The study is aimed to utilize the silica fume coated plastic waste in the concrete in place of uncoated plastic waste. The main aim of the study is to evaluate the effect on fresh and mechanical ...properties of concrete after coating the plastic waste with mineral admixture i.e silica fume. The study of utilization of different kinds of plastics forms in concrete has been carried out earlier as well. The major concern is the bonding between concrete mix and the plastic by which the strength could not be attained as desired as per the grade. The present investigation is an endeavor to enhance the bonding characteristics of waste PET fibers with concrete mix by coating them with mineral admixture such as silica fumes by utilizing epoxy resins as an adhesive. The examination was done by utilizing waste PET fibers in aspect ratio AR 25 (50 mm נ2 mm), AR 50 (100 mm נ2 mm) and AR 75(150 mm/2 mm) and consolidate them as bond weight in separate interims of 3%, 6%, 9% and 12%. The modern and mechanical qualities of concrete mix investigated with incorporation of silica fume coated waste PET fibers and ordinary waste PET fibers were contemplated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Antimony (Sb), a regulated contaminant, is added as a catalyst in the process of polyethylene terephthalate (PET) synthesis. Previously, Sb release from PET bottles and films was studied. However, Sb ...release from PET fibers (the most common form of PET) is limited. Therefore, a network model of material flow for PET fibers in China is developed, and the anthropogenic Sb flow and release entering into the hydrosphere, pedosphere, and atmosphere are studied based on microexperiments and macromodels. To compensate for the uncertainty caused by material flow analysis, Sb pollution in the surrounding areas (the drinking water of nearby residents and sediments of nearby river area) is further explored by combining field investigations and sample analysis. The results are as follows: 1) the manufacture stage of PET fibers is the main source of Sb release (2926 t), followed by the dyeing (2223 t) and weaving (908 t) stages; 2) Sb release (1108 t) from waste PET fibers subjected to landfill disposal is the highest. Sb release (872 t) from discarded fiber waste is second highest. Sb release from PET fibers subjected to mechanical recycling, incineration, and chemical recycling is 784, 284, and 25 t, respectively; and 3) an obvious source-sink relationship is found between anthropogenic Sb in the rivers and sediments and the intensity of the industries. This study suggests that Sb from PET fibers should be properly managed to prevent widespread dispersion in the hydrosphere, pedosphere, and atmosphere.
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•A network model of material flow for PET fibers is developed.•Sb pollution near PET fibers industries is explored based on the Igeo index.•The manufacture of the PET fibers stage is the main source of Sb release.•Strong mobility of Sb in the rivers will most likely threaten drinking water.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Green concrete composite produced from Polyethylene terephthalate (PET) fibers may be considered an important issue in sustainable construction. Therefore, the behavior of self-compacting concrete ...(SCC) slabs containing PET fibers under impact loads was investigated. PET fibers from waste plastic were added to SCC with an aspect ratio of 28. One reference concrete mix, from which all other mixes were developed, was used to produce eight SCC mixers containing different volumetric ratios of plastic fibers percentages (0.25%, 0.5%, 0.75%, 1%, 1.25%, 1.5%, 1.75%, and 2%). Experiments showed that the inclusion of PET fibers in SCC results in an increase in compressive and flexural strengths. The behavior of SCC slabs under impact loading was studied. A significant improvement was found in the resistance to impact load and energy absorption capacity of slabs containing PET fibers. The increment in the time of max deflection for the concrete mixes containing PET fibers increased significantly, thereby indicating the enhanced capacity of SCC to absorb further energy under low velocity impact. This improvement in the behavior of SCC under impact by the inclusion of PET fibers may lead to further applications of this type of concrete in sustainable structures.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Strain-Hardening Cementitious Composite (SHCC) is a type of advanced construction material that can enhance the resiliency and durability of structures. However, the high cost of the constituents ...limits the wide application of SHCCs. To reduce the material cost and improve the sustainability, this study explores the potential of replacing commonly-used polyvinyl alcohol (PVA) fibers by recycled polyethylene terephthalate (PET) fibers. The potential of fiber hybridization was first evaluated using micromechanical modeling, and the ultimate tensile strain of hybrid-fiber SHCCs was estimated using a semi-empirical method. Then the tensile performance of SHCCs after standard curing and accelerated aging was experimentally evaluated, and the crack pattern development with increasing tensile strain was recorded. Satisfactory mechanical performance can be achieved even when 50% of PVA fibers are replaced by recycled PET fibers with surface treatment. In addition, using recycled PET fibers in SHCCs can significantly reduce the material cost and environmental impact.
•SHCCs with hybrid PVA/PET fibers are theoretically and experimentally studied.•A semi-empirical way to predict strain capacity of hybrid-fiber SHCCs is proposed.•The impacts of PET fiber surface treatment and curing time are explored.•SHCCs achieve satisfactory performance even 50% PVA fibers are replaced by PET fibers.•Using PET fibers in SHCCs effectively reduces material cost and environmental impact.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
RESUMEN La gestión inadecuada de los residuos de botellas de plástico está teniendo un impacto negativo en el ambiente. El reciclaje de estos residuos para su inclusión en la matriz del hormigón es ...una alternativa viable para su disposición final. El objetivo de este estudio fue evaluar el comportamiento mecánico del hormigón convencional con la adición de fibras de politereftalato de etileno (PET), diseñado según los procedimientos establecidos por el Instituto Americano del Concreto para una resistencia de 20 MPa. Las propiedades analizadas del hormigón incluyeron la consistencia, densidad, resistencia a compresión y flexión. Se elaboraron 60 especímenes cilíndricos y 60 prismáticos con adiciones de fibras PET del 0 %, 2 %, 4 %, 6 % y 8 % respecto al peso del cemento para ensayarlos a roturas a los 7, 14 y 28 días de curado. Los resultados indican que se alcanzan resistencias a compresión y flexión máximas de 22.79 MPa y 3.19 MPa, a los 28 días con la adición del 2 % y el 6 % de fibras PET, respectivamente. Por lo tanto, se recomienda su aplicación hasta una proporción del 4 %, donde la dosificación correspondiente es de 15.78 kilogramos de fibras PET por metro cúbico de hormigón con una consistencia trabajable.
Rubber aggregate recycled from waste tires are added to self-compacting concrete to improve some of its properties, such as durability, toughness, and concrete resistance to impact and vibrations. In ...this study, modified hybrid rubberized self-compacting concrete (SCC) was produced by utilization of recycled tire rubber aggregate, plastic waste (PET), and steel fibers. Rubber was used as a partial substitute for sand, with only 10%, while the fibers were utilized in two different proportions of 0.25% and 0.35% (volume). Several tests were achieved to evaluate the rheological properties of the modified hybrid fiber rubberized SCC such as slump flow, T500, V-funnel, L-box, and segregation resistance. In addition, the hardened properties such as density, compressive, tensile strengths, and modulus of elasticity were evaluated. Microstructural evaluation of rubberized mixes was conducted. The results showed that the addition of rubber aggregate at 10% content reduces the rheological properties of SCC. The T500 mm was influenced significantly up to 15% increase. Moreover, compressive strength decreased by about 14% at same amount of rubber aggregate, while the addition of hybrid fibers improves the mechanical properties despite the negative effect on the rheological properties of rubberized SCC. The tensile strengths increased significantly by the inclusion of 0.35% hybrid fibers. The positive action of the two types of fibers led to this increase. The combination of rubber aggregate and the hybrid fibers in SCC could affect its mechanical properties positively by balancing the weakness in strength due to the lack in of bonding between rubber aggregate and cement paste and to avoid the severe deterioration in tensile strength, improve the ductility, and enhance the energy absorption capacity, especially for members subjected to earthquake effects.
•Crumb tire rubber aggregate, plastic waste (PET), and hooked ended steel fibers was utilized in this study.•Several tests were achieved to evaluate the rheological properties..•The hybrid fibers improve the internal cohesion and interaction of rubberized SCC.•The low content of rubber aggregate (10%) maintained an acceptable reduction in strengths.•There was a balance between the reduction in fresh properties and the desired strength.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In recent years, plastic wastes represents one of the main threats to the environment. However, the use plastic fibers in concrete could be a sustainable solution to the problem of plastic waste ...accumulation. Moreover, the use of fibers in the production of concrete is one attempt to remedy this brittleness and to enhance other properties such as toughness and ductility. In this study, polyethylene terephthalate (PET) fibers produced from waste plastic bottles was used in reinforced concrete RC beams. PET fibers were included in concrete at two percentages (0.5% and 1% by volume). The influence of layered distributions of PET fibers in concrete on the flexural behavior of beams was also evaluated. For each mix, three layered PET fibers RC beams were prepared. Comparison with beam containing the same PET fiber percentage (full section) was presented as well. The flexural test parameters included the determination of first cracking, the yield, and the ultimate load, in addition to the deflections related to these loads. Furthermore, failure modes, toughness, and ductility were also evaluated. The use of PET fiber concrete with a layered distribution enhanced the ultimate load considerably. Moreover, the load–deflection relationships illustrated a tendency of layered PET fibers concrete beams to exhibit further deflections before failure. The toughness capacity approximately doubled for beams reinforced with 1% PET fibers concrete in the bottom quarter, bottom half, and top half sections of layered RC beams. This impressive enhancement of the flexural toughness and ductility using the layered distribution is a promising finding that could promote this type of sustainable concrete in various structural applications.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•SHCC reinforced by PET fibers showed poorer tensile performance than SHCC with PVA fibers.•In the modified Charpy impact test, PET-SHCC dissipated a similar amount of energy as PVA-SHCC.•Both ...modeling and tests show that a stronger interfacial bond doesn’t always lead to a higher impact energy absorption.
Strain Hardening Cementitious Composites (SHCC) are fiber reinforced composites exhibiting strain hardening and multiple cracking behaviors. The Polyvinyl Alcohol (PVA) fibers used in SHCC are expensive for normal civil engineering applications, so one kind of Polyethylene terephthalate (PET) fibers recycled from waste plastics are used in this study as a substitute of PVA fibers. Uniaxial tensile test was carried out on SHCC samples made with PVA or PET fibers where the PET-SHCC was found to behave poorer than the PVA-SHCC due to the weaker bond between PET fibers and matrix. Nevertheless, in the modified Charpy impact test which was designed to evaluate the impact energy absorption ability of SHCC, the PET-SHCC dissipated a great amount of energy comparable to that by PVA-SHCC, indicating that PET fibers can provide excellent impact resistance to cementitious composites. To reveal the mechanism of impact energy absorption, a physical model was developed to simulate the impact test, which can well support the experimental observations. Based on above findings, a hybrid mix of 1 vol% PVA fibers and 1 vol% PET fibers is recommended for practical applications to provide adequate tensile performance and excellent impact resistance with eco-friendly ingredients at low cost.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
A tremendous amount of polyester textile waste is discarded every year, which has caused a serious problem for the environment. In this study, the feasibility of circular recycling of polyester ...textile waste is investigated through a glycolysis process in the presence of environmentally friendly Mg–Al double oxides pellets as catalyst. Even though the catalytic performance of Mg–Al double oxides pellets is slightly lower than their granules at 240 °C, pellets were used as they benefit from a good recyclability. The pellet catalysts could be cycled three times without losing structural integrity or catalytic activity in the glycolysis of (poly(ethylene terephthalate)(PET)). However, to restore the catalytic activity after three cycles, the catalyst was regenerated through a heat treatment after the glycolysis reaction. After that the catalyst showed a comparable catalytic activity as that of virgin catalyst. In the glycolysis process, the monomer bis(hydroxyethyl) terephthalate (BHET) is generated and recovered. The molar yield of BHET was in the reaction over 80 mol%. From the recovered BHET, regenerated PET (r-PET) with an intrinsic viscosity (IV) of 0.67 was synthesized. The r-PET showed a very good spinnability in the melt spinning test. The quality of the obtained r-PET fibers was comparable to virgin PET fibers.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this study, we compared the properties of recycled poly(ethylene terephthalate) (PET) fibers and virgin PET fibers. All these experiments present the differences or similarities between them on ...surface morphology, mechanical properties, and internal fiber structure. The results show that the surface morphology of both PET fibers is similar. According to the tests on mechanical properties, it can be observed that recycled PET fibers have a higher tensile strength and greater elongation at break. The recycled fiber has a higher degree of crystallinity while with the smaller average crystallite size based on the X-ray diffraction data. In polarized attenuated total reflectance infrared technique, the virgin fibers have a better performance than the recycled ones in orientation. Fourier Transform Infrared spectrum analysis indicates that both kinds of fibers have the similar representative groups.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
