• Resources Recycling
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• v.4 no.4
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• pp.59-69
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• 1995

Distillation oI the dust generated during waste tue pyrolysis was perIomerl to rccover valuable metal sucll as zlnc. lead and iron. Pemcahilily and carnprcssivc tests were pursucd to ahlain the basic dala for cslraclian of zinc from the slntering propcrtp ol stccl making dusts and distilled carhon of waste tires as wcll as wastc pulp sludge mixlure hr~quet were investigated at various sinlcring lempcraturcs. Permeablllly rncieased with increastng amount of waste pulp in specil~cd istilled carhon due tn the fnrmat~ono f porusily in lhe sample TIE co~npress~vsctr ength showed the vanous values wlth different amDunl of dislilled-carhon adrlit~nilsa nd at diIIerenl sinlering tcmpcralures. X-ray diffifraction anvlyscs oI a hnquet rn~rhtre of steelmaking dusts(20Q didilled carhon and 10% waste pulp sblered ;>I SOOT) showcd thal the briquet consisted ot ZnO and Fc,O.,, hut was not found at the hriguet rintered at over 10OO'C. Crude zinc oxide sintered a1 IOOOC contained OZA Zn.

• Resources Recycling
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• v.24 no.3
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• pp.59-65
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• 2015

Recycling of vulcanized rubber products is a serious problem in the world. A quantity of generated waste tires becomes much more and more because of increasing demands on automobiles, resulted in the cause of serious secondary pollution by sulfur component that is crosslinked to incineration or landfill. In addition, crosslinked surfur is used to interfere with the binding of the raw material rubber. In this study, we analyzed the degree of devulcanization by the chemical devulcanization. Devulcanization ratio of the samples were systematically analysed by variables such as time and temperature. In addition, the effect of swelling method as a pre-treatment process was also measured. A rubber specimen was deepened in a organic 2-buthanol solutions during various times of 1 ~ 5 hrs at 100, 150, $200^{\circ}C$ respectively, then to calculate the crosslink density and the number average molecular weight by using a parallel expansion process, which showed devulcanization degree of analyzed samples quantitatively. Also, the mechanical properties were measured with the samples prepared by using a hot press.

• Elastomers and Composites
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• v.54 no.4
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• pp.330-334
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• 2019

Cryogenic crushing techniques have been employed for recycling waste rubber articles and for extracting residual organic additives present in rubber samples. Rubber particulate derived from tire tread abrasion is one of the key components of road dust. Therefore, in this work, we prepared rubber particulates using a cryogenic crusher and characterized their shapes as well as size distributions according to the type of rubber. The rubber particulates exhibited uneven surfaces with the presence of some small pieces. The order of the particle size distribution was observed to be: NR > BR > SBR. Subsequently, carbon black was added; this led to a decrease in the particle size and the shape becoming rougher. The crushed particulates of the carbon black-filled samples comprised agglomerated shapes of small pieces, which were similar in shape to that of wear debris in tire tread. It was discovered that crosslink density was one of the principal factors that led to the formation of small crushed particulates. The small particulates obtained by cryogenic crushing can be utilized as model rubber particulates for researching micro dust.

• Computers and Concrete
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• v.32 no.2
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• pp.173-184
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• 2023

In this study, mechanical, flexural post-cracking, and torsional behaviors of recycled steel fiber-reinforced concrete (RSFRC) incorporating steel fibers obtained from recycling of waste tires were investigated. Initially, three concrete mixes with different fiber contents (0, 40, and 80 kg/m³) were designed and tested in fresh and hardened states. Subsequently, the flexural post-cracking behaviors of RSFRCs were assessed by conducting three-point bending tests on notched beams. It was observed that recycled steel fibers improve the post-cracking flexural behavior in terms of energy absorption, ductility, and residual flexural strength. What's more, torsional behaviors of four RSFRC concrete beams with varying reinforcement configurations were investigated. The results indicated that RSFRCs exhibited an improved post-elastic torsional behaviors, both in terms of the torsional capacity and ductility of the beams. Additionally, numerical analyses were performed to capture the behaviors of RSFRCs in flexure and torsion. At first, inverse analyses were carried out on the results of the three-point bending tests to determine the tensile functions of RSFRC specimens. Additionally, the applicability of the obtained RSFRC tensile functions was verified by comparing the results of the conducted experiments to their numerical counterparts. Finally, it is noteworthy that, despite the scatter (i.e., non-uniqueness) in the aspect ratio of recycled steel fiber (as opposed to industrial steel fiber), their inclusion contributed to the improvement of post-cracking flexural and torsional capacities.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.203-206
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• 2006

본 논문에서는 폐타이어를 지반보강재로 재활용하는 경우 배수조건에 따른 용출특성을 알아보기 위하여 실내실험을 실시하였다 배수조건과 비배수조건으로 연속식 용출시험을 수행하여. 유출수의 pH, 탁도, TOC, Zn 농도를 분석하였다. 실험결과 배수조건인 경우 시간이 경과할수록 용출 농도가 감소하여 주변 환경에 큰 영향을 미치지 않을 것으로 판단되나, 비배수 조건인 경우 용출 농도가 증가하는 현상을 발견할 수 있었다. 배수조건은 폐타이어가 지하수위 위에 존재하는 경우이며, 비배수조건은 폐타이어가 지하수위 아래에 존재하는 경우에 해당한다. 특히, 폐타이어가 지하수위 아래에 위치하는 경우 지오텍스타일의 클로깅 등으로 인하여 배수가 원활히 되지 않을 경우에는 주변환경에 큰 영향을 미칠 것으로 예상되며 이에 대한 각별한 주의가 필요할 것이다.

• Journal of the Korea Concrete Institute
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• v.13 no.1
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• pp.54-61
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• 2001

As a part of the movement of natural resources conservation, there have been doing many recycling research works for obsolete aged tire, wasted plastic materials, etc. The purpose of this experimental study is to develop glass concrete by recycling wasted glasses as a cementitious constituent in concrete. First of all, the optimum replacement ratio of powdered waste glasses(PWG) can be determined through pilot compressive strength test on normal and high strength concrete cylinders, which have been made in various mix proportions by changing the replacement ratio of PWG. Then, further tests have been done to figure out mechanical properties of most desirable glass concrete with optimum replacement ratio of PWG, such as static modulus of elasticity, compressive and tensile strengths, flexural strength. On the other hand, the alkali-silica reactions by the mortar-bar method(KS F 2546) have been experimentally doing in various grain sizes of PWG, since the alkali in the cement has a tendency to react with the silica in the PWG. In can be confirmed from the test that glass concrete can have better workability than concrete with silica fume, and they are alike in compressive strength. It is concluded that wasted glasses can be used as pratical additives for economic and environmentally friendly concrete.

• Geomechanics and Engineering
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• v.22 no.3
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• pp.197-206
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• 2020

Reutilization of solid waste such as Tire Derived Aggregate (TDA) and mixing it with soft soil for backfill material not only reduces the required volume of backfill soil (i.e., sand-mining procedures; reinforcement), but also preserves the environment from pollution by recycling. TDA is a widely-used material that has a good track record for improving sustainable construction. This paper attempted to investigate the performance of Kaolin-TDA mixtures as a backfill material underneath a strip footing and close to a retaining wall. For this purpose, different types of TDA i.e., powdery, shredded, small-size granular (1-4 mm) and large-size granular (5-8 mm), were mixed with Kaolin at 0, 20, 40, and 60% by weight. Static surcharge load with the rate of 10 kPa per min was applied on the strip footing until the failure of footing happened. The behaviour of samples K80-G (1-4 mm) 20 and K80-G (5-8 mm) 20 were identical to that of pure Kaolin, except that the maximum footing stress had grown by roughly three times (300-310 kPa). Therefore, it can be concluded that the total flexibility of the backfill and shear strength of the strip footing have been increased by adding the TDA. The results indicate that, a significant increase in the failure vertical stress of the footing is observed at the optimum mixture content. In addition, the TDA increases the elasticity behaviour of the backfill.

• International Journal of Highway Engineering
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• v.18 no.4
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• pp.29-35
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• 2016

PURPOSES : The new waste management policy of South Korea encourages the recycling of waste materials. One material being recycled currently is tire-derived fuel (TDF) ash. TDF is composed of shredded scrap tires and is used as fuel in power plants and industrials plants, resulting in TDF ash, which has a chemical composition similar to that of the fly ash produced from coal. The purpose of this study was to evaluate the properties of an asphalt concrete mix that used TDF ash as the mineral filler. METHODS : The properties of the asphalt concrete were evaluated for different mineral filler types and contents using various measurement techniques. The fundamental physical properties of the asphalt concrete specimens such as their gradation and antistripping characteristics were measured in accordance with the KS F 3501 standard. The Marshall stability test was performed to measure the maximum load that could be supported by the specimens. The wheel tracking test was used to evaluate the rutting resistance. To investigate the moisture susceptibility of the specimens, dynamic immersion and tensile strength ratio (TSR) measurements were performed. RESULTS : The test results showed that the asphalt concrete containing TDF ash satisfied all the criteria listed in the Guide for Production and Construction of Asphalt Mixtures (Ministry of Land, Infrastructure and Transport, South Korea). In addition, TDF ash exhibited better performance than that of portland cement. The Marshall stability of the asphalt concrete with TDF ash was higher than 7500 N. Further, its dynamic stability was also higher than that listed in the guide. The results of the dynamic water immersion and the TSR showed that TDF ash shows better moisture resistance than does portland cement. CONCLUSIONS : TDF ash can be effectively recycled by being used as a mineral filler in asphalt, as it exhibits desirable physical properties. The optimal TDF ash content in asphalt concrete based on this study was determined to be 5%. In future works, the research team will compare the characteristics of asphalt concrete as function of the mineral filler types.

• Advances in materials Research
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• v.13 no.3
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• pp.221-232
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• 2024

Waste tire management and recycling have grown to be significant issues because they bring up a global environmental concern. Thus, turning recycled waste tires into useful products may help tackle the environmental issue. This research aims to study and compare the effect of recycled carbon black (rCB) and commercial carbon black (CB) at certain 15 vol. % of filler loading on the mechanical, thermal, morphology and electrical properties of epoxy/CB composites. For this project, epoxy resin, diethyltoluenediamine (DETDA), recovered carbon black (rCB) and commercial carbon black (CB) graded N330, N550, N660 and N774 were mixed and compared accordingly to the formulation determined. The CB content was dispersed in the epoxy matrix using the mechanical mixing technique. The distribution and dispersion of CB in the epoxy matrix affect the characteristics of the conductive composites. rCB content at 15 vol% was selected at fixed content for comparison purposes due to the optimum value in electrical conductivity results. The flexural strength results followed the sequence of rCB>N774>N660>N550>N330. As for electrical conductivity results, epoxy/N330 exhibited the highest conductivity value, while the others achieved a magnitude of X10^-3 due to the highest external surface area of N330. In terms of thermal stability, epoxy/N330 and epoxy/N774 were slightly more stable than epoxy/rCB.