregate for different ratios. So, the experimental variables are the kinds of aggregates (some different aggregate compositions) and W/C ratio (0.40, 0.45, 0.50). From experimental results, the reliable regression analysis equations between compressive strength and various experimental data for recycled aggregate concrete are presented. Consequently, this study was accomplished to investigate basic engineering properties of recycled aggregate concrete using waste concrete.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.20 no.1
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• pp.99-110
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• 2022

In decommissioning a nuclear power plant, numerous concrete structures need to be demolished and decontaminated. Although concrete decontamination technologies have been developed globally, concrete cutting remains problematic due to the secondary waste production and dispersion risk from concrete scabbling. To minimize workers' radiation exposure and secondary waste in dismantling and decontaminating concrete structures, the following conceptual designs were developed. A micro-blast type scabbling technology using explosive materials and a multi-dimensional contamination measurement and artificial intelligence (AI) mapping technology capable of identifying the contamination status of concrete surfaces. Trials revealed that this technology has several merits, including nuclide identification of more than 5 nuclides, radioactivity measurement capability of 0.1-10⁷ Bq·g^-1, 1.5 kg robot weight for easy handling, 10 cm robot self-running capability, 100% detonator performance, decontamination factor (DF) of 100 and 8,000 cm²·hr^-1 decontamination speed, better than that of TWI (7,500 cm²·hr^-1). Hence, the micro-blast type scabbling technology is a suitable method for concrete decontamination. As the Korean explosives industry is well developed and robot and mapping systems are supported by government research and development, this scabbling technology can efficiently aid the Korean decommissioning industry.

• Journal of the Korea Institute of Building Construction
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• v.24 no.4
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• pp.403-411
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• 2024

This study investigated the use of recycled aggregate from waste asphalt concrete in dry soil concrete mixed with red mud. The results showed that dry soil concrete utilizing waste asphalt recycled aggregate had relatively lower compressive strength compared to that using crushed aggregate. However, dry soil concrete mixed with red mud using waste asphalt recycled aggregate achieved a compressive strength of over 18.0MPa, meeting the highest performance standard for parking lot use, when the cement content was more than 250kg/m³.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.4
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• pp.314-320
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• 2014

Although the cement industry serves as the cornerstone of the construction industry by supplying one of its fundamental materials, it confronts new environmental challenges due to the problem of the $CO_2$ generated from raw materials and fuel used in the cement manufacturing process. Also, concrete structures can be decomposed and reused as construction materials. Simply in terms of the cyclic processing of $CO_2$, recycling waste concrete to manufacture recycled aggregate or recycling waste concrete powder, which is the material for cement can be considered optimally environment-friendly practices. This study contributes to the aim of manufacturing high value added materials that exploits the chemical properties of the waste concrete powder. From the research results, waste concrete powder is feasible to use to produce low carbon type recycled cement.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.7 no.2
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• pp.79-86
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• 2009

Concrete materials in nuclear facilities may become contaminated or activated by various radionuclides through different mechanism. Decommissioning and dismantling of these facilities produce considerable quantities such as concrete structure, rubble. In this paper, the characteristics distribution of the radionuclide have been investigated for the effects of the heating and grinding test for aggregate size such as gravel, sand and paste from decommissioning of the TRIGA MARK II research reactor and uranium conversion plant. The experimental results showed that most of the radionuclide could be removed from the gravel, sand aggregate and concentrated into a paste. Especially, we found that the heating temperature played an important role in separating the radionuclide from the concrete waste. Contamination of concrete is mainly concentrated in the porous paste and not in the dense aggregate such as the gravel and sand. The volume reduction rate could be achieved about 80% of activated concrete waste and about 75% of dismantled concrete waste generated from UCP.

• Magazine of the Korea Concrete Institute
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• v.10 no.4
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• pp.153-161
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• 1998

Concrete structures has been deteriorated by and freezing the thawing due to temperature gap. This study was conducted to evaluate durability of concrete which are increasingly demanded recently. Therefore the research of durability must be executed for application of waste foundry sand concrete real structures. Concrete durability properties incorporating waste foundry sand was performed with the variable of W/C ratio. Sand/Waste foundry sand ratio and Air entrainment-Non air entrainment. Cylinder specimens were made and subjected to freezing and thawing cycle at -18$^{\circ}C$ and 4$^{\circ}C$. Dynamic modulus of elasticity were evaluated as F/T cycle increase. The results show that strength of concrete is increased the W/C ratio decrease, the Sand/Waste foundry sand ratio increases when the concrete contains AE agent and decreasing W/C ratio and AE concrete makes improved resistance of freezing and thawing improved. Especially, resistance of freezing and thawing is improved by Fine aggregate/Waste foundry sand ratio which is 50%, 25%, 0% in a row. Therefore it is turn out the waste foundry sand could be applied to concrete from the experiment.