• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.250-251
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• 2014

With the recent movement toward sustainable development, many efforts have been made to reduce environmental loads in various domains of industry. In particular, a great deal of research and technology development has been underway on approaches to reducing industrial waste and the emission of greenhouse gases. For this reason, a quantitative analysis of the reduction in CO₂ emission that could be achieved by replacing limestone material with cementitious waste powder was performed in this study. Through the analysis, it was found that CO₂ emissions were reduced by up to 50 percent compared with the scenario in which OPC was used, which suggests that it is possible to reduce global CO₂ emissions by approximately 5percent, or by 446.4 Tg of the 965 Tg of CO₂ emissions generated by the cement industry, in the total global CO₂ emissions of 19300Tg.

• Journal of the Korea Institute of Building Construction
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• v.4 no.2
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• pp.143-149
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• 2004

The recycle of domestic waste concrete is, however, still in an early stage, and it has been only partially being used for the road fillers. As a counter-plan of activating recycled concrete, we have confirmed the hydration possibility of the waste concrete powder from the experiment on recycling the aggregate powder since 2000. Though that study, we have known that the strength is increasing when the baking time is longer, and baking temperature maintain in $700^{\circ}C$. Also, the quality is lowered because of the fine aggregate powder which has a bad influence on flowability & compression strength by adhesion of mortar on the aggregate face. Therefore, mortar and interfacial separation of aggregate are large in proper quality for concrete recycling is expected that affect. The purpose of this study is to investigate effective aggregate separation and to determine the most suitable production method controlling the duration of baking time for recycled cement from the compressive strength, X-ray diffraction and ingredient analysis test.

• Advances in concrete construction
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• v.5 no.6
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• pp.575-586
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• 2017

The disposal of polythene waste and fly ash is causing serious threat to the environment. Aim of this study is to decrease environmental pollution by using polythene waste and fly ash in concrete. In this study, cement was partially replaced with 0%, 5%, 10%, 15% and 20% fly ash (by weight) and plastic waste was added in shredded form at 0.6% by weight of concrete. The specimens were prepared for the concrete mix of M25 grade and water to cementitious material ratio (w/c) was maintained as 0.45. Fresh concrete property like workability was examined during casting the specimens. Hardened properties were found out by carrying out the experimental work on cubes, cylinders and beams which were cast in laboratory and their behavior under test were observed at 7 & 28 days for compressive strength and at 28 days for density, flexural strength, dynamic modulus of elasticity, abrasion resistance, water permeability and impact resistance. Overall results of this study show that addition of 0.6% (by weight of the concrete) plastic waste with 10% (by weight of cement) replacement of cement by fly ash result an improvement in properties of the concrete than conventional mix.

• Computers and Concrete
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• v.23 no.3
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• pp.189-201
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• 2019

Recent advances in the concrete technology are aiding in minimizing the use of conventional materials by substituting by-products of various industries and energy sources. A large amount of stone waste i.e., dust and slurry form both are being originated during natural stone processing and causing deadily effects on the environment. The disposal problem of stone waste can be resolved effectively by using waste in construction industries. In present work, Kota stone slurry powder, as a substitution of cement was used along with accelerators namely calcium nitrate and triethanolamine as additives, to study their impact on various properties of the concrete mixtures. Kota stone slurry powder (7.5%), calcium nitrate (1%) and triethanolamine (0.05%) were used separately as well in combination in different concrete mixtures. Mechanical Strength, modulus of elasticity and electrical resistivity of concrete specimens of different mix proportions under water curing were studied experimentally. The durability properties in terms of strength and electrical resistivity against sulphate and chloride solution attack at various curing ages were also studied experimentally. Results showed that accelerators and Kota stone slurry powder separately enhanced the mechanical strength and electrical resistivity; but, their combination decreased strength at all curing ages. The durability of concrete specimens was also affected under the exposure to chemical attack too. Kota stone slurry powder found to be the most effective material among all materials. Material characterization was also done to study the microstructural properties.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.2
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• pp.115-122
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• 2018

In this paper, the feasibility of recycling concrete waste as a method to reduce final disposal amount of wastes generated through decommissioning of nuclear power plant has been analyzed based on experimental results of existing literature. When recycled concrete waste was used as recycled aggregate, it was investigated through literature that the concrete strength decreased by 30~40% depending on the mixing ratio. It was also investigated that concrete with recycled aggregate can be used as a structural material when the quality of recycled aggregate is well managed since no significant problem was found. When recycled cement produced from concrete waste was used, the strength of concrete or mortar decreased considerably as the recycled cement content increased. Therefore, it can be concluded that concrete or mortar with recycled cement can be used as a filling material for final disposal of large radioactive waste rather than for structural use. This paper is expected to be useful for reduction on disposal volume and decommissioning cost for nuclear power plants such as Kori 1.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.99-100
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• 2015

Significant amount of bottom ash has been produced in the power plant located at southeast region of Korea, but those were abandoned in the pond site without any treatment. In these days, there is a strong move to enforce environmental regulations to protect surrounding nature, a lot of pressure is given to the power plant industry to remove hazardous chemicals from their waste material before landfill or site storage. The overall objective of this research is to separate hazardous chemicals from the bottom ash, and use it safely as sustainable construction material. In this specific study, magnetic separation of bottom ash was applied, and used as a fine aggregates to make mortar specimens. According to the results, it was found that the use of bottom ash decreased 28-day compressive strength. However, using non-magnetic bottom ash provides best results in terms of thermal conductivity, showing strong possibility to be used as heat insulating material.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.04a
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• pp.12-15
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• 1993

Critical shortage of natural aggregate for production of concrete is developing in many urban area. At the same time increasing quantities of demolished concrete form deteriorated and obsolete structures are generated as a waste material in the same areas. The reuse of a waste concrete may settle the problems of environmental pollution and shortage of adquate aggregate, Therefore, this study is to reuse a waste concrete as aggregate for concrete, It is the purpose of this present study to investigate and analyze how the addition rates of superplasticizer and curing condition affect the properties of fresh and hardened recycled aggregate concrete comparing with those of ordinary concrete and crushed stone concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.51-52
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• 2023

A new shape-stable composite phase change material (PCM) have been produced via an easy and simple vacuum impregnation method. The composite PCM have been derived from almond shell biochar (ASB) as supporting material and capric acid (CA) as phase change material. Cost effective waste almond shells (AS) are renewable, eco-friendly, and rich in pores which enhance the possibility of CA impregnation. Therefore, in this study, three different ratios of CA (1:1, 1:2 and 1:3) have been incorporated in ASB to produce shape-stabilized phase change composites (ASCAs). Different techniques such as scanning electron microscopy (SEM), Fourier transform-infrared spectroscope (FT-IR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) have been applied to evaluate the characteristics of ASCAs. The attained composite PCMs have exhibited shape stability with high latent heat storage, that makes it suitable for thermal energy storage applications.

• Korean Institute of Interior Design Journal
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• v.22 no.2
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• pp.176-185
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• 2013

(Background)In modern industrial society, the design industry failed to observe the law of nature, destructing it. Regardless its intention, the design industry destructed the environment so that it can't maintain the future life because of waste and disaster. For the purpose, it is important to adopt the technology to reuse the waste resource generated by building or minimize the damage to environment for the resource that can't be recycled. (Methods)On the assumption that the material and resource can be an alternative plan for the design that can make environment be sustained, the study analyzed materials and resources out of superior office space of USA, which were selected by LEED Green Building Rating System. (Results)The analysis result revealed that all cases reused main structural part of existing building and indoor and various materials were reused or recycled. Especially, the materials without or with low amount of VOCs and formaldehyde were used. In order to reduce construction waste, the finish of existing building was exposed as it was, 50% of reused materials were used or disassemblable materials were used. When regional materials are used, there is an advantage to reduce transportation cost and recycle the materials rapidly. Lastly, the environment-friendly certified by FSC was used in all cases. (Conclusion)After all, the material is one of the space design strategies sensitive to environment so it is important to select good material. Harmless, environment-friendly materials applied to sustainable office space contribute to the creation of healthy environment. In addition, the use of recycled materials and reused materials to minimize waste is also essential factor for creating sustainable space.

• Geomechanics and Engineering
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• v.34 no.4
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• pp.449-459
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• 2023

The design and development of underground nuclear waste repositories should cover the performance evaluation of the different components such as the construction materials because the long term stability will depend on their response to the surrounding conditions. In South Korea, Gyeonju bentonite has been proposed as a candidate to be used as buffer and backfilling material, especially in the form of blocks to speed up the construction process. In this study, various cylindrical samples were prepared with different dry density and water content, and their physical and mechanical properties were analyzed and correlated with X-ray CT observations. The main objective was to characterize the samples and establish correlations for non-destructive estimation of physical and mechanical properties through the utilization of X-ray CT images. The results showed that the Uniaxial Compression Strength and the P-wave velocity have an increasing relationship with the dry density. Also, a higher water content increased the values of the measure parameters, especially for the P-wave velocity. The X-ray CT analysis indicated a clear relation between the mean CT value and the dry density, Uniaxial Compression Strength, and P-wave velocity. The effect of the higher water content was also captured by the mean CT value. Also, the relationship between the mean CT value and the dry density was used to plot CT dry densities using CT images only. Moreover, the histograms also provided information about the samples heterogeneity through the histograms' full width at half maximum values. Finally, the particle size and heterogeneity were also analyzed using the Madogram function. This function identified small particles in uniform samples and large particles in some samples as a result of poor mixing during preparation. Also, the μ_max value correlated with the heterogeneity, and higher values represented samples with larger ranges of CT values or particle densities. These image-based tools have been shown to be useful on the non-destructive characterization of bentonite samples, and the establishment of correlations to obtain physical and mechanical parameters solely from CT images.