Recycled polymer fibers in concrete: a sustainability-focused review of environmental benefits and challenges

Abstract

The growing demand for sustainable and low-carbon construction materials has intensified interest in incorporating waste-derived materials into cement-based systems. Among these alternatives, recycled polymer fibers (RPFs) obtained from post-consumer plastics such as polyethylene terephthalate (PET) and polypropylene (PP) have attracted increasing attention due to their potential to simultaneously mitigate plastic waste pollution and reduce the environmental footprint of concrete. This review critically evaluates recycled polymer fiber-reinforced concrete (RPFRC) from a sustainability perspective, with particular emphasis on environmental impacts rather than solely on mechanical performance enhancement. A comprehensive assessment of recent literature indicates that the use of recycled polymer fibers can substantially reduce environmental burdens associated with conventional fiber production. Life cycle assessment (LCA) studies report that recycled polymer fibers may reduce energy consumption by approximately 40%–85% and decrease global warming potential by 25%–75% compared with virgin polymer fibers. In addition, the incorporation of recycled fibers reduces demand for virgin raw materials and supports circular economy strategies in construction materials. Despite these advantages, the environmental performance of RPFRC is strongly influenced by factors such as fiber processing methods, transportation distances, substitution efficiency, and system boundaries considered in LCA studies. Furthermore, variability in recycled fiber properties, lack of standardized specifications, and limited large-scale field validation remain important barriers to practical implementation. This review synthesizes current knowledge on the environmental performance of RPFRC, identifies key research gaps, and outlines future directions to improve sustainability assessment frameworks and facilitate the broader adoption of recycled polymer fibers in concrete applications.

1 Introduction

Concrete remains one of the most widely used construction materials worldwide and plays a central role in the development of modern infrastructure, including buildings, bridges, transportation networks, and hydraulic structures. Its widespread application is largely attributed to its durability, structural capacity, and relatively low cost (Ma et al., 2025). Nevertheless, the environmental implications of conventional concrete production have become a growing concern. In particular, cement manufacturing, which provides the binding phase in concrete, is responsible for approximately 7%–8% of global carbon dioxide (CO₂) emissions (Nejad et al., 2025). The regional distribution of global cement production in 2022 is shown in Figure 1, highlighting the dominance of certain regions, with China alone accounting for nearly 54% of global cement output (Guo et al., 2022).

FIGURE 1

The large-scale extraction of natural aggregates for concrete production contributes to ecosystem disturbance and resource depletion, while the manufacturing and transportation of construction materials consume considerable energy. These challenges have intensified the need for sustainable construction strategies to reduce the environmental footprint of concrete without compromising its structural performance. At the same time, the world is experiencing a rapidly escalating plastic waste crisis. Global plastic production has reached approximately 400 million tons annually, a significant portion of which ultimately accumulates in landfills, incineration facilities, or natural ecosystems (Javed et al., 2025). Among the most widely used polymers are polyethylene terephthalate (PET), commonly utilized in beverage bottles and containers, and polypropylene (PP), which is extensively used in packaging materials and textile products (Friedrich et al., 2005). As illustrated in Figure 2, plastic waste can be recycled and processed into polymer fibers, which may subsequently be incorporated into fiber-reinforced concrete, offering a promising pathway for both waste valorization and improved material functionality.

FIGURE 2

Plastics such as polyethylene terephthalate (PET) and polypropylene (PP) are characterized by high durability and resistance to biological and chemical degradation. While these properties make them valuable for industrial and consumer applications, they also create serious disposal challenges. The long-term persistence of plastic waste in the environment contributes to terrestrial pollution, marine contamination, and greenhouse gas emissions associated with degradation and incineration processes (Nicholson et al., 2021). Consequently, increasing attention has been directed toward diverting plastic waste from conventional disposal pathways and reutilizing it in value-added applications, including construction materials.

One promising strategy is to incorporate recycled polymer fibers into cementitious composites. Recycled polymer fibers (RPFs), typically derived from post-consumer or industrial plastic waste streams, have gained significant attention as sustainable reinforcement materials, with PET and PP fibers being among the most extensively investigated (Shen et al., 2012). Unlike virgin synthetic fibers, whose production requires additional petrochemical resources and energy, RPFs utilize existing waste materials and therefore help reduce environmental burdens associated with plastic disposal (Siddique et al., 2008). This approach aligns closely with circular economy principles, which emphasize resource efficiency, waste minimization, and the reintegration of end-of-life materials into productive systems.

Although the use of polymer fibers in concrete is not new, synthetic fibers such as polypropylene and nylon have long been used to enhance crack resistance, toughness, and post-cracking performance of cement-based materials (Signorini and Volpini, 2021). In this context, recycled polymer fibers represent an important link between plastic waste management and sustainable concrete production within a circular economy framework. The conceptual relationship between plastic waste recycling and fiber-reinforced concrete applications is illustrated schematically in Figure 3.

FIGURE 3

The transition from virgin synthetic fibers to recycled alternatives is increasingly aligned with global decarbonization and resource-efficiency strategies. The substitution of virgin fibers with recycled polyethylene terephthalate (PET) or polypropylene (PP) fibers can significantly reduce the embodied energy and greenhouse gas emissions associated with fiber production (Tay et al., 2024). Several life cycle assessment (LCA) studies have demonstrated that incorporating recycled polymer fibers into concrete can reduce carbon emissions, fossil fuel depletion, and cumulative energy demand compared with conventional concrete or systems reinforced with virgin fibers (Marinelli et al., 2021). These findings highlight the potential of recycled polymer fibers to contribute simultaneously to environmental sustainability and material performance.

In addition to reducing emissions, recycled polymer fibers also offer an effective way to address the growing global plastic waste problem. The incorporation of plastic waste streams, including PET bottles and PP packaging materials, into cement-based composites can significantly reduce the amount of plastic sent to landfills or incineration facilities (Cappucci et al., 2020). Considering that global concrete production exceeds 10 billion tons annually, even a partial replacement with recycled fibers could divert millions of tons of plastic waste from disposal routes (Meyer, 2009). Consequently, the use of recycled polymer fibers in concrete provides a promising large-scale recycling pathway that supports circular economy objectives and improves the environmental profile of construction materials.

Despite these advantages, several technical and practical challenges remain. One of the main limitations arises from the heterogeneous nature of recycled polymer fibers. Their geometry, aspect ratio, and mechanical properties may vary significantly depending on the waste source, recycling process, and cutting methods used during fiber production (Soni et al., 2024). Such variability complicates performance prediction and hinders the development of standardized material specifications. Furthermore, PET and PP fibers are inherently hydrophobic, which results in weak interfacial bonding with the hydrophilic cementitious matrix (Suksiripattanapong et al., 2022). Without surface modification or chemical treatment, insufficient fiber–matrix adhesion may reduce stress-transfer efficiency and limit the fibers’ crack-bridging capacity.

Another challenge concerns the adoption of recycled polymer fiber-reinforced concrete (RPFRC) in practical construction applications. Engineers and stakeholders often remain cautious about introducing new materials unless their long-term performance and durability are clearly demonstrated (Kim et al., 2008). Durability aspects such as freeze–thaw resistance, chloride penetration, and chemical attack require further systematic investigation when recycled fibers are used in cementitious composites (Bhogayata and Arora, 2018). Moreover, most existing studies remain limited to laboratory-scale investigations, while field-scale validation and long-term monitoring are still relatively scarce. This gap between experimental research and practical application highlights the need for closer collaboration between researchers, industry stakeholders, and policymakers to establish standardized guidelines and design recommendations for RPFRC (Bui et al., 2018).

Nevertheless, the potential environmental benefits of recycled polymer fiber-reinforced concrete continue to attract increasing research interest. The utilization of recycled polymer fibers directly contributes to several United Nations Sustainable Development Goals (SDGs), particularly those related to responsible consumption and production, climate action, and sustainable cities and communities (Kumar et al., 2021). In addition, green building certification systems such as Leadership in Energy and Environmental Design (LEED) and Building Research Establishment Environmental Assessment Method (BREEAM) encourage the use of recycled materials and low-carbon technologies in construction projects (Kuttima et al., 2025). These frameworks further support the integration of recycled fibers into sustainable building practices.

Recent studies have also explored various strategies to overcome the technical limitations associated with recycled polymer fibers. Surface modification techniques, including plasma treatment, alkali treatment, and nanomaterial coatings, have been investigated to enhance fiber–matrix interfacial bonding and improve mechanical performance (Lee et al., 2015). Furthermore, hybrid reinforcement strategies that combine recycled polymer fibers with natural fibers or supplementary cementitious materials have demonstrated promising potential to balance mechanical performance and environmental sustainability (Balea et al., 2021). Advances in characterization methods and modeling techniques have also provided new insights into fiber reinforcement mechanisms and the environmental performance of recycled fiber systems (Tawiah et al., 2016).

Despite these advances, a comprehensive evaluation focusing specifically on the environmental sustainability of recycled polymer fiber-reinforced concrete remains limited. Most previous studies have primarily concentrated on mechanical performance or durability aspects, while the broader environmental implications of recycled polymer fibers have received comparatively less attention. Therefore, a critical synthesis of the environmental performance, sustainability benefits, and remaining challenges associated with recycled polymer fibers in concrete is required.

Accordingly, this review aims to provide a comprehensive sustainability-oriented evaluation of recycled polymer fibers in cement-based composites. The study focuses on environmental aspects, including waste valorization, carbon footprint reduction, and life cycle assessment outcomes. In addition, the review identifies key challenges related to fiber variability, interfacial bonding, and standardization that may hinder large-scale implementation. By summarizing current knowledge and identifying future research needs, this study aims to provide guidance for researchers, engineers, and policymakers seeking to promote the adoption of recycled polymer fibers in sustainable concrete applications. As summarized in Table 1, recycled polymer fibers offer significant sustainability advantages through CO₂ emission reduction, plastic waste valorization, and support for circular economy strategies, while challenges remain regarding fiber heterogeneity, interfacial bonding, and standardization.

2 Sources, properties, and processing of recycled polymer fibers for concrete

2.1 Fiber sources

The use of recycled polymer fibers in cementitious composites relies primarily on identifying and collecting suitable plastic waste streams. Among the various polymer types, polyethylene terephthalate (PET) and polypropylene (PP) represent the most widely available and extensively studied sources for recycled fiber production. PET is typically obtained from post-consumer beverage bottles, food containers, and packaging films, whereas PP originates from packaging materials, textiles, automotive components, and consumer products (Marcelino et al., 2025; EPA, 2022).

Marcelino et al. (2025) reported that PET recycling in Brazil involves three main industrial actors: recyclers, which exclusively process PET waste (26%); integrators, which both recycle and utilize recycled PET (13%); and applicators, which only use recycled PET in manufacturing processes (61%). According to data from the Brazilian Association of the PET Industry (ABIPET), the recycling rate of PET packaging reached 56.4% in 2021, up 15.4 percentage points from 2019. The beverage packaging sector accounts for approximately 29% of recycled PET consumption, followed by the textile sector (25%) and solid packaging applications (17%).

These polymers also constitute a substantial portion of global municipal solid waste (MSW). According to the United States Environmental Protection Agency (EPA), approximately 35.7 million tons of plastic waste were generated in the United States in 2018, representing 12.2% of total MSW, with nearly 27 million tons disposed in landfills (EPA, 2022). Despite the large volume of plastic waste generated, only about 4.5% of plastic packaging is recycled, highlighting the need for alternative valorization strategies such as the use of recycled polymer fibers in construction materials.

Bajracharya et al. (2014) further reported that plastic waste accounts for approximately 10%–16% of municipal solid waste by weight in several industrialized countries, including Australia, the United Kingdom, and the United States. Due to their relatively low density, plastics occupy a disproportionately large volume within waste streams, creating significant waste management challenges.

2.2 Processing workflow

Municipal solid waste constitutes the primary source of PET and PP used for recycled fiber production. As illustrated in Figure 4, plastic waste is converted into recycled polymer fibers through a multi-stage processing pathway.

FIGURE 4

The recycling process typically begins with collection and sorting of plastic waste streams. PET bottles and packaging materials are separated from mixed waste using density-based separation methods, optical sorting technologies, or advanced sensor-based systems such as infrared spectroscopy and Raman spectroscopy (Ángeles-Hurtado et al., 2021). Ángeles-Hurtado et al. (2021) emphasized that effective plastic waste management systems are essential for improving recycling efficiency. In Mexico, for example, recycling activities provide income for more than 35,000 workers, and approximately 60% of PET bottles are recycled.

Following sorting, the plastic waste undergoes washing and cleaning processes to remove labels, adhesives, and other contaminants. The cleaned plastic is subsequently shredded into flakes, which are melted and extruded into continuous filaments before being cut into fibers of the desired length.

For polypropylene waste, mechanical recycling methods are typically used, involving shredding, granulation, and extrusion, followed by cutting of the extruded strands into discrete fibers (Burgada et al., 2021).

2.3 Key characteristics of recycled polymer fibers

Depending on the intended application, fibers may be produced in different geometric forms, such as straight, crimped, or fibrillated. Depending on the intended application, fibers may vary in geometry, including straight, crimped, or fibrillated forms, with lengths ranging from 6 mm to 60 mm and diameters between 0.01 mm and 0.5 mm. The physical and mechanical properties of recycled polymer fibers are crucial to their performance in concrete. PET fibers are characterized by relatively high tensile strength, ranging from 300 to 600 MPa, and an elastic modulus of 5–12 GPa (Guo and Ashida, 1993). PP fibers, while exhibiting lower tensile strength (150–400 MPa), offer superior chemical resistance and lower density (Kunugi, 1999). Both fibers are hydrophobic, which limits their interaction with the hydrophilic cement matrix (Wu and Qiu, 2022). This lack of affinity often results in weak interfacial bonding and limited stress transfer across cracks. To address this, researchers have investigated various surface modification techniques, such as alkali treatment, plasma treatment, or coating with nanomaterials, to enhance the fiber–matrix interface (El-Sayed and Abou-Taleb, 2023). Another important aspect of fiber performance is geometry. The aspect ratio (length-to-diameter ratio) of fibers influences their ability to bridge cracks, improve ductility, and control shrinkage. Short fibers (<12 mm) are generally effective for controlling plastic shrinkage cracking (Bertelsen et al., 2019), while longer fibers (20–50 mm) contribute more significantly to post-cracking toughness and flexural performance (Garg et al., 2021). However, excessively long fibers may lead to poor dispersion, fiber balling, and reduced workability of fresh concrete. Optimizing the balance between fiber length, volume fraction, and workability remains a critical challenge in designing recycled polymer fiber-reinforced concretes (Lopez-Manchado and Arroyo, 2001). Processing conditions also affect fiber quality. For example, mechanical recycling of PET often leads to polymer chain degradation due to repeated heating and cooling cycles (Kawai et al., 2019). This results in reduced tensile strength and stiffness compared to virgin PET fibers. Similarly, contamination from other plastics, such as polyvinyl chloride (PVC) or polyethylene (PE), can compromise the uniformity of recycled fibers (Maou et al., 2021).

2.4 Modification techniques for fiber–matrix interaction

To improve the interfacial bonding between recycled polymer fibers and the cement matrix, several surface modification techniques have been investigated. These methods aim to enhance fiber roughness, increase surface energy, and improve mechanical interlocking at the fiber–matrix interface.

Common modification techniques include alkali treatment, plasma treatment, and nanomaterial coatings, which have been shown to improve fiber–matrix adhesion and increase crack-bridging efficiency (Rashwan et al., 2023). In addition, hybrid reinforcement approaches combining recycled polymer fibers with natural fibers or supplementary cementitious materials have shown promising results in balancing mechanical performance with sustainability objectives (Signorini and Volpini, 2021).

Advanced characterization techniques and numerical modeling approaches are also being applied to better understand the mechanisms of fiber reinforcement and environmental performance (Shen et al., 2020).

Figure 5 illustrates the load–deflection responses of plain concrete and fiber-reinforced concrete containing short and long fibers. The plain concrete specimen exhibits brittle behavior, characterized by a sudden drop in load-carrying capacity immediately after reaching peak load. In contrast, incorporating fibers significantly enhances post-peak performance.

FIGURE 5

The mixture with short fibers shows improved peak load and a more gradual reduction in load after cracking; however, a noticeable drop remains due to limited crack-bridging capacity. On the other hand, the use of long fibers provides a more pronounced improvement in ductility and energy absorption capacity. The long fibers effectively bridge cracks, resulting in a sustained load-carrying capacity even at higher deflection levels.

2.5 Comparative environmental considerations

From an environmental perspective, producing recycled polymer fibers generally requires significantly less energy than producing virgin fibers. For instance, recycled PET fibers may require up to 60% less energy and generate approximately 30%–40% lower CO₂ emissions compared with virgin PET fibers (de Assis et al., 2024; Katre et al., 2024).

However, it should be noted that the present study does not include a detailed life-cycle inventory analysis of plastic waste collection, transportation, and processing. Therefore, the reported environmental benefits are based on generalized findings from previous LCA studies rather than a system-specific assessment.

In this context, the environmental advantages of recycled PET fibers should be interpreted with caution, as factors such as transportation distance, recycling technology, and processing efficiency may significantly influence the overall impact. Comprehensive life cycle assessment (LCA) studies are therefore essential for accurately evaluating the sustainability of recycled polymer fiber systems (Intini and Kühtz, 2011).

In addition to PET and PP, other recycled polymers such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), and nylon fibers have also been explored for cementitious applications, although to a lesser extent (Laria et al., 2023; Ferr et al., 2025). Furthermore, recent research has investigated hybrid fiber systems that combine recycled and virgin fibers in order to balance mechanical performance and sustainability benefits (Singh and Demirsöz, 2022).

To provide a comprehensive overview of the environmental characteristics of recycled polymer fibers, Table 2 summarizes the main fiber types, waste sources, energy demand, potential CO₂ emission reductions, and key limitations reported in the literature.

3 Environmental benefits of recycled polymer fiber-reinforced concrete

3.1 Life cycle assessment framework

The integration of recycled polymer fibers into cement-based materials has attracted growing attention due to its potential environmental advantages. Recycled polymer fiber-reinforced concrete (RPFRC) utilizes plastic waste streams such as polyethylene terephthalate (PET) and polypropylene (PP) as reinforcing elements, thereby providing an opportunity to simultaneously address plastic waste management and reduce the environmental footprint of construction materials. The reuse of polymer waste in cementitious composites contributes to resource efficiency and promotes the development of more sustainable material cycles in the construction industry (Xanthopoulou et al., 2023).

To quantitatively evaluate the environmental implications of RPFRC, life cycle assessment (LCA) has become an essential analytical tool. LCA enables a systematic assessment of environmental impacts associated with materials across their entire life cycle, including raw material extraction, processing, manufacturing, transportation, construction, service life, and end-of-life stages. In the context of fiber-reinforced concrete, LCA studies commonly examine environmental indicators such as global warming potential (GWP), cumulative energy demand, fossil resource depletion, and waste reduction potential.

When recycled fibers are used instead of virgin polymer fibers, several stages of the life cycle are directly affected. In particular, the substitution of virgin polymer production with recycling processes can substantially reduce the environmental burdens associated with petrochemical feedstocks and energy-intensive manufacturing operations. As a result, RPFRC has been increasingly investigated as a strategy to reduce the environmental impacts of concrete production while simultaneously improving waste management practices.

3.2 Core environmental benefits

3.2.1 Carbon footprint reduction

One of the most widely recognized environmental benefits of recycled polymer fiber-reinforced concrete is its potential to reduce greenhouse gas emissions associated with the production of fibers and concrete (Balea et al., 2021). The production of virgin synthetic fibers, particularly polypropylene (PP), requires substantial energy and relies heavily on petrochemical feedstocks, resulting in significant carbon emissions during manufacturing (Aslani and Nejadi, 2013).

Replacing virgin polymer fibers with recycled alternatives can significantly reduce these emissions. Several studies have reported that recycled PET fibers provide substantial environmental advantages compared with virgin PET production. For example, recycled PET fibers have been shown to achieve energy savings ranging from 40% to 85% and reductions in global warming potential (GWP) of approximately 25%–75% relative to virgin polymer production (Butyrin et al., 2024). These reductions primarily result from avoiding the energy-intensive polymerization processes associated with virgin plastic manufacturing.

Figure 6 presents the normalized CO₂ emissions of the investigated mortar systems expressed as kgCO₂ per MPa of compressive strength, enabling a performance-based comparison. Unlike the previous version, which provided only percentage values, the revised figure incorporates normalization based on mechanical performance, enabling a more realistic assessment of environmental efficiency. In addition, variability ranges (±5%) are included to reflect the inherent uncertainty associated with literature-based data. As shown in the figure, incorporating silica fume (SF) and coconut shell activated carbon (CSAC) results in a progressive reduction in normalized CO₂ emissions, indicating an improved balance between environmental impact and mechanical performance. This trend highlights the effectiveness of these materials in enhancing the sustainability of mortar systems when evaluated using performance-oriented indicators.

FIGURE 6

It should be noted that the mixtures labeled as K0–K8 in Figure 6 do not correspond to a single experimental dataset but represent a conceptual classification derived from literature findings. In this framework, SF content is considered constant (≈10%), while CSAC content increases progressively to reflect commonly reported replacement ranges. The normalized CO₂ values (kgCO₂/MPa) are used to provide a performance-based environmental comparison.

3.2.2 Energy savings

In addition to reducing carbon emissions, recycled polymer fibers can significantly lower the energy demand associated with material production. The manufacturing of virgin polymer fibers involves multiple energy-intensive stages, including polymer synthesis, melt processing, extrusion, and fiber formation. These processes require substantial energy inputs and contribute to the overall environmental footprint of fiber-reinforced concrete.

In contrast, recycled polymer fibers are typically produced through mechanical recycling processes that involve collecting, sorting, washing, shredding, and extruding plastic waste. These recycling operations generally require considerably less energy than virgin polymer production.

As illustrated in Figure 6, virgin polymer fibers exhibit the highest energy consumption and CO₂ emissions due to the intensive petrochemical processes involved. Recycled polymer fibers produced through mechanical recycling routes demonstrate significantly lower environmental impacts. Although chemical recycling technologies can restore polymer quality, they typically involve additional processing stages and therefore may require higher energy inputs compared with mechanical recycling methods. Consequently, the environmental performance of recycled fibers depends strongly on the recycling technology employed and the associated processing conditions.

3.2.3 Waste diversion and resource recovery

The incorporation of recycled polymer fibers into concrete also helps reduce the environmental impacts associated with plastic waste disposal. According to data reported by the Organisation for Economic Co-operation and Development (OECD), global plastic waste generation increased from 156 Mt in 2000 to approximately 353 Mt in 2019 (Sonke et al., 2025). A significant portion of this waste is disposed of through landfilling, incineration, or uncontrolled dumping, leading to environmental pollution and resource loss.

Incorporating recycled plastic materials into concrete provides a high-volume application for waste valorization. Considering the enormous global demand for concrete, estimated at approximately 30 billion tons per year, even small substitution rates of recycled fibers could redirect millions of tons of plastic waste from landfills into construction materials (Uutel et al., 1990). Such applications transform plastic waste streams into value-added engineering materials and contribute to more sustainable waste management strategies.

3.3 Synergistic environmental benefits

Beyond the direct environmental benefits related to carbon emission reductions, energy savings, and waste diversion, recycled polymer fiber-reinforced concrete also provides several indirect environmental advantages. One of the most important contributions is its alignment with circular economy principles, which emphasize resource efficiency, waste minimization, and the reintegration of end-of-life materials into productive applications (Aldosari et al., 2024; Gracida-Alvarez et al., 2023).

By incorporating recycled PET and PP fibers into concrete structures, plastic materials that would otherwise enter waste streams can be immobilized within durable infrastructure systems. Due to the long service life of concrete structures, recycled polymers embedded within the cement matrix can remain encapsulated for decades, effectively preventing their release into the environment (Venkatachalam et al., 2022).

The environmental advantages of RPFRC also support broader sustainability initiatives. For instance, the reuse of plastic waste and the reduction of embodied carbon contribute to the objectives of the United Nations Sustainable Development Goals (SDGs), particularly Goal 12 (responsible consumption and production) and Goal 13 (climate action) (Chatziparaskeva et al., 2022). Similarly, green building certification systems such as LEED and BREEAM encourage the use of recycled materials and low-carbon construction technologies, which can further promote the adoption of RPFRC in sustainable construction projects (Przybek, 2025).

In addition, recycled polymer fibers can help conserve natural resources by partially replacing resource-intensive materials such as virgin synthetic fibers or steel fibers (Mastali et al., 2018). However, the environmental benefits of recycled fibers must be evaluated alongside the impacts associated with recycling processes themselves. Activities such as collection, sorting, cleaning, and processing of plastic waste require energy and may generate emissions (Valverde-Burneo et al., 2025). Therefore, comprehensive life cycle assessment studies are necessary to evaluate the balance between recycling benefits and processing impacts (Das et al., 2021).

Another indirect environmental benefit of RPFRC relates to improved durability and service life of concrete structures (Hahladakis and Iacovidou, 2019). Fiber reinforcement helps control shrinkage cracking and limits the propagation of microcracks, thereby reducing the ingress of aggressive agents such as chlorides and sulfates. Although improvements in mechanical strength may vary depending on fiber type and dosage, enhanced crack control can delay deterioration mechanisms and extend the service life of structures. Consequently, longer service life leads to reduced maintenance requirements, lower material consumption, and decreased life-cycle emissions (Ahmad et al., 2022).

The key environmental drivers, circular-economy contributions, certification relevance, and life-cycle implications of recycled polymer fiber-reinforced concrete are summarized in Table 3.

4 Technical and application challenges of recycled polymer fiber-reinforced concrete

Although recycled polymer fiber-reinforced concrete (RPFRC) offers considerable environmental and sustainability advantages, several technical and practical challenges still limit its widespread adoption in construction practice (Hamad et al., 2013). These limitations arise mainly from the variability of recycled materials, weak interfacial bonding between polymer fibers and cementitious matrices, uncertainties in engineering performance, and the absence of standardized specifications for recycled fiber applications (Ev et al., 2002). A comprehensive understanding of these challenges is essential for improving the reliability, scalability, and practical implementation of RPFRC in structural and non-structural concrete systems (Gu and Ozbakkaloglu, 2016).

4.1 Material-level challenges

4.1.1 Fiber performance variation

One of the primary challenges associated with recycled polymer fibers is the variability in their mechanical and geometric properties. Unlike virgin synthetic fibers, which are produced under controlled industrial conditions, recycled fibers originate from diverse waste streams with different chemical compositions, manufacturing histories, and degradation levels. As a result, recycled fibers often exhibit irregular geometries, varying aspect ratios, and inconsistent tensile strength and stiffness (Rebeiz et al., 1993).

Differences in recycling processes can further influence fiber properties. Mechanical recycling, which involves shredding and extrusion of plastic waste, may lead to polymer chain degradation due to repeated thermal cycles. Consequently, recycled fibers may demonstrate reduced mechanical performance compared with their virgin counterparts. This variability complicates predicting fiber performance in concrete mixtures and introduces uncertainties in mix design optimization and structural reliability (Dehghan et al., 2017).

4.1.2 Weak interface bonding

Recycled polymer fibers often exhibit relatively weak interfacial bonding with the cementitious matrix, which represents a critical limitation for their effective reinforcement performance (Jo et al., 2008). In general, polymer-based fibers are inherently hydrophobic and chemically inert, which reduces their compatibility with the hydrophilic cement paste. Moreover, the relatively smooth surface texture of many recycled fibers further limits mechanical interlocking with the surrounding matrix (Kou and Poon, 2013). The weak interfacial bonding between recycled polymer fibers and the cementitious matrix is mainly attributed to their hydrophobic surface and limited mechanical interlocking with the surrounding matrix, as illustrated in Figure 7.

FIGURE 7

Weak fiber–matrix adhesion can reduce the efficiency of stress transfer across cracks and limit the fibers’ crack-bridging capacity. Consequently, although recycled polymer fibers may improve ductility and crack resistance, their influence on enhancing compressive and flexural strength is often limited (Shourijeh et al., 2022). To address this limitation, several surface modification techniques have been investigated, including alkali treatment, plasma activation, and nanocoating, to increase surface roughness and improve fiber–matrix interfacial bonding (Farhangi and Karakouzian, 2020).

4.1.3 Impact on engineering performance

The incorporation of recycled polymer fibers may also influence several engineering properties of fresh and hardened concrete. From a fresh concrete perspective, high fiber dosages or long fiber lengths may reduce workability and cause fiber clustering or balling during mixing. This can result in non-uniform fiber dispersion and increased mixing energy requirements (Ulu et al., 2022).

The potential influence of recycled polymer fibers on fresh and hardened concrete properties is schematically illustrated in Figure 8.

FIGURE 8

In hardened concrete, the effects of recycled fibers on mechanical properties can vary depending on fiber type, dosage, and geometry. While improvements in crack control and post-cracking ductility are frequently reported, the influence on compressive and flexural strength remains inconsistent across different studies. Furthermore, the long-term durability performance of RPFRC requires further investigation. Environmental exposure conditions, such as freeze–thaw cycles, chloride penetration, sulfate attack, and chemical corrosion, may affect the long-term behavior of recycled polymer fibers embedded in the cement matrix (Harle, 2024).

4.1.4 Barriers to standardization and scaling

Another important barrier to the large-scale adoption of RPFRC is the lack of standardized specifications and design guidelines for recycled polymer fibers in concrete applications. While steel fibers and virgin synthetic fibers are covered by existing international standards, recycled polymer fibers are not yet supported by comprehensive material quality classifications or structural design recommendations (Jafari et al., 2018).

The absence of standardized testing protocols and material specifications creates uncertainties for engineers and practitioners when designing concrete mixtures incorporating recycled fibers. In addition, large-scale field applications and long-term performance data remain relatively limited, as most studies are currently confined to laboratory-scale experiments. Overcoming these barriers requires coordinated efforts among researchers, industry stakeholders, and regulatory organizations to establish standardized guidelines, quality-control procedures, and demonstration projects that validate the performance of recycled polymer fiber-reinforced concrete under real-world conditions (Odeh et al., 2025). The main standardization and scaling challenges of RPFRC and their possible solutions are summarized in Table 4.

5 Challenges and limitations of recycled polymer fiber-reinforced concrete

Although the integration of recycled polymer fibers (RPFs) into concrete offers clear sustainability advantages, several technical and practical challenges still limit their broader implementation in construction. These limitations are mainly due to material variability, weak fiber–matrix interactions, processing difficulties, and the absence of standardized testing and design guidelines (Suchorab et al., 2020). Understanding these constraints is essential for developing strategies to improve the reliability and practical adoption of recycled polymer fiber-reinforced concrete (RPFRC) (Sasi et al., 2024).

One of the key challenges arises from the heterogeneity of recycled fibers. Unlike virgin synthetic fibers produced under controlled industrial conditions, recycled fibers originate from diverse waste streams with varying chemical compositions, contamination levels, and mechanical properties (de Assis et al., 2024). For example, PET bottles may differ in additives and molecular orientation depending on manufacturing processes and intended applications (Lee et al., 2025), while recycled PP waste can originate from textiles, packaging, or automotive components with distinct mechanical characteristics (Frankenbach et al., 2025). Consequently, recycled fibers often exhibit irregular geometries, inconsistent aspect ratios, and variable tensile strengths, which complicates mix design optimization and may result in inconsistent performance in both laboratory and field applications (Seifali Abbas-Abadi et al., 2025).

Another important limitation is the relatively weak interfacial bonding between polymer fibers and the cementitious matrix. Both PET and PP fibers are hydrophobic and chemically inert, which reduces their affinity with the hydrophilic cement paste and limits efficient stress transfer (Marković et al., 2025). Smooth fiber surfaces may further reduce crack-bridging effectiveness and restrict improvements in mechanical strength (El-Messiry and Eid, 2025). As a result, recycled fibers generally contribute more to crack control and ductility than to enhancing compressive or flexural strength (Liu et al., 2025).

Several mitigation strategies have been proposed to overcome these challenges. Surface modification methods such as alkali treatment, plasma activation, and nanocoatings have been shown to improve fiber–matrix interactions and enhance stress-transfer mechanisms (Laib et al., 2025). However, these treatments may increase processing complexity, energy demand, and cost, which must be carefully considered when evaluating the overall sustainability benefits of recycled fibers (Schultz et al., 2025). Lessons from other recycled materials used in concrete, such as recycled aggregates and construction waste, suggest that standardized processing procedures, improved quality control, and optimized mix design approaches can significantly reduce variability and improve performance consistency.

Workability issues also remain an important practical concern. Recycled fibers, particularly when used at high dosages or with large aspect ratios, may lead to fiber agglomeration and balling during mixing (Shater et al., 2025). Optimizing fiber content, adjusting mixing procedures, and using suitable admixtures may help mitigate these issues and improve fiber dispersion within the cementitious matrix.

The main technical and practical challenges associated with recycled polymer fibers in concrete, together with their underlying causes and potential mitigation strategies, are summarized in Table 5.

As illustrated in Figure 9, alkali treatment, plasma activation, and nano-coating represent the most common approaches to improve fiber–matrix interactions, each contributing to enhanced interfacial bonding.

FIGURE 9

The incorporation of recycled polymer fibers may also influence the workability of fresh concrete mixtures. Fiber agglomeration and balling can reduce flowability, increase mixing energy requirements, and lead to non-uniform fiber dispersion, particularly in mixtures requiring high workability such as self-compacting concrete. Adjusting fiber dosage, optimizing mixing procedures, and employing suitable chemical admixtures can partially mitigate these issues; however, such measures may introduce additional complexity into the mix design process (Hou et al., 2025).

Another important barrier to practical implementation is the absence of standardized specifications and quality control procedures for recycled polymer fibers. While steel fibers and virgin synthetic fibers are covered by established standards such as ASTM, EN, or ISO, recycled polymer fibers currently lack universally accepted material classifications and testing guidelines (Khan and Abbas, 2025). This limitation limits engineers’ confidence in designing with recycled polymer fiber-reinforced concrete (RPFRC), as performance predictions remain uncertain without standardized evaluation methods. Similar challenges were previously observed during the early adoption of other recycled materials in concrete, such as recycled aggregates, where the development of standardized processing and testing procedures significantly improved reliability and acceptance.

Furthermore, large-scale field validation of RPFRC remains limited, as most available studies are based on laboratory-scale experiments (Deutz et al., 2025). Demonstration projects and pilot applications could therefore play an important role in evaluating long-term durability, structural performance, and constructability under real service conditions. Such initiatives may also help bridge the gap between academic research and practical implementation.

Economic and perception-related factors also influence the adoption of recycled polymer fibers. Although recycled fibers are typically less expensive than virgin fibers, variability in material quality may require additional processing, sorting, or quality assurance procedures, which can increase overall costs (Seifali Abbas-Abadi et al., 2025). In addition, skepticism within the construction sector regarding the durability and reliability of waste-derived materials can slow their acceptance in structural applications (Jaczynska and Mehta, 2025). Overcoming these barriers will require not only improved technical performance but also robust experimental data, successful pilot projects, and supportive regulatory frameworks (Li et al., 2024).

The main technical challenges and potential mitigation strategies associated with recycled polymer fiber-reinforced concrete are summarized in Table 6.

Although recycled polymer fiber-reinforced concrete (RPFRC) offers important environmental and sustainability advantages, several technical and practical challenges still limit its large-scale implementation in construction practice. These limitations arise from material variability, weak fiber–matrix interaction, uncertainties in engineering performance, and the lack of standardized design approaches. To better understand the balance between environmental benefits and engineering constraints, the key issues reported in the literature are summarized through benefit–challenge comparison and trade-off analyses. The environmental advantages of recycled polymer fiber-reinforced concrete are often accompanied by several technical and practical challenges that must be considered during material design and application. While the use of recycled polymer fibers contributes to waste reduction, resource efficiency, and lower carbon emissions, these benefits may also introduce certain limitations related to material variability and performance consistency. In particular, differences in fiber geometry, surface characteristics, and recycling processes can influence fiber dispersion and mechanical behavior in concrete mixtures. Moreover, the hydrophobic nature of polymer fibers and the lack of standardized material classifications may create additional uncertainties in engineering applications. Addressing these issues requires careful optimization of fiber dosage, improvement of fiber–matrix bonding, and the development of appropriate design guidelines. The relationship between the environmental benefits of recycled polymer fibers and the associated technical challenges is summarized in Table 7.

The application of recycled polymer fibers in concrete also involves several important trade-offs between environmental benefits, engineering performance, and practical implementation. While recycled fibers can improve crack control and contribute to sustainability goals, increasing fiber content may negatively affect workability and mixing efficiency. Similarly, surface modification techniques can enhance fiber–matrix bonding and mechanical performance, but these treatments may introduce additional processing steps and environmental costs. In addition, although recycled fibers support circular economy principles by utilizing plastic waste, variability in fiber properties may introduce uncertainty into concrete performance. Balancing these competing factors is therefore essential to achieve both environmental and engineering benefits in recycled polymer fiber-reinforced concrete systems. The key trade-offs associated with the use of recycled polymer fibers in concrete are summarized in Table 8.

6 Conclusion and future outlook

This review has critically examined the role of RPFs, particularly PET and PP, in enhancing the sustainability of cementitious composites. While conventional research on fiber-reinforced concrete has largely emphasized mechanical and durability aspects, this study placed primary focus on the environmental benefits and challenges of using recycled fibers. By synthesizing current findings, the review demonstrated that recycled fibers help reduce the carbon footprint of concrete, divert plastic waste from landfills, and support circular economy practices. At the same time, technical, economic, and standardization challenges were identified, highlighting areas requiring further research to achieve widespread adoption.

References

• 1

  AhmadJ.MajdiA.Babeker ElhagA.DeifallaA. F.SoomroM.IsleemH. F.et al (2022). A step towards sustainable concrete with substitution of plastic waste in concrete: overview on mechanical, durability and microstructure analysis. Crystals12 (7), 944. 10.3390/cryst12070944

  • CrossRef
  • Google Scholar
  • View reference in article

• 2

  AldosariS. M.AlOtaibiB. M.AlblalaihidK. S.AldoihiS. A.AlOgabK. A.AlsalehS. S.et al (2024). Mechanical recycling of carbon fiber-reinforced polymer in a circular economy. Polymers16 (10), 1363. 10.3390/polym16101363

  • Pubmed Abstract
  • CrossRef
  • Google Scholar
  • View reference in article

• 3

  Ángeles-HurtadoL. A.Rodríguez-ReséndizJ.Salazar-ColoresS.Torres-SalinasH.Sevilla-CamachoP. Y. (2021). Viable disposal of post-consumer polymers in Mexico: a review. Front. Environ. Sci.9. 10.3389/fenvs.2021.749775

  • CrossRef
  • Google Scholar
  • View reference in article

• 4

  AslaniF.NejadiS. (2013). Self-compacting concrete incorporating steel and polypropylene fibers: compressive and tensile strengths, moduli of elasticity and rupture, compressive stress–strain curve, and energy dissipated under compression. Compos. Part B Eng.53, 121–133. 10.1016/j.compositesb.2013.04.044

  • CrossRef
  • Google Scholar
  • View reference in article

• 5

  BajracharyaR. M.ManaloA. C.KarunasenaW.LauK. T. (2014). An overview of mechanical properties and durability of glass-fibre reinforced recycled mixed plastic waste composites. Mater. Des. (1980-2015)62, 98–112. 10.1016/j.matdes.2014.04.081

  • CrossRef
  • Google Scholar
  • View reference in article

• 6

  BaleaA.FuenteE.MonteM. C.BlancoA.NegroC. (2021). Recycled fibers for sustainable hybrid fiber cement based material: a review. Materials14 (9), 2408. 10.3390/ma14092408

  • Pubmed Abstract
  • CrossRef
  • Google Scholar
  • View reference in article

• 7

  BertelsenI. M. G.OttosenL. M.FischerG. (2019). Quantitative analysis of the influence of synthetic fibres on plastic shrinkage cracking using digital image correlation. Constr. Build. Mater.199, 124–137. 10.1016/j.conbuildmat.2018.11.268

  • CrossRef
  • Google Scholar
  • View reference in article

• 8

  BhogayataA. C.AroraN. K. (2018). Workability, strength, and durability of concrete containing recycled plastic fibers and styrene-butadiene rubber latex. Constr. Build. Mater.180, 382–395. 10.1016/j.conbuildmat.2018.05.175

  • CrossRef
  • Google Scholar
  • View reference in article

• 9

  BuiN. K.SatomiT.TakahashiH. (2018). Recycling woven plastic sack waste and PET bottle waste as fiber in recycled aggregate concrete: an experimental study. Waste Management78, 79–93. 10.1016/j.wasman.2018.05.035

  • Pubmed Abstract
  • CrossRef
  • Google Scholar
  • View reference in article

• 10

  BurgadaF.FagesE.Quiles-CarrilloL.LascanoD.Ivorra-MartinezJ.ArrietaM. P.et al (2021). Upgrading recycled polypropylene from textile wastes in wood plastic composites with short hemp fiber. Polymers13 (8), 1248. 10.3390/polym13081248

  • Pubmed Abstract
  • CrossRef
  • Google Scholar
  • View reference in article

• 11

  ButyrinA. Y.ShnainA. H.ReddyG. K.SinghT.PandeyA. K.SinghN.et al (2024). Assessing the environmental impact of plastic waste using life cycle assessment. E3S Web Conf.581, 01010.

  • Google Scholar
  • View reference in article

• 12

  CappucciG. M.AvolioR.CarfagnaC.CoccaM.GentileG.ScarpelliniS.et al (2020). Environmental life cycle assessment of the recycling processes of waste plastics recovered by landfill mining. Waste Manag.118, 68–78. 10.1016/j.wasman.2020.07.048

  • Pubmed Abstract
  • CrossRef
  • Google Scholar
  • View reference in article

• 13

  ChatziparaskevaG.PapamichaelI.VoukkaliI.LoiziaP.SourkouniG.ArgirusisC.et al (2022). End-of-life of composite materials in the framework of the circular economy. Microplastics1 (3), 377–392. 10.3390/microplastics1030028

  • CrossRef
  • Google Scholar
  • View reference in article

• 14

  DasS.LiangC.DunnJ. B. (2021). “Life cycle assessment of polymers and their recycling,” in Circular economy of polymers: topics in recycling technologies (American Chemical Society), 143–170.

  • Google Scholar
  • View reference in article

• 15

  de AssisH. J. B.da Silva BezerraA. C.de PaulaJ. N.MoraviaW. G. (2024). Utilization of recycled synthetic fibers in concrete with a focus on structural properties enhancement: a critical literature review. Discov. Mater.4 (1), 77. 10.1007/s43939-024-00150-1

  • CrossRef
  • Google Scholar
  • View reference in article

• 16

  DehghanA.PetersonK.ShvarzmanA. (2017). Recycled glass fiber reinforced polymer additions to Portland cement concrete. Constr. Build. Mater.146, 238–250. 10.1016/j.conbuildmat.2017.04.011

  • CrossRef
  • Google Scholar
  • View reference in article

• 17

  DeutzD. B.BoschA. F.BaptistaD. E.van VeenE. S.PlatenkampD. J.JansenH. P. (2025). Non-contact non-destructive testing methods for large-scale carbon fiber-reinforced polymer aircraft parts. Eng. Proc.90 (1), 25.

  • Google Scholar
  • View reference in article

• 18

  El-MessiryM.EidE. S. M. (2025). Comprehensive analysis of crack resistance and failure modes in cement concrete reinforced with recycled water bottle fibers: influence of fiber diameter, length, and content under compression. J. Industrial Text.55, 15280837251342568. 10.1177/15280837251342568

  • CrossRef
  • Google Scholar
  • View reference in article

• 19

  El-SayedH.Abou-TalebM. (2023). Polypropylene fabric of durable hydrophilic character using plasma-mediated surface coating with keratin. J. Adhesion Sci. Technol.37 (24), 3687–3701. 10.1080/01694243.2023.2218534

  • CrossRef
  • Google Scholar
  • View reference in article

• 20

  EPA (2022). Facts and figures about materials. Waste Recycl. Plastics Material-Specific Data. Available online at: https://www.epa.gov/facts-and-figures-about-materials-waste-and-recycling/plastics-material-specific-data (Accessed January 3, 2022).

  • Google Scholar
  • View reference in article

• 21

  EvstatievM.FakirovS.KrastevaB.FriedrichK.CovasJ. A.CunhaA. M. (2002). Recycling of poly (ethylene terephthalate) as polymer‐polymer composites. Polym. Eng. and Sci.42 (4), 826–835. 10.1002/pen.10994

  • CrossRef
  • Google Scholar
  • View reference in article

• 22

  FarhangiV.KarakouzianM. (2020). Effect of fiber reinforced polymer tubes filled with recycled materials and concrete on structural capacity of pile foundations. Appl. Sci.10 (5), 1554. 10.3390/app10051554

  • CrossRef
  • Google Scholar
  • View reference in article

• 23

  FerreiraR. S.JesusG. A.MonteiroJ. P.MartinsA. F.TessariR. K.BonaféE. G. (2025). Eco-friendly and cost-effective high-density polyethylene-based composites: optimizing wood–plastic composites for enhanced performance. ACS Omega10 (7), 6437–6445. 10.1021/acsomega.4c06422

  • Pubmed Abstract
  • CrossRef
  • Google Scholar
  • View reference in article

• 24

  FrankenbachL. A.LukoschekS.KruppkeI.CherifC. (2025). Multifilament spinning of mechanically recycled polypropylene from post-consumer sources for a circular economy in textile applications. Sci. Rep.15 (1), 14047. 10.1038/s41598-025-98375-4

  • Pubmed Abstract
  • CrossRef
  • Google Scholar
  • View reference in article

• 25

  FriedrichK.EvstatievM.FakirovS.EvstatievO.IshiiM.HarrassM. (2005). Microfibrillar reinforced composites from PET/PP blends: processing, morphology and mechanical properties. Compos. Sci. Technol.65 (1), 107–116. 10.1016/j.compscitech.2004.06.008

  • CrossRef
  • Google Scholar
  • View reference in article

• 26

  GargM.AzarsaP.GuptaR. (2021). Self-healing potential and post-cracking tensile behavior of polypropylene fiber-reinforced cementitious composites. J. Compos. Sci.5 (5), 122. 10.3390/jcs5050122

  • CrossRef
  • Google Scholar
  • View reference in article

• 27

  Gracida-AlvarezU. R.XuH.BenavidesP. T.WangM.HawkinsT. R. (2023). Circular economy sustainability analysis framework for plastics: application for poly (ethylene terephthalate)(PET). ACS Sustain. Chem. and Eng.11 (2), 514–524. 10.1021/acssuschemeng.2c04626

  • CrossRef
  • Google Scholar
  • View reference in article

• 28

  GuL.OzbakkalogluT. (2016). Use of recycled plastics in concrete: a critical review. Waste Manag.51, 19–42. 10.1016/j.wasman.2016.03.005

  • Pubmed Abstract
  • CrossRef
  • Google Scholar
  • View reference in article

• 29

  GuoW.AshidaM. (1993). Mechanical properties of PET short fiber–polyester thermoplastic elastomer composites. J. Applied Polymer Science49 (6), 1081–1091. 10.1002/app.1993.070490615

  • CrossRef
  • Google Scholar
  • View reference in article

• 30

  GuoZ.BaiX.LiuS.LuoL.HaoY.LvY.et al (2022). Heterogeneous variations on historical and future trends of CO2 and multiple air pollutants from the cement production process in China: emission inventory, spatial–temporal characteristics, and scenario projections. Environ. Sci. and Technol.56 (20), 14306–14314. 10.1021/acs.est.2c04445

  • Pubmed Abstract
  • CrossRef
  • Google Scholar
  • View reference in article

• 31

  HahladakisJ. N.IacovidouE. (2019). An overview of the challenges and trade-offs in closing the loop of post-consumer plastic waste (PCPW): focus on recycling. J. Hazardous Materials380, 120887. 10.1016/j.jhazmat.2019.120887

  • Pubmed Abstract
  • CrossRef
  • Google Scholar
  • View reference in article

• 32

  HamadK.KaseemM.DeriF. (2013). Recycling of waste from polymer materials: an overview of the recent works. Polym. Degradation Stability98 (12), 2801–2812. 10.1016/j.polymdegradstab.2013.09.025

  • CrossRef
  • Google Scholar
  • View reference in article

• 33

  HarleS. M. (2024). Durability and long-term performance of fiber reinforced polymer (FRP) composites: a review. Structures60, 105881. 10.1016/j.istruc.2024.105881

  • CrossRef
  • Google Scholar
  • View reference in article

• 34

  HouD.ZhangX.ZhangK.ZhangX.BaoM.JinL.et al (2025). Optimizing lightweight UHPC through the synergy of lightweight aggregate, filler, and polymer fiber via response surface methodology. Constr. Build. Mater.463, 140104. 10.1016/j.conbuildmat.2025.140104

  • CrossRef
  • Google Scholar
  • View reference in article

• 35

  IntiniF.KühtzS. (2011). Recycling in buildings: an LCA case study of a thermal insulation panel made of polyester fiber, recycled from post-consumer PET bottles. International Journal Life Cycle Assessment16 (4), 306–315. 10.1007/s11367-011-0267-9

  • CrossRef
  • Google Scholar
  • View reference in article

• 36

  JaczynskaK.MehtaS. (2025). Industrialization of post-consumer textile waste recycling (PCTW)-hope vs hype. Circular Econ. Sustain.5, 1–30. 10.1007/s43615-025-00657-6

  • CrossRef
  • Google Scholar
  • View reference in article

• 37

  JafariK.TabatabaeianM.JoshaghaniA.OzbakkalogluT. (2018). Optimizing the mixture design of polymer concrete: an experimental investigation. Constr. Build. Mater.167, 185–196. 10.1016/j.conbuildmat.2018.01.191

  • CrossRef
  • Google Scholar
  • View reference in article

• 38

  JavedM. H.AhmadA.RehanM.MusharavatiF.NizamiA. S.KhanM. I. (2025). Advancing sustainable energy: environmental and economic assessment of plastic waste gasification for syngas and electricity generation using life cycle modeling. Sustainability17 (3), 1277. 10.3390/su17031277

  • CrossRef
  • Google Scholar
  • View reference in article

• 39

  JoB. W.ParkS. K.ParkJ. C. (2008). Mechanical properties of polymer concrete made with recycled PET and recycled concrete aggregates. Constr. Build. Mater.22 (12), 2281–2291. 10.1016/j.conbuildmat.2007.10.009

  • CrossRef
  • Google Scholar
  • View reference in article

• 40

  KatreR.BhavsarK.SalaamA.RaoG. M.RjA.SinglaA.et al (2024). Assessing eco-friendly alternatives: composite fibers and recycled plastics for sustainable impact and efficiency. E3S Web Conf.552, 01089. 10.1051/e3sconf/202455201089

  • CrossRef
  • Google Scholar
  • View reference in article

• 41

  KawaiF.KawabataT.OdaM. (2019). Current knowledge on enzymatic PET degradation and its possible application to waste stream management and other fields. Appl. Microbiology Biotechnology103 (11), 4253–4268. 10.1007/s00253-019-09717-y

  • Pubmed Abstract
  • CrossRef
  • Google Scholar
  • View reference in article

• 42

  KhanM. I.AbbasY. M. (2025). Synergistic enhancement of high-strength concrete’s mechanical strength through the utilization of steel, synthetic, and hybrid fiber systems. Int. J. Concr. Struct. Mater.19 (1), 18. 10.1186/s40069-024-00756-y

  • CrossRef
  • Google Scholar
  • View reference in article

• 43

  KimJ. H. J.ParkC. G.LeeS. W.LeeS. W.WonJ. P. (2008). Effects of the geometry of recycled PET fiber reinforcement on shrinkage cracking of cement-based composites. Compos. Part B Eng.39 (3), 442–450. 10.1016/j.compositesb.2007.05.001

  • CrossRef
  • Google Scholar
  • View reference in article

• 44

  KouS. C.PoonC. S. (2013). A novel polymer concrete made with recycled glass aggregates, fly ash and metakaolin. Constr. Build. Mater.41, 146–151. 10.1016/j.conbuildmat.2012.11.083

  • CrossRef
  • Google Scholar
  • View reference in article

• 45

  KumarR.VermaA.ShomeA.SinhaR.SinhaS.JhaP. K.et al (2021). Impacts of plastic pollution on ecosystem services, sustainable development goals, and need to focus on circular economy and policy interventions. Sustainability13 (17), 9963. 10.3390/su13179963

  • CrossRef
  • Google Scholar
  • View reference in article

• 46

  KunugiT. (1999). “High-modulus and high-strength polypropylene fibers and films,” in Polypropylene: an AZ reference (Dordrecht: Springer Netherlands), 295–300.

  • Google Scholar
  • View reference in article

• 47

  KuttimarksM. S.SinghV.VenkatamuniT.SharmaR.PandeyR. K.SudhakarM. (2025). “Building a sustainable future through innovations in green construction and recycling waste materials,” in Innovations in energy efficient construction through sustainable materials (IGI Global), 33–64.

  • Google Scholar
  • View reference in article

• 48

  LaibS.NafaZ.MerdasA.ChetbaniY.TayehB. A.TangY. (2025). Experimental and statistical evaluations of recycled waste materials and polyester fibers in enhancing asphalt concrete performance. Buildings15 (15), 2747. 10.3390/buildings15152747

  • CrossRef
  • Google Scholar
  • View reference in article

• 49

  LariaJ. G.GagginoR.KreikerJ.PeisinoL. E.PositieriM.CappellettiA. (2023). Mechanical and processing properties of recycled PET and LDPE-HDPE composite materials for building components. J. Thermoplast. Compos. Mater.36 (1), 418–431. 10.1177/0892705720939141

  • CrossRef
  • Google Scholar
  • View reference in article

• 50

  LeeH.OhsawaI.TakahashiJ. (2015). Effect of plasma surface treatment of recycled carbon fiber on carbon fiber-reinforced plastics (CFRP) interfacial properties. Appl. Surf. Sci.328, 241–246. 10.1016/j.apsusc.2014.12.012

  • CrossRef
  • Google Scholar
  • View reference in article

• 51

  LeeH. J.KimS. J.YoukJ. H.LeeK. H. (2025). Feasibility study on the production of industrial PET fibers using recycled bottle-grade PET. Fibers Polym.26 (2), 513–520. 10.1007/s12221-025-00847-x

  • CrossRef
  • Google Scholar
  • View reference in article

• 52

  LiH.YangJ.YangD.ZhangN.NazarS.WangL. (2024). Fiber-reinforced polymer waste in the construction industry: a review. Environ. Chem. Lett.22 (6), 2777–2844. 10.1007/s10311-024-01769-5

  • CrossRef
  • Google Scholar
  • View reference in article

• 53

  LiuJ.XuW.LiG.ChenB.XiaoY.HuangH.et al (2025). Performance and applications of polymer fiber rubber-reinforced concrete in civil engineering: a state-of-the-art review. Polymers17 (7), 970. 10.3390/polym17070970

  • Pubmed Abstract
  • CrossRef
  • Google Scholar
  • View reference in article

• 54

  Lopez-ManchadoM. A.ArroyoM. (2001). Optimization of composites based on PP/elastomer blends and short PET fibers. Rubber Chemistry Technology74 (2), 189–197. 10.5254/1.3544943

  • CrossRef
  • Google Scholar
  • View reference in article

• 55

  MaJ.YangQ.PengX.XiaK. (2025). Review on durability deterioration and mitigation of concrete structures. Coatings15 (9), 982. 10.3390/coatings15090982

  • CrossRef
  • Google Scholar
  • View reference in article

• 56

  MaouS.MeghezziA.GrohensY.MeftahY.KervoelenA.MagueresseA. (2021). Effect of various chemical modifications of date palm fibers (DPFs) on the thermo-physical properties of polyvinyl chloride (PVC)–high-density polyethylene (HDPE) composites. Industrial Crops Prod.171, 113974. 10.1016/j.indcrop.2021.113974

  • CrossRef
  • Google Scholar
  • View reference in article

• 57

  MarcelinoC. S.GomesV. E. D. S.Marangoni JuniorL. (2025). Post-consumer recycled PET: a comprehensive review of food and beverage packaging safety in Brazil. Polymers17 (5), 594. 10.3390/polym17050594

  • Pubmed Abstract
  • CrossRef
  • Google Scholar
  • View reference in article

• 58

  MarinelliS.ButturiM. A.RiminiB.GamberiniR.SellittoM. A. (2021). Estimating the circularity performance of an emerging industrial symbiosis network: the case of recycled plastic fibers in reinforced concrete. Sustainability13 (18), 10257. 10.3390/su131810257

  • CrossRef
  • Google Scholar
  • View reference in article

• 59

  MarkovićD.TomšičB.ZilleA.RibeiroA. I.Ilic‐TomicT.TadićV.et al (2025). Biosynthesis of silver nanoparticles on polypropylene nonwovens: towards antimicrobial protection. ChemistrySelect10 (14), e202500376. 10.1002/slct.202500376

  • CrossRef
  • Google Scholar
  • View reference in article

• 60

  MastaliM.DalvandA.SattarifardA. R.AbdollahnejadZ.IllikainenM. J. C. P. B. E. (2018). Characterization and optimization of hardened properties of self-consolidating concrete incorporating recycled steel, industrial steel, polypropylene and hybrid fibers. Compos. Part B Eng.151, 186–200. 10.1016/j.compositesb.2018.06.021

  • CrossRef
  • Google Scholar
  • View reference in article

• 61

  MeyerC. (2009). The greening of the concrete industry. Cem. Concrete Composites31 (8), 601–605. 10.1016/j.cemconcomp.2008.12.010

  • CrossRef
  • Google Scholar

• 62

  NejadB. M.EnferadiS.AndrewR. (2025). A comprehensive analysis of process-related CO2 emissions from Iran's cement industry. Clean. Environ. Syst.16, 100251. 10.1016/j.cesys.2024.100251

  • CrossRef
  • Google Scholar

• 63

  NicholsonS. R.RorrerN. A.CarpenterA. C.BeckhamG. T. (2021). Manufacturing energy and greenhouse gas emissions associated with plastics consumption. Joule5 (3), 673–686. 10.1016/j.joule.2020.12.027

  • CrossRef
  • Google Scholar

• 64

  OdehA.TahaO. S.AlmakhadmehM. N.Al-RababahA.Al-FakihA. (2025). Comprehensive review of polymer-based concrete: properties, sustainability, and challenges. Environ. Sci. Pollut. Res.32 (36), 21271–21300. 10.1007/s11356-025-36901-7

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 65

  PrzybekA. (2025). The role of natural fibers in the building industry—the perspective of sustainable development. Materials18 (16), 3803. 10.3390/ma18163803

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 66

  RashwanO.KoroneosZ.TownsendT. G.CaputoM. P.Bylone JrR. J.WodrigB.et al (2023). Extrusion and characterization of recycled polyethylene terephthalate (rPET) filaments compounded with chain extender and impact modifiers for material-extrusion additive manufacturing. Sci. Reports13 (1), 16041. 10.1038/s41598-023-41744-8

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 67

  RebeizK. S.FowlerD. W.PaulD. R. (1993). Recycling plastics in polymer concrete for construction applications. J. Materials Civil Engineering5 (2), 237–248. 10.1061/(asce)0899-1561(1993)5:2(237)

  • CrossRef
  • Google Scholar

• 68

  SasiS.JosephP.HaighR.SandanayakeM.VrceljZ.YaghoubiE. (2024). A review on the effects of waste textile polymer fiber on concrete strength: exploring the key parameters. Buildings14 (5), 1486. 10.3390/buildings14051486

  • CrossRef
  • Google Scholar

• 69

  SchultzC.CunninghamP. R.FanJ.MillerS. A. (2025). Balancing the mechanical performance and environmental sustainability of fiber-reinforced concrete. J. Mater. Civ. Eng.37 (7), 04025178. 10.1061/jmcee7.mteng-19454

  • CrossRef
  • Google Scholar

• 70

  Seifali Abbas-AbadiM.TommeB.GoshayeshiB.MynkoO.WangY.RoyS.et al (2025). Advancing textile waste recycling: challenges and opportunities across polymer and non-polymer fiber types. Polymers17 (5), 628. 10.3390/polym17050628

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 71

  ShaterM.AkbardoostJ.AsadollahfardiG.SalehiA. M.FazeliR. (2025). Effect of treated industrial wastewater and metalized plastic waste fiber on workability, mechanical properties and durability of self-compacting concrete. Constr. Build. Mater.470, 140586. 10.1016/j.conbuildmat.2025.140586

  • CrossRef
  • Google Scholar

• 72

  ShenL.WorrellE.PatelM. K. (2012). Comparing life cycle energy and GHG emissions of bio‐based PET, recycled PET, PLA, and man‐made cellulosics. Biofuels, Bioproducts Biorefining6 (6), 625–639. 10.1002/bbb.1368

  • CrossRef
  • Google Scholar

• 73

  ShenD.LiuX.ZengX.ZhaoX.JiangG. (2020). Effect of polypropylene plastic fibers length on cracking resistance of high performance concrete at early age. Constr. Build. Mater.244, 117874. 10.1016/j.conbuildmat.2019.117874

  • CrossRef
  • Google Scholar

• 74

  ShourijehP. T.RadA. M.BiglooF. H. B.BineshS. M. (2022). Application of recycled concrete aggregates for stabilization of clay reinforced with recycled tire polymer fibers and glass fibers. Constr. Build. Mater.355, 129172. 10.1016/j.conbuildmat.2022.129172

  • CrossRef
  • Google Scholar

• 75

  SiddiqueR.KhatibJ.KaurI. (2008). Use of recycled plastic in concrete: a review. Waste Management28 (10), 1835–1852. 10.1016/j.wasman.2007.09.011

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 76

  SignoriniC.VolpiniV. (2021). Mechanical performance of fiber reinforced cement composites including fully-recycled plastic fibers. Fibers9 (3), 16. 10.3390/fib9030016

  • CrossRef
  • Google Scholar

• 77

  SinghN.DemirsözR. (2022). “Recycling of traditional plastics: PP, PS, PVC, PET, HDPE, and LDPE, and their blends and composites,” in Nanomaterials in manufacturing processes (CRC Press), 235–258.

  • Google Scholar

• 78

  SoniA.KumarS.MajumderB.DamH.DuttaV.DasP. K. (2024). Synergy of waste plastics and natural fibers as sustainable composites for structural applications concerning circular economy. Environ. Sci. Pollut. Res.31 (27), 38846–38865. 10.1007/s11356-023-26365-y

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 79

  SonkeJ. E.KoenigA.SegurT.YakovenkoN. (2025). Global environmental plastic dispersal under OECD policy scenarios toward 2060. Sci. Adv.11 (16), eadu2396. 10.1126/sciadv.adu2396

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 80

  SuchorabZ.FranusM.Barnat-HunekD. (2020). Properties of fibrous concrete made with plastic optical fibers from e-waste. Materials13 (10), 2414. 10.3390/ma13102414

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 81

  SuksiripattanapongC.PhetprapaiT.SingsangW.PhetchuayC.ThumrongvutJ.TabyangW. (2022). Utilization of recycled plastic waste in fiber reinforced concrete for eco-friendly footpath and pavement applications. Sustainability14 (11), 6839. 10.3390/su14116839

  • CrossRef
  • Google Scholar

• 82

  TawiahP. O.AndohP. Y.Agyei-AgyemangA.NyarkoF. (2016). Characterization of recycled plastics for structural applications. Int. Journal Science Technology5 (6), 259–267.

  • Google Scholar

• 83

  TayS. W.ThitsartarnW.KhooH. H. (2024). “Evaluation of recycling methods: towards decarbonization of chemicals and fuels via a circular economy model,” in Towards net-zero carbon initiatives: a life cycle assessment perspective, 161–174.

  • Google Scholar

• 84

  UluA.TutarA. I.KurkluA.CakirF. (2022). Effect of excessive fiber reinforcement on mechanical properties of chopped glass fiber reinforced polymer concretes. Constr. Build. Mater.359, 129486. 10.1016/j.conbuildmat.2022.129486

  • CrossRef
  • Google Scholar

• 85

  UutelaE.BlackN. P. (1990). Recycled fiber use expected to grow by 41% and reach 130 milion tons yearly by 2001. Tappi Journal73 (7), 50–52.

  • Google Scholar

• 86

  Valverde-BurneoD.García-TroncosoN.SeguraI.García-LabordaM.SantillánN.SanchezL.et al (2025). Experimental and theoretical analysis of auxetic cementitious composite: a comparative study with recycled and virgin steel fibers. J. Build. Eng.101, 111822. 10.1016/j.jobe.2025.111822

  • CrossRef
  • Google Scholar

• 87

  VenkatachalamV.PohlerM.SpierlingS.NickelL.BarnerL.EndresH. J. (2022). Design for recycling strategies based on the life cycle assessment and end of life options of plastics in a circular economy. Macromol. Chem. Phys.223 (13), 2200046. 10.1002/macp.202200046

  • CrossRef
  • Google Scholar

• 88

  WuB.QiuJ. (2022). Enhancing the hydrophobic PP fiber/cement matrix interface by coating nano-AlOOH to the fiber surface in a facile method. Cem. Concr. Compos.125, 104297. 10.1016/j.cemconcomp.2021.104297

  • CrossRef
  • Google Scholar

• 89

  XanthopoulouE.ChrysafiI.PolychronidisP.ZamboulisA.BikiarisD. N. (2023). Evaluation of eco-friendly hemp-fiber-reinforced recycled HDPE composites. J. Compos. Sci.7 (4), 138. 10.3390/jcs7040138

  • CrossRef
  • Google Scholar