• Title/Summary/Keyword: recycled composites

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Comparison of Mechanical and Interfacial Properties of Carbon Fiber Reinforced Recycled PET Composites with Thermoforming Temperature and Time (열 성형 온도 및 시간에 따른 탄소섬유 강화 재활용 PET 복합재료의 계면 및 기계적 물성 비교)

  • Baek, Yeong-Min;Shin, Pyeong-Su;Kim, Jong-Hyun;Park, Ha-Seung;Kwon, Dong-Jun;Park, Joung-Man
    • Composites Research
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    • v.30 no.3
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    • pp.175-180
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    • 2017
  • Currently, since carbon fiber reinforced plastics (CFRPs) are lightweight and have excellent physical properties, their demand has increased dramatically. Many works have studied the CFRPs based on recycled thermoplastics. In this study, the applicability of recycled composite was evaluated using recycled polyethylene terephthalate (PET). PET was collected from waste materials used in beverage bottles and processed to produce PET films. Optimal thermoforming temperature and time were analyzed by comparing the mechanical properties with forming temperature and time difference for producing PET films. CF mat and PET film were used to determine the suitable parameters for the optimum thermoforming of CF/PET composites. The mechanical properties of each thermoforming condition were verified by bending test. The degree of impregnation of the PET film into the CF mat was evaluated by cross-sectional photographs, whereas the interfacial properties were evaluated by interlaminar shear strength (ILSS). Ultimately, it was confirmed that the thermoforming condition for forming the CF/recycled PET composites yielding the optimal mechanical and interfacial properties was at $270^{\circ}C$ for 5 minutes.

Effect of Grading of Fine Powder obtained from Recycled Aggregates on Fundamental Properties of Slag-based Mortar (고로슬래그 미분말에 순환골재 미분말의 입도 변화에 따른 무시멘트 모르타르의 기초적 특성)

  • Huang, Jin-Guang;Park, Jae-Yong;Jung, Sang-Woon;Heo, Young-Sun;Han, Min Cheol;Han, Cheon Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2013.05a
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    • pp.37-38
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    • 2013
  • The fine powder obtained from the manufacturing process of recycled coarse aggregate contains unhydareted cement particles on their surface. It is believed that the alkalinity of the powder (11.0-12.5) is enough to active the slag-based composites. In this paper, the obtained powder was sieved and divided into two sizes, i.e., 0.08 mm and 0.3 mm, and added to the slag-based mortar. Results showed that the fine powder had an effect on the slump and the compressive strength of slag-based composites. With the different pH values of the powder, it could be seen that the distance between the two level powders. And found the peak 28 days compressive strength as the replacement ratio of the recycled aggregate powder changed. The findings from this study provide an indication that with achieved compressive strength, the fine powder can be used in a light weight concrete.

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Mechanical Properties of Polyethylene/Polypropylene/Waste Tire Rubber Powder Composites (폴리에틸렌/폴리프로필렌/폐타이어고무분말 복합체의 기계적 특성)

  • Choi, Jeong-Su;Park, Cha-Cheol
    • Elastomers and Composites
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    • v.46 no.4
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    • pp.318-323
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    • 2011
  • To recycle the waste tire rubber powder, rubber powder composite for waterproof sheet was prepared, and analyzed the effect of the kind of resin and the amount of crosslinking agent on the mechanical property of the composites. The elongation-at-break of the PE composite increased more than 3 times as EPDM was added into rubber composites. As the content of the crosslinking agent increased, the tensile strength of composite increased as well. When recycled polypropylene was used, the increase in composite's tensile strength was more than 3 times. Therefore to use the recycled PP in composite is more effective rather than PP in term mechanical properties.

Effects of Curing Conditions on Compressive Strength and Tensile Behavior of Alkali-Active Slag-Based Fiber Reinforced Composites (양생 조건이 알칼리 활성 슬래그 기반 섬유보강 복합재료의 압축강도와 인장거동에 미치는 영향)

  • Park, Se-Eon;Choi, Jeong-Il;Lee, Bang Yeon
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.9 no.3
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    • pp.260-267
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    • 2021
  • The purpose of this study was to experimentally investigate the effects of curing methods on the compressive strength and tensile behavior of alkali-activated slag-based fiber-reinforced composite with a water-to-binder ratio of 15%. Three kinds of mixtures according to the curing conditions were prepared and compressive strength and tension tests were performed. Test results showed that the compressive strength and the first cracking strength of composites decreased when high temperature curing and air curing were adopted, while tensile strain capacity of composites increased. It was also observed that crack spacing and crack width of composites decreased by applying high temperature and air curing.

Damping Characteristics of Polyurethane Composites Incorporating Recycled Rubber Particles and Aggregates (폐타이어 고무분말과 골재를 혼입한 폴리우레탄 복합재료의 감쇠 특성)

  • Park, Se Eon;Choi, Jeong-Il;Hwang, Jae-Seung;Lee, Bang Yeon
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.8 no.3
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    • pp.263-268
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    • 2020
  • The purpose of this study is to investigate the damping properties of polyurethane composites incorporating waste tire rubber powder and preplaced coarse aggregates. Four types of polyurethane-based composites were manufactured, and longitudinal impact tests were performed. And vibration signals in the time domain and frequency domain were measured and values of damping ratio for each specimen were calculated. Test results showed that the damping ratios of polyurethane composites, in which the amount of polyurethane was reduced by 10.6% and 21.2% through incorporation of rubber particles, were 8.4% and 4.6% lower than that of pure polyurethane. The damping ratio of the polyurethane composite produced in a similar manner to the prepact concrete production method was found to be 22% lower than that of pure polyurethane, however, the amount of polyurethane was reduced by 50% and the stiffness was 25.7 times higher than that of pure polyurethane.

Preliminary Study on Development of High Strength Cement Composites at 2,000kg/㎥ of Specific Weight (단위중량 2,000kg/㎥급 고강도 시멘트 복합체 개발을 위한 기초연구)

  • Jeong, Yeon-Ung;Lim, Gwi-Hwan;Kang, Yong-Hak;Jung, Sang-hwa;Kim, Joo-Hyung
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.8 no.4
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    • pp.562-570
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    • 2020
  • This study explores manufacturing technology and basic properties of high strength cement composites at 2,000kg/㎥ of specific weight. It is suggested that lightweight-high strength cement composites can be produced by substituting silica sand in ulta-high performance concrete mixture with lightweight materials such as solid bubbles and lightweight fine aggregates. The 28-day compressive strengths of cement composites with solid bubbles were from 116MPa to 141MPa at below 2.0g/㎤ of unit density while the cement composites with lightweight aggregates possessed lower compressive strength and higher unit density. The specific weight calculated from mixture proportions did not have significant difference with unit density of hardened cement composites, indicating that unit density of hardened cement composites can be estimated from the specific weight in mixture proportions.

Removal Characteristics of Heavy Metals from Aqueous Solution by Recycled Aggregate and Recycled Aggregate/Steel Slag Composites as Industrial Byproducts (산업부산물인 순환골재 및 순환골재/제강슬래그 조합을 이용한 수용액상에서의 중금속 제거 특성)

  • Shin, Woo-Seok;Kim, Young-Kee
    • Applied Chemistry for Engineering
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    • v.26 no.4
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    • pp.477-482
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    • 2015
  • This study examined the adsorption characteristics of heavy metal ions ($Cr^{6+}$, $As^{3+}$) in an aqueous solution using recycled aggregate (RA) and recycled aggregate (RA)/steel slag (SS) composites. The RA and SS are favorable for the absorbent because it contains about 91% and 86.9%, respectively, which are some of the major adsorbent ingredients (CaO, $SiO_2$, $Al_2O_3$ and $Fe_2O_3$) for heavy metal. Kinetic equilibrium of $Cr^{6+}$ and $As^{3+}$ in RA and RA/SS composites reached within 180 min and 360 min, respectively. The kinetic data presented that the slow course of adsorption follows the Pseudo first and second order models. The equilibrium data were well fitted by the Freundlich model and showed the affinity order of $As^{3+}$ > $Cr^{6+}$. The results of $As^{3+}$ also showed that the adsorption capacity slightly increased with increasing pH from 6 to 10. Meanwhile, the adsorption capacity of $Cr^{6+}$ was slightly decreased. From these results, it was concluded that the RA and RA/SS composites can be successfully used for removing the heavy metals ($Cr^{6+}$ and $As^{3+}$) from aqueous solutions.

The Characteristics and Application of Virgin FKM Rubber/Recycled FKM Rubber Blend (재생 FKM Rubber/신재 FKM Rubber 블렌드의 특성 및 응용)

  • Park, Hyun-Ho;Lee, Chang-Seop
    • Elastomers and Composites
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    • v.40 no.2
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    • pp.104-111
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    • 2005
  • Virgin fluororubber(FKM) that is one of the highly-functionalized and expensive special rubber, and recycled FKM that is crushed by high temperature shear-crushing technique from recycled FKM were blended with the various mixing ratio to rubber blends. The cure characteristics and physical properties of these blended rubber compounds were investigated with various contents of recycled FKM and physical properties fur heat and fuels were also measured. Recycled FKM which is prepared by high temperature shear-crushing technique were blended to virgin FKM with the range of $0{\sim}50$ phr. The physical properties indicated that the rubber blend of recycled FKM with 30 phr turned out to be the best compound showing good dispersibility, heat resistance and fuel resistance and inexpensive in price.

Assessment of Resistance to Application Environment of Geotextile Composites (복합형 지오텍스타일의 적용환경에 대한 저항성 평가)

  • Jeon, Han-Yong;Lyoo, Won-Seok;Ghim, Han-Do;Chung, Chin-Gyo;Cho, Bong-Gyun
    • Journal of the Korean Geosynthetics Society
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    • v.2 no.3
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    • pp.25-38
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    • 2003
  • Geotextile composites to improve the resistance to the application environment were manufactured of recycled polyester geotextile with carbon black as ultraviolet stabilizer and polypropylene geotextile by needle-punching method. Mechanical properties, ultraviolet resistance and chemical stability were evaluated. Retention ratio of tensile properties of polypropylene geotextiles were decreased about 50% with the exposed condition by ultraviolet but those of geotextile composites showed the slightly decrease. Geotextile composites which have larger weights of recycled polyester geotextile were more stable against ultraviolet. For chemical stability, the changes of tensile strength values of geotextile composites were in the range of -20~+10% at the various chemical conditions.

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Non-destructive Analysis of Nano-Cementitious Composites Using Ultrasonic and Electrical Resistance (초음파 및 전기저항을 활용한 나노-시멘트 복합체의 비파괴 분석)

  • Shin, Yangsub;Lee, Heeyoung;Cho, Sanghyeon;Park, Sohyeon;Chung, Wonseok
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.9 no.3
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    • pp.322-329
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    • 2021
  • Nano-cementitious composites may have defects due to poor dispersion of nanomaterials and fabrication process. These defects can cause critical problems for nano-cementitious composites, but studies related to non-destructive analysis of defects sizes inside nano-cementitious composites are insufficient. This study aims to perform non-destructive analysis of nano-cementitious composites by utilizing ultrasonic and electrical resistance. Various sizes of defects were implemented inside the specimens and the specimens were subjected to ultrasonic non-destructive analysis and electrical resistance non-destructive analysis depending on the size of defects and curing days. As a result of the experiment, ultrasonic pulse velocity decreased by up to 11% as the defects size increased, and the electrical resistance increased by up to 14% depending on the defects size. For this reason, this study concluded that non-destructive analysis using ultrasonic and electrical resistance can predict defects inside nano-cementitious composites.