• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.3
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• pp.305-312
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• 2017

This paper presents a laboratory investigation into the effects of fillers using industrial by-product such as coal ash, IGCC slag on properties of hot-mixed asphalt concrete variation with filler content. For comparison, existing mixture with lime and dust have also been considered. Marshall and flow test has been considered for the purpose of mix design as well as evaluation of mixture. Other performance tests such as indirect tensile strength test, tensile strength ratio(moisture susceptibility), dynamic stability have also been carried out variation with filler content. It is observed that the mixes with industrial by-product exhibit conform with quality standard. Therefore, it has been recommended to utilize industrial by-product based on fly ash wherever available, not only reducing the produce cost but also partly solve the industrial by-product utilization and disposal problem.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.6
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• pp.85-91
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• 2020

The necessity for ground reinforcement of structures has been increasing in South Korea because buildings have encountered constructional problems such as inclined structures and collapses caused by earthquakes or differential settlement of the foundations. With regard to a ground reinforcement method, an increasing number of high-strength concrete piles have been used based on their advantages, including a wide range of penetration depth and a high load-bearing capacity. However, problems such as the destruction of a pile head during on-site placement work can occur when the pile has insufficient strength. For this reason, the strength of such piles should be managed more thoroughly. Thus, this study analyzed the strength properties of high-strength concrete piles using blast furnace slag (BFS) powder as a cement replacement, which was generated as an industrial byproduct. The analysis results indicated that the compression strength of the concrete piles increased when 10% to 20% of the cement was replaced with ground granulated blast-furnace slag (GGBS). In addition, the compression strength of the concrete piles was calculated to be 80.6 MPa when 20% of the cement was replaced with GGBS, which was greater by 5% than that of an ordinary Portland cement (OPC) specimen.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2000.04a
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• pp.71-71
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• 2000

Recycled fibers usually give slow drainage in the paper forming zone on papermachine, which limit the application of more refining to the fibers for improving paper strength and formation. To use recycled fibers, especially, OCC, more effectively, developing very efficient handling technique of short fibers and fines is inevitable. We tried to make hard flocs of fractionated short fibers and fines, which were the main cause of slow drainage, by adding excessive amount of retention aid on them. This technique was proved to increase drainage with no difference in strength properties, compared to the conventional technique of adding the same amount of polymers to the whole furnish in the lab test. The bonding capability of short fibers and fines in Korean OCC were very poor to be considered as ´fillers´in paper products. Various chemical treatment on the short fibers and fines of the Korean OCC did not improve their bonding and optical properties. One of the reasons of no improvement in their properties was thought to be their high amount of ashes (over 30% in the fractionated samples).

• Journal of radiological science and technology
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• v.46 no.2
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• pp.151-157
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• 2023

The purpose of this study was to develop an assist device that could correct and support patient position during biopsy on computed tomography (CT) using 3D printing technology. The development method was conducted in the order of 3D design, 3D output, intermediate evaluation for product, final assist device evaluation. The 3D design method was conducted in the order of prior research data survey, measurement, primary modeling, 3D printing, output evaluation, and supplementary modeling. The 3D output was the 3D printer (3DWOX 2X, Sindoh, Korea) with additive manufacturing technology and the polylactic acid (PLA) materials. At this time, the optimal strength was evaluated to infill degree of product as the 3D printing factors into 20%, 40%, 60%, and 80%. The intermediate evaluation and supplementation was measured noise in the region of interest (ROI) around the beam hardening artifact on the CT images. We used 128-channel MDCT (Discovery 75 HD, GE, USA) to scan with a slice thickness of 100 kVp, 150 mA, and 2.5 mm on the 3D printing product. We compared the surrounding noise of the final 3D printing product with the beginning of it. and then the strength of it according to the degree of infill was evaluated. As a result, the surrounding noise of the final and the early devices were measured at an average of 3.3 ± 0.5 HU and 7.1 ± 0.1 HU, respectively, which significantly reduced the noise of the final 3D printing product (p<0.001). We found that the percentage of infill according to the optimal strength was found to be 60%. Finally, development of assist devices for CT biopsy will be able to minimize artifacts and provide convenience to medical staff and patients.

• Journal of the Korea Concrete Institute
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• v.17 no.1 s.85
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• pp.141-147
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• 2005

The development of automobile, vessel, rail road, and machine industry leads an increase of foundry production used as their components, which cause a by-product, waste foundry sand (WFS). The amount of the WFS produced in Korea is over 700,000 tons a year, but most WFS has been buried itself and only $5{\~}6\%$ WFS is recycled as construction materials. Therefore, it is necessary for most WFS to research other ways which can be used in a higher value added product. The study on recycling it as a fine aggregate for concrete or green sand has been in progress in America and Japan since 1970s and 1980s respaectively. In this study, two types of WFS were used as a fine aggregate for concrete. Nine types of concrete aimed at the specified strength of 30 MPa were mixed with washed seashore coarse sand in which salt was removed, and WFS and then appropriate mixture proportion of concrete was determined. Moreover, basic properties such as air contents, setting time, bleeding, workability and slump loss of the fresh concrete with WFS were tested and compared with those of the concrete mixed without WFS. In addition, both compressive strength of hardened concrete at each ages and tensile strength of it at the age of 28 days were measured and discussed.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.326-332
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• 2000

It should be essentially considered as important points that design of case in electronic product which simultaneously satisfied with structural stability and molding form in respect to developmental period and economical aspect. Especially, a shape of air vents grille, which is made to emit heat happen to be in the internal of product, must satisfy durability and strength but We have no quantitative data because to be done by experience of designer. So, in this study, We will propose that structure of optimal and method of design in air vents grille, which to reduce a lot of loss of time and cost due to trial and error of design and to stabilize in the BALLISTIC Impact test as to estimate strength with external appearance of product, using linear analysis.

• Computers and Concrete
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• v.5 no.5
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• pp.449-459
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• 2008

This paper focuses on the application of two dimensional orthogonal polynomials in the regression analysis for the relationship of product parameters viz. compressive strength, bulk density and water absorption of fly ash cement bricks with other process parameters such as percentages of fly ash, sand and cement. The method has been validated by linear and non-linear two parameter regression models. The use of two dimensional orthogonal system makes the analysis computationally efficient, simple and straight forward. Corresponding co-efficient of determination and F-test are also reported to show the efficacy and reliability of the relationships. By applying the evolved relationships, the product parameters of fly ash cement bricks may be approximated for the use in construction sectors.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.54-55
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• 2013

Recently, The economic growth has increased carbon dioxide emissions. so, It is caused by social problem to environmental damage and human health due to global warming. Accordingly, The method solution is to the amount of cement and to use industrial by-product such as Blast furnace slag, Fly Ash, and Red-mud. Thus, The purpose of this study is to analyze the physical property of concrete with red-mud. So, this study carries out the basic performance test of concrete such as, air content, slump, and compressive strength. In this work test is conducted according to sequence of materials using concrete twin mixer.

• Structural Engineering and Mechanics
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• v.92 no.1
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• pp.89-97
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• 2024

Discarded cigarette butts in the environment have caused significant pollution. Therefore, providing solutions to address these environmental issues is of great importance. Concrete is known as one of the most widely used materials around the world. Hence, this study investigates the feasibility of using cigarette butts to product concrete. For this purpose, cellulose acetate fibers obtained from cigarette butt filters were added to silica fume concrete in 10 different volume ratios. Then, the mechanical properties of the concrete samples, including compressive strength, Brazilian tensile strength, and flexural tensile strength, were examined. Based on the results, adding fibers to silica fume concrete improved the mechanical properties of the concrete. Among the 10 mixing designs, adding 0.2% by volume of fibers to silica fume concrete yielded the highest compressive and tensile strengths. In other words, adding 0.2% by volume of fibers resulted in a 16% and 34% increase in compressive strength and a 70% and 38% increase in Brazilian tensile strength at 7 and 28 days, respectively, compared to the state without cellulose acetate fibers. Additionally, the flexural tensile stress capacity increased by 56%. Furthermore, the vertical deformation tolerance in beam specimens increased by 287%, and the energy absorption capacity of the concrete beam also significantly increased. Consequently, along with the significant improvement in the mechanical properties of concrete, this study proposes a new and practicalstrategy to addressthe environmental issues caused by waste cigarette butts.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.733-736
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• 2006

In the many kind of construct-material, the concrete which has the high-strength and a durability is sufficient to use with structure-material. But the color of concrete is very monotony so generally concrete isn't used the out surface. although color concrete is a method of expressing surface, the combination of pigment and cement cause many Physical problem such as efflorescence phenomenon, strength degradation and so on. In this study, It attempt to develop the black mortar using the industrial by-product and to evaluate basic physical properties compare with general color concrete to solve the color concrete problem. The result of experiment showed that Black NSC which was made by-product has more visible black color than any mortar.