Fiber Reinforced Polymer Waste Research Articles

Properties of concrete with glass fibre reinforced polymer waste as partial replacement of fine aggregate

The proper disposal of fibre waste products is a significant issue for the GFRP industries; as a result, the reuse and recycling of these waste products require sustainable solutions. Given that FRP materials, especially those created with thermosetting resins, cannot be reprocessed, so the majority of thermosetting FRP waste will be dumped in landfills. Innovative approaches are thus required to manage waste. This study investigates the performance of the FRP waste, known as Glass Fibre Reinforced Polymer (GFRP), that is ground to 0.15mm to 2.36mm in size and used to replace sand at 5%, 10%, 15%, 20%, and 25% by weight of the concrete composite. The experimental work starts with the grinding and sieving process, followed by preparing grade 45 concrete. Then the workability of concrete with GFRP was determined, followed by the compression, and split tensile strengths. The findings showed that adding up to 5% of GFRP waste as a partial replacement for fine aggregate improved the workability and compressive strength of the concrete mix. but decreases when more GFRP waste is added. While the split tensile strength shows increments in line with the increasing amount of GFRP waste replacement. It can be concluded that GFRP waste replacement has the potential to be used in the construction industry, however, the long-term performance must be determined first.

Flexural performance of layered macro fiber reinforced concrete beams

Fiber-reinforced polymer (FRP) composites have been increasingly used in various sectors, which inevitably results in an increasing amount of FRP waste to be dealt with. A recent study conducted by the authors’ group explored a novel mechanical recycling method to process glass fiber-reinforced polymer (GFRP) waste into small slender elements (referred to as “macro fibers”) for reinforcing concrete, leading to so called “macro fibre reinforced concrete” (i.e., MFRC). The macro fibres recycled from waste FRP composites shows to effectively enhance the tensile performance of the resulting concrete (e.g., tensile strength, tensile toughness), while have a negligible effect on the compressive properties of MFRC. The concept of the layered beams has been therefore adopted with the bottom layer fabricated with MFRC and the top layer with plain concrete (PC) to improve the utilization and added values of the macro fibers from the structural level. A series of tests were conducted to justify the proposed technique. Test results indicate that an increase of 4.6%, 27.6%, and 44.3% in splitting tensile strength was observed for concrete with a macro fiber content of 1%, 1.5%, and 2%, respectively. Some of other mechanical properties of the resulting concrete (e.g., the compressive toughness, flexural strength and flexural toughness) were apparently enhanced as well by the incorporation of macro fibers. In addition, the flexural performance of concrete beams shows to be superior if the macro fibers mainly concentrated in the bottom layer (i.e., a layered beam), demonstrating a higher utilization and added values of macro fibers achieved by the application of layered beams.

Advances in the circularity of end-of-life fibre-reinforced polymers by microwave intensification

The growing use of fibre-reinforced polymer (FRP) composites and the increasing global generation of FRP waste implies an urgent need to develop a circular economy strategy to promote the recovery of fibres and the valorisation of resins. This review paper analyses the current scenario of FRP recycling technologies and evaluates the potentials of microwave-assisted heating as a technology to provide an intensification in terms of energy-efficiency, selective heating and processing speed, as well as an electrified thermal treatment for FRP recycling. The paper presents an overview of the estimated FRP production and waste generation per sector in the coming decennia and the current and envisioned international legislation related to the management of end-of-life FRP. The paper also discusses the strong and weak points of the existing FRP recycling technologies, their readiness level and overall environmental impact in terms of equivalent CO2 emissions. Furthermore, the emerging microwave-assisted FRP recycling technology is evaluated, showcasing the potentials and obstacles for its implementation and the potential end-use and characteristics of the recycled components. A literature survey on the existing prototypes, MW-assisted waste-to-value processes and reported energy demand is conducted. Finally, the required resources and framework for the consolidation of the MW-assisted FRP recycling as an alternative and economically viable technology are assessed.

A Thermodynamic Perspective on Wind Turbine Glass Fiber Reinforced Polymer Waste as a Supplementary Cementitious Material

A Thermodynamic Perspective on Wind Turbine Glass Fiber Reinforced Polymer Waste as a Supplementary Cementitious Material

Concrete reinforced with macro fibres recycled from waste GFRP

Fibre reinforced polymer (FRP) composites are widely used in many industries due to their excellent mechanical and durability properties. This means that an increasing amount of FRP waste, arising from production, processing and decommissioning, needs to be processed. Common FRP composites are normally thermoset and non-biodegradable, posing a significant environmental threat if they are not disposed of properly at their end of life. While recycling of FRP is environmentally desirable, almost all existing recycling methods, which are based on either thermal, chemical or mechanical processes, are economically unviable if governmental subsides are not available. The recycling of glass FRP (GFRP) waste, which accounts for over 95% of all types of FRP waste by weight, is even more economically challenging than the recycling of carbon FRP (CFRP) waste due to the lesser economic value of the former. This paper explores a novel mechanical method for recycling GFRP waste by processing it into macro fibres for reinforcing concrete, with the resulting material referred to as macro fibre reinforced concrete (MFRC). The mechanical properties of MFRC were investigated. The test results showed that the addition of macro fibres had two major effects on the concrete: (1) the workability of concrete depends strongly on the macro fibre volume ratio, with the slump value reducing from 176 mm to 83 mm as the macro fibre volume ratio increased from 0% to 1.5%; (2) the flexural strength and toughness of the concrete be greatly enhanced by the addition of macro fibres, e.g., by 1.3 and 230 times when the macro fire value ratio was 1.5%. The proposed recycling method for waste GFRP is therefore believed to be both technically feasible and economically attractive.

Physical, mechanical and thermal behavior of concrete block stabilized with glass fiber reinforced polymer waste

The Glass Fiber Reinforced Polymer (GFRP) waste despite having excellent physical and mechanical properties is still largely unexplored besides presenting large volume of waste with very low degradability. The use of concrete block presents high resistance to compression, low price high masonry coating ratio by material weight, however high thermal conductivity. Therefore, the study aimed to produce and investigate the effect of adding GRFP residues to concrete blocks due to physical, mechanical and thermal properties. The compositions were made by replacing the fine gravel between 0 to 10% in mass by the GFRP residue. They were evaluated from physical, mechanical and thermal tests. The results showed that the use of GFRP residue did not interfere in water absorption and compressive strength, despite the significant increase in mechanical energy absorption of the material. Thermal conductivity reduced by 46% and the concrete blocks were 7% lighter. In addition to providing a destination for a considerable quantity of the waste, the commercial value of the final product is higher due to using a residue with low degradability and high energy power due to burning during recycling.

Shear behavior of reinforced concrete beams with GFRP needles

Fiber-reinforced polymer (FRP) waste is becoming an environmental concern due to the widespread use and non-biodegradable nature of FRP composites. Cutting FRP waste into short-length randomly distributed reinforcing bars (referred to as “needles” hereafter) as a substitute for part of the coarse aggregate in concrete has been suggested as a possible solution to FRP waste recycling. This paper presents to the authors’ best knowledge the first reported experimental investigation into the effect of GFRP needles as coarse aggregate partial replacement in concrete on the shear behavior of large-scale reinforced concrete (RC) beams. A total of 10 RC beams without steel stirrups in the critical half were tested under four-point bending. The volume replacement ratio of coarse aggregate and the surface type of GFRP needles were chosen as the test parameters. All test beams failed in shear in a brittle manner with their ductility being slightly enhanced by the partial replacement of coarse aggregate using GFRP needles. An enhancement of 8–10% in the load-carrying capacity was observed in beams with helically wrapped needles, while beams with smooth needles showed a slight reduction in the load-carrying capacity. The presence of GFRP needles increased the amount of total energy absorbed by the RC beams by about 33–40%.

Investigation of surface modification and volume content of glass and carbon fibres from fibre reinforced polymer waste for reinforcing concrete

The proportion of composites, mainly glass and carbon fibre-reinforced polymers (FRP) in the material cycle have been increasing for years in many sectors. Landfilling of FRP waste is forbidden and recycling is still an unsolved issue. Aim of this paper is the investigation of a feasible reuse of FRP as reinforcement in concrete as shredded material or as thermally recovered plain carbon fibres.A huge amount of glass fibre polymer waste is generated in the wind energy sector and shows low alkaline resistance which is not directly applicable as a reinforcement in alkaline concrete without any surface protection. Therefore, different surface treatments were conducted: on the one hand the aim is to protect FRP fragments in concrete and on the other hand to improve the adhesion. The results of pull-out tests show that a sanded surface of glass fibre polymers increases the averaged maximum shear strength by 16 %.Investigation of the influence of different volume contents (0.25, 0.5, 1 and 2 Vol.-%) of recycled, pyrolized carbon fibres with a varying fibre length show a maximum flexural strength at 1 Vol.-% in bending tests on fibre reinforced concrete. Compared to plain concrete an increase of +111 % can be observed.

Physical, mechanical and thermal behavior of adobe stabilized with glass fiber reinforced polymer waste

The polymer industry develops materials with excellent physical and mechanical properties but also with a large volume of waste with very low degradability. Therefore, the objective of this paper was to use glass fiber reinforced polymer (GFRP) waste in adobe production. Compositions varying from 0 to 10% mass residues were produced and evaluated in physical, mechanical and thermal tests. The addition of 10% GFRP waste showed the best results when compared to adobe without additives, demonstrated as follows: shrinkage reduction of 239%; bulk density reduction of 6%; thermal conductivity reduction of 21%; mass loss reduction when submerged in water; and compressive strength increase of 45%. Therefore, the use of GFRP residue is indicated in the manufacture of adobe to improve its physical, mechanical and thermal conductivity properties. In addition to providing a destination for a considerable quantity of the waste, the commercial value of the final product is higher due to using a residue with low degradability and high energy power due to burning during recycling.

Assessment of glass fibre reinforced polymer waste reuse as filler in mortars

Fibre reinforced polymer composite materials (FRP) have been extensively used worldwide as substitutes of other traditional materials due to their lightness, high mechanical performance, high chemical resistance and the possibility of having any shape required. The waste management of these materials is critical because most of the wastes produced are sent to landfills.This research intends to evaluate the influence of Glass Fibre Reinforced Polymer (GFRP) waste as a filler in cement-based mortars. The technical performance of the renders with GFRP was analysed in order to find a viable solution to recycle this waste. Two sets of mortars were analysed: mortars with a similar workability and mortars with the same water/binder ratio both with percentages of GFRP waste incorporation of 10%, 15%, 20% and 50%. The water behaviour was analysed through the water absorption by capillarity test and drying test. The mechanical behaviour was analysed through the dynamic modulus of elasticity, velocity of ultrasound waves, flexural strength and compressive strength.The incorporation of GFRP by-products in mortars is a viable solution for the reutilization of this waste. The GFRP waste improved the workability of the mortars and reduced their bulk density. The modified mortar with best technical performance was the mortar with 50% of GFRP by-product as substitute of natural aggregate. The initial water absorption of these mortar was reduced by over 80% (measured by the coefficient of capillarity) and the mechanical strength was significantly improved: at 365 days, there was an increase in flexural strength of 155% and in compressive strength of 166%.

Comparative environmental and human health evaluations of thermolysis and solvolysis recycling technologies of carbon fiber reinforced polymer waste

This quantitative research aims to compare environmental and human health impacts associated with two recycling technologies of CFRP waste. The ‘baseline’ recycling technology is the conventional thermolysis process via pyrolysis and the ‘alternative’ recycling technology is an emerging chemical treatment via solvolysis using supercritical water (SCW) to digest the thermoset matrix. Two Gate-to-Gate recycling models are developed using GaBi LCA platform. The selected functional unit (FU) is 1 kg CFRP waste and the geographical boundary of this comparative LCIA is defined to be within the U.S. The results of this comparative assessment brought to light new insights about the environmental and human health impacts of CFRP waste recycling via solvolysis using SCW and, therefore, helped close a gap in the current state of knowledge about sustainability of SCW-based solvolysis as compared to pyrolysis. Two research questions are posed to identify whether solvolysis recycling offers more environmental and human health gains relative to the conventional pyrolysis recycling. These research questions lay the basis for formulating two null hypotheses (H0,1 and H0,2) and their associated research hypotheses (H1,1 and H1,2). LCIA results interpretation included ‘base case’ scenarios, ‘sensitivity studies,’ and ‘scenarios analysis.’ The results revealed that: (a) recycling via solvolysis using SCW exhibits no gains in environmental and human health impacts relative to those impacts associated with recycling via pyrolysis and (b) use of natural gas in lieu of electricity for pyrolyzer’s heating reduces the environmental and human health impacts by 37% (lowest) and up to 95.7% (highest). It is recommended that on-going experimental efforts that focus only on identifying the best solvent for solvolysis-based recycling should also consider quantification of the energy intensity as well as environmental and human health impacts of the proposed solvents.

Reuse FRP waste as filler replacement for sisal fiber reinforced sheet molding compound

Sisal fiber (SF) reinforced sheet molding compound (SMC) was prepared by compression molding technology. The fiber reinforced polymer (FRP) waste was added to replace calcium carbonate, which could be regarded as an effective solution of FRP waste. FRP loading of 20, 25, 30, and 35 wt% were incorporated to matrix and the mechanical, thermal stability, and water absorption of the SF‐SMC were investigated. The results of Fourier transform infrared spectroscopy confirmed that the silane coupling agent was successfully grafted on the surface of FRP waste. Scanning electron microscopy (SEM) was used to observe the surface micro‐structure of SF and FRP waste. Thermogravimetric analysis was used to investigate the thermal stability of the FRP waste and SF‐SMC. Water absorption and water contact of the SF‐SMC were also tested. SF‐SMC fabricated with 30 wt% FRP waste powder possessed the best mechanical, thermal, and water absorption property due to the good interfacial adhesion between fibers and matrix. POLYM. COMPOS., 39:1896–1904, 2018. © 2016 Society of Plastics Engineers

Use of recycled FRP reinforcing bar in concrete as coarse aggregate and its impact on the mechanical properties of concrete

The production of fiber reinforced polymer (FRP) composite materials is a major source of non-degradable waste. The use of FRP bars for reinforcing concrete is increasing in construction. This study investigates the impact of replacing coarse natural aggregate (NA) in concrete with cut FRP bar waste (FRP-RA) on the compressive and tensile strength of both high strength and normal strength concretes. Concrete cylinders without any FRP-RA, with 40% of NA (the large-grade particles) replaced with FRP-RA, and with 100% of NA replaced with equivalently graded FRP-RA were tested. The results show that the effect of the FRP-RA on the mentioned mechanical properties depends on the concrete strength, replacement ratio and the gradation-size of the NAs replaced. High-strength concrete performed better than low strength concrete and replacement of larger sized NA with FRP-RA resulted in better performance compared to full replacement. The test results show that existing empirical models can sometimes overestimate the tensile strength of lower-strength FRP-RA concretes. The findings show that although the use of FRP waste in concrete reduces the strength, concrete with structural grade mechanical properties can be produced with FRP-RA. The potential durability issues of FRP-RA concrete are discussed and future studies on this topic is proposed.

A Critical Review of Research on Reuse of Mechanically Recycled FRP Production and End-of-Life Waste for Construction

For the last three decades, fiber reinforced polymer (FRP) composite materials have been widely used in major engineering industries. Managing FRP waste is becoming an important issue due to the growth in the production of FRP composite materials. In this article, the issue of FRP waste management is discussed and the commonly used methods for the handling of FRP waste are reviewed. One potentially viable use of FRP waste is in the partial replacement of fillers or aggregates in cementitious materials (particularly portland cement mortar and concrete). A number of important prior investigations performed on the use of FRP waste in concrete and mortar are reviewed. The results from most of those investigations suggest that FRP aggregates significantly reduce the strength of cementitious materials with little significant effect on durability. Recommendations for future research in this area are provided for producing stronger mortars and concretes incorporating FRP production and end-of-life waste.

The Mechanical Property of Recycled Fiber Reinforced Polymer Composites by Superheated Steam

Fiber Reinforced Polymer (FRP) composites are used in many applications for their excellent strength-to-weight ratio. These properties are significant barriers for achieving the 3R concept (Recycle, Reuse, and Reduce). Inverse manufacturing is a recent technology that produces new materials and industrial goods from FRP waste based on life-cycle assessment (LCA), and it is expected to help solve the problems of 3R associated with FRP [1-. However, no effective recycling system of FRP has been established because of the cross-linked structure of thermosetting resin matrix and inorganic reinforcement fibers. To investigate the possibility of recycling and reusing both matrix and reinforcements, a project of preventing environmental deterioration was performed. In this study, a new decomposition method for recycling FRP waste by superheated steam was developed. Separation of the resin matrix and reinforcement fiber from the FRP was attempted, the FRP recycled from the separated fibers was remolded; this is called R-FRP.

Recycling of FRP composites: reusing fine GFRP waste in concrete mixtures

Fibre reinforced polymer (FRP) materials are being increasingly used in several applications, but especially in the construction and transportation industries. The composites industry is now producing a wide range of FRP products that include strengthening strips and sheets, reinforcing bars, structural profiles, sandwich panels, moulded planks and piping. The waste management of FRP materials, in particular those made with thermosetting resins, is a critical issue for the composites industry because these materials cannot be reprocessed. Therefore, most thermosetting FRP waste is presently sent to landfill, in spite of the significant environmental impact caused by disposing of it in this way. Because more and more waste is being produced throughout the life cycle of FRPs, innovative solutions are needed to manage it. This paper first presents a state-of-the-art review of the present alternatives available to manage FRP waste. It then describes an experimental study conducted on the technical feasibility of incorporating the fine waste generated during the manufacturing of glass fibre reinforced polymer (GFRP) composites in concrete mixtures. Tests were carried out to evaluate the fresh-state and hardened-state properties of concrete mixes in which between 0% and 20% of sand was replaced by GFRP fine waste. Although the incorporation of high proportions of GFRP waste was found to worsen concrete performance in terms of both mechanical and durability-related properties, it seems feasible to incorporate low proportions and reuse GFRP fine waste in concrete, particularly in non-structural applications such as architectural concrete or pavement slabs, where good mechanical properties are less important.