Recycled Plastic Aggregate Research Articles

USE OF PLASTICWASTE AS AN AGGREGATE IN CONCRETE

Significant growth in the consumption of plastic products is observed all over the world in recent years; this has contributed to increasing the production of plastic waste. Disposal of plastic is a challenging task. Because plastic waste can take anywhere from 20 to 500 years to decompose, and eventhen, it never fully disappears; it just get smaller and smaller. Hence it is necessary to reduce the amount of production of plastic as well as disposal and reuse of plastic is mandatory. As decomposition of plastic is a serious problem as it takes very long time and adversely affection the environment in many ways so reuse of plastic waste in the production of concrete or mortar appears as an environmentally friendly solution for getting rid of plastic waste, due to its ecological and economic advantages and we can use it in construction, where we need life of structure to be improved. Furthermore, it leads to a decrease in plastic waste in landfills. Several studies presented the properties of cementitious composites (mortar and concrete) containing different types of (PWD) Usage of these plastic waste materials helping in dual role by minimizing of concrete and by using the waste materials that are affecting the environment. The other advantage of using these waste materials is that they are helping improving the properties of concrete.This study summarizes the previous studies until 2019, discussing the use of recycled plastic aggregate as aggregates in cementation composites and its impact on the compressive strength. In this study we are going to replace the fine aggregate and coarse aggregate by plastic aggregate with 2.5%, 10% and 25%, then specimens are tested and compared with a control specimen of 0% plastic in terms of compressive strength. We will also do the comparative study of replacement of fine and coarse aggregateand going to find that which replacement is better. Keywords: plastic waste, plastic aggregate, environmentally friendly solution

Multiscale investigation of the impact of recycled plastic aggregate as a fine aggregate replacement on one-part alkali-activated mortar performance

Due to the use of solid alkaline activators, one-part alkali-activated materials, often referred to as ‘just add water' materials, have garnered increased interest for commercialization. This study primarily aimed to evaluate the impact of recycled plastic aggregate (RPA) on the performance of one-part alkali-activated mortars (OPAAM). The OPAAM samples were prepared by replacing sand with RPA, up to 50 % by volume of fine aggregate. Various properties of the OPAAM samples were examined, including flowability, density, water absorption, porosity, compressive strength, flexural strength, splitting tensile strength, and microstructural features. Experimental investigations revealed that the mechanical properties of the OPAAM decreased with an increase in RPA in the mixture. At 28 days, both the control mixture and the mixture with 10 % plastic aggregate exhibited the highest compressive strength, approximately 46 MPa, compared to the other mixtures. All mixtures consistently showed improved strength performance after 28 days. The porosity and water absorption of the samples increased with a higher replacement of fine aggregate with plastic aggregate. Microstructural findings indicated a weaker interfacial transition zone (ITZ) between the RPA-paste compared to that of the sand-paste. The ITZ appeared weakened by microcracks dispersed in the interface between the paste and recycled plastic aggregate. Despite the decrease in mechanical properties, the inclusion of RPA in amounts ranging from 10 % to 50 % resulted in significant reductions in total equivalent CO2 emissions, ranging from 22.7 % to 113.5 %. However, the benefits of using this greener option will be offset by the higher cost, ranging from 5 % to 20 %.

Innovative machine learning approaches to predict the compressive strength of recycled plastic aggregate self-compacting concrete incorporating different waste ashes

Innovative machine learning approaches to predict the compressive strength of recycled plastic aggregate self-compacting concrete incorporating different waste ashes

INVESTIGATION OF RECYCLED PLASTIC COATED WITH SAND AS A COARSE AGGREGATE IN LIGHTWEIGHT CONCRETE

Abstract— The preservation and sustainability of life on our planet are seriously threatened by environmental issues brought on by plastic pollution and excessive quarrying for natural aggregates; as a result, a workable substitute for natural aggregates would advance material sustainability. This work investigated the use of recycled plastic coated with sand as partial replacement for natural coarse aggregates in concrete production. Concrete of grade 25 was investigated in this study. Five concrete mixes involved the partial replacement of natural coarse aggregates with recycled plastic aggregate (RPA) at the ratios of 0%, 5%, 10%, 15% and 20%. Concrete samples were then subjected to Compressive strength test, Flexural strength test and Split tensile strength test according to BS EN 12390. Results indicated that the performance of plastic aggregate was optimized at 20% partial replacement of natural aggregates with crushed plastic coarse aggregates where compressive and flexural strengths were 25.4N/mm2 and 7.3 N/mm2 respectively

Machine learning-based approach for optimizing mixture proportion of recycled plastic aggregate concrete considering compressive strength, dry density, and production cost

The extensive use of plastics has resulted in significant environmental challenges due to non-biodegradable waste. Researchers explore the integration of plastic waste into construction materials, specifically as aggregates in concrete. As the inclusion of plastic aggregates can influence physical and mechanical properties of concrete, a comprehensive analysis of key concrete properties affected by plastic aggregate content should be conducted. Considering the intricate relationship between mixture proportion and properties of plastic aggregate concrete, a random forest (RF) model, a machine learning algorithm, is employed to predict compressive strength and dry density. The RF model, trained on an extensive dataset from diverse sources, demonstrates notable accuracy with low mean absolute percentage errors for compressive strength (7.2 %) and dry density (2.8 %). Moreover, the RF model provides the importance of plastic aggregate content in determining the concrete properties. Subsequently, the trained RF model is applied to optimize mixture proportions, securing compressive strengths of 20 and 30 MPa. The optimization process takes into account factors such as plastic aggregate content, production cost, dry density, and compressive strength. In comparison to experimental results from previous studies, the optimized mixtures exhibit a high strength-to-density ratio, indicating superior structural efficiency.

Performance of Metakaolin-Based Geopolymer Incorporating Recycled Plastic Aggregate

Recently, research has been devoted to producing a more sustainable and environmentally friendly composite for substituting conventional cement concrete. This supports the global effort toward limiting the environmental impact of cement production. Geopolymer composites or alkali-activated materials have gained more attention within the research community due to the wide availability of waste (e.g., fly ash, slag) or natural (metakaolin, pozzolans) source materials suitable for geopolymer production. The present study investigates the potential of producing metakaolin-based geopolymer mortars with partial substitution of natural sand by recycled plastic fine aggregate (RPFA) to enhance composite sustainability. The primary variables of the experimental program include the percentage replacement of fine natural aggregate by RPFA (0, 10, 20, and 30% by volume). Tests comprising flowability, compressive strength, Flexural strength and unit weight of the various mixes were evaluated. The results indicated that replacing 10%, 20%, and 30% of sand with RPFA caused a reduction in the compressive strength by 10.6%, 21.8%, and 33.9% relative to the control mix. The flexural strength also decreased by 17.5%, 22.4%, and 30.4% compared to the control mix. Although substituting natural aggregate with RPFA reduced the mechanical properties, it improved the mix flowability by up to 20% relative to the control mix. Additionally, a reduction in the unit weight by up to 16.2% relative to the control mix was obtained, which offer a viable mean of producing lightweight mortar.

Synergistic effects of recycled plastic aggregate and nano-silica on the elevated temperature and durability performance of self-compacting concrete

A new approach to reusing plastic waste in construction is by incorporating recycled plastic aggregates (RPA) in concrete. However, this technique negatively affects concrete properties. Previous studies have treated RPAs to mitigate this issue, but none have investigated enhancing the properties of self-compacting concrete (SCC) made with RPAs through the addition of nano-silica (NS) particles. This study aims to explore the properties of SCC with RPAs modified by NS. Sixteen mixtures were tested in three stages: evaluating the impact of NS on SCC performance, examining various RPA percentages, and using the optimal NS percentage to improve negatively affected SCC mixtures. NS particles replaced cement at 1%, 2%, and 3% in the first stage, while RPAs replaced natural fine aggregate (NFA) at fractions of 5%, 10%, 15%, 20%, 30%, and 40% in the second stage. Compressive strength was assessed over different periods and at elevated temperatures. Durability performance, including water absorption, acid attack, electrical resistivity, chloride permeability, and bulk electrical conductivity, was extensively studied. The results revealed that the addition of the optimal NS percentage effectively restored the most degraded properties of SCCs, making it a safe and effective technique for utilizing RPAs in SCC mixtures without compromising concrete performance.

RETRACTED: Fresh and mechanical performances of recycled plastic aggregate geopolymer concrete modified with Nano-silica: Experimental and computational investigation

Concerning environmental concerns, it has become crucial to invent and develop alternative construction materials that can replace ordinary Portland cement and use waste materials instead of natural aggregates in the production of concrete. An important advancement in this area is the utilization of recycled plastics to create geopolymer concrete, which helps reduce plastic waste and minimize the environmental impact of construction materials. Since plastics have become a significant environmental issue, it is imperative to find ways to recycle them for a sustainable future. Thus, this study was conducted involving the preparation of seventeen different mixtures of geopolymer concrete (GPC) in three stages. In the first stage, five GPC mixes were created with varying amounts of nano-silica (NS) ranging from 0 % to 4 %. The main objective of this stage was to determine the optimal NS content that could enhance the performance of the GPC matrix. In the second stage, recycled plastic aggregates (RPA) were introduced to replace a portion of the fine aggregates, ranging from 0.05 to 0.5 volume percentages. This aimed to assess the impact of RPAs on the fresh GPC and its mechanical properties. The third stage involved an analysis to improve the performance of the GPC compound incorporating RPAs. The optimal NS content identified in the first stage was utilized for all mixtures with RPA. Lastly, several modeling techniques, including artificial neural network, M5P tree, multiple linear regression, full quadratic, multi-expression programming, and linear regression, were employed to predict the compressive strength of the GPC compound. The results demonstrated that the addition of nano-silica increased the compressive strength of the GPC mixtures by 6.3 %, 13.4 %, 20.5 %, 21 %, and 21.9 % at curing ages of 3, 7, 28, 90, and 180 days, respectively, when using 3 % NS content compared to the control GPC mixture. However, the inclusion of NS had a negative impact on the workability of the GPC mixes. Furthermore, incorporating RPAs reduced both the workability and compressive strength of the GPC compound. In the end, the results obtained from the modeling analysis revealed that the compressive strength of GPC could be predicted with a high degree of accuracy by taking into account the mixture proportions of its constituents. Among the various techniques used, it was found that the artificial neural network model outperformed other methods in accurately forecasting the compressive strength of GPC. This indicates that the neural network model is a superior and reliable approach for estimating the strength characteristics of GPC, providing valuable insights for optimizing its composition and enhancing its overall performance.

Green lightweight concrete utilizing sustainable processed recycled plastic aggregates: Technical, economic and environmental assessment

In recent years, it has become imperative to conduct studies on the environmental effect of the construction industry on sustainability and develop strategies to mitigate sustainability risks. These mitigation strategies aim to protect natural resources and reduce waste accumulation. The life cycle analysis of buildings has been one of these studies due to the adverse environmental effects of the materials utilized in construction, particularly concrete. Specifically, how material use affects global warming and consumer desires for energy-efficient and environmentally friendly buildings. This study presents a comprehensive life cycle assessment of operational and embedded energy components that affect overall energy consumptions for concrete construction. Five concrete mixtures with varying percentages of sustainable recycled plastic aggregate were compared to a control mixtures made with normal weight and natural lightweight aggregates using a case study of a two-story residential building in Saudi Arabia. A life cycle assessment was initially used to estimate the embodied impact of producing the concrete. Then operational energy use was simulated using IES-VE. The weathering profile, transportation distance, and processing energy were all considered and calculated using site-based data for the environmental impact assessment components. The results demonstrate significant reduction of annual operational energy, carbon emissions and overall energy consumption of up to 15%, 13% and 21%, respectively. Therefore, the resulting green concrete system is more environmentally friendly due to the superior thermal performance over existing natural lightweight aggregates concrete. This evidence enables the ideas to be implemented, particularly in dry climate countries such as Saudi Arabia, where the average electricity use is very huge. Additionally, the study results suggest the possibility of permanently integrating plastic wastes into sustainable aggregate and its subsequent green concrete to reduce these wastes' adverse effects.

Microstructure characteristics, stress–strain behaviour, fresh properties, and mechanical performance of recycled plastic aggregate self-compacting concrete modified with nano-silica

Reuse of recycled plastic in the construction industry is a novel approach instead of landfilling. However, the utilization of recycled plastic aggregates (RPA) aggravated the majority of concrete properties. In previous investigations, different techniques such as surface treatment of RPAs were utilized to reduce the negative influence of the RPAs on the concrete performance. Research regarding the improvement of RPA self-compacting concrete (SCC) properties by the addition of nano-silica particles (NS) is scarce. Therefore, the current study aims to experimentally investigate the properties of the SCC-incorporated RPAs modified with NS. The experimental program contained sixteen different mixtures which were subdivided into three stages. In the first stage, the effect of NS addition on the performance of SCC mixtures was evaluated. Moreover, the effect of different percentages of RPAs was investigated in the second phase. In the third stage, the optimum percentage of NS particles found in the first stage was utilized to improve the performance of SCC mixtures which aggravated in the second stage. The total binder content for all mixtures was 500 kg/m3 which contained 70 % of cement, 20 % of ground granulated blast furnace slag (GGBFS) and 10 % silica fume. In the first stage the cement was replaced by 1 %, 2 %, and 3 % NS particles, while, in the second stage, the natural fine aggregate (NFA) was replaced by RPAs at six volume fractions (5 %, 10 %, 15 %, 20 %, 30 %, and 40 %). The fresh behaviour of all SCC mixtures was investigated to assess the flowability, filling ability, passing ability, and cohesiveness of the mixtures. The mechanical behaviour was evaluated for compressive strength, splitting tensile strength, modulus of elasticity, flexural strength, and stress–strain behaviour. Moreover, the microstructure characteristics were investigated to illustrate the modifications that occurred in the microstructure scale. The results indicated that the addition of an optimum percentage of NS particles can significantly restore most properties of RPASCC which were degraded due to the addition of RPAs. This technique can help the construction industry to safely use the RPAs in the SCC mixtures without concern about their negative impact on concrete performance.

Multi-Objective Taguchi Optimization of Cement Concrete Incorporating Recycled Mixed Plastic Fine Aggregate Using Modified Fuller’s Equation

Motivated by the multiple benefits of recycling plastic ingredients in cementitious materials, the present study focuses on the design of sustainable cement concrete incorporating recycled mixed plastic fine aggregate (MPFA) as a partial replacement of natural sand (NS). The MPFA produced in this work is composed of a combination of polymer types with similar concoctions to those observed in the postconsumer waste streams. This study approach is vastly different from past reported studies on the use of sorted, highly purified single-type recycled plastic aggregate in cement concrete. A multi-criteria decision-making technique, Best-Worst Method (BWM), was integrated with the Taguchi method to maximize the quality of MPFA concrete based on the Fuller–Thompson theory. More specifically, an L9 (34) Taguchi orthogonal array with four three-level design factors was adopted to optimize the fresh, durability, and mechanical properties of MPFA concrete. The results showed that MPFA concrete produced with 400 kg/m3 cement content, 0.43 water/cement ratio, 0.43 fine aggregate/total aggregate ratio, and 10 vol% MPFA content exhibited the highest quality. Findings from the present work also revealed that MPFA concrete produced with tailored particle size distribution of MPFA NS fine aggregate system achieved superior, if not comparable, qualities to those of conventional concrete.

THE FIRE RESISTANCE OF CONCRETE MADE WITH RECYCLED PLASTIC AS PARTIAL REPLACEMENT FOR COARSE AGGREGATE

This research is aimed to investigate the fire resistance of recycled discarded plastic when used as partial replacement for normal granite coarse aggregate in concrete when exposed to elevated temperatures. Discarded Polyethylene Terephthalate (PET) bottles were cut into a maximum size of 20mm to produce Recycled Plastic Aggregate (RPA). The replacement of normal aggregates with RPA were in proportion of 0%, 5%, 10%, 15%, 20%, 25% and 30% by weight of normal coarse aggregate. The compressive performance of the concrete made with RPA were studied by casting three 100 mm cubes for each of the percentage replacements and tested at 7, 14 and 28 days of curing age. A set of three (3) concrete cubes for each percentage replacement was cured for 28 days and subjected to a temperature of 718oC for a duration of 15 minutes in a furnace. Results of slump tests on fresh concrete showed that workability decreased with increase in RPA. Densities and compressive strengths for normal cube samples not subjected to elevated temperatures and the sample subjected to temperature of 718oC increased with increase in curing age and decreased with increase in percentage of RPA. The result showed that the concrete specimen with 10% replacement of RPA was optimum for good thermal stability.

Durability of recycled waste plastic aggregate concrete

The durability of waste plastic aggregate (WPA) concrete was investigated. Concrete specimens prepared with varying proportions and shapes of WPA were prepared and their durability was evaluated. The bond between WPA and cement mortar was evaluated using scanning electron microscopy. The water absorption of WPA concrete was more than that of normal concrete. The water absorption of fibre-, flake- and granule-type WPA concrete was 16–28%, 15–35% and 14–32% more than that of control concrete, respectively. The chloride permeability (CP) of WPA concrete decreased; however, it was almost in a similar range (2200–3550 Coulombs) in all the specimens. Corrosion initiation was delayed in WPA concrete, except in the fibre-type WPA. The corrosion rate (CR) decreased by 34–82% in granule-, 23–60% in flake- and 11–20% in fibre-type WPA concrete compared to the control concrete. The compressive strength of concrete exposed to heat/cool cycles for 3 months decreased by 2–19% as the quantity of WPA increased indicating debonding between WPA and the cement mortar due to thermal variations. Due to its improved durability, concrete with up to 50% WPA can be used in construction of structures with low to moderate durability requirements.

Impact of recycled plastic aggregate concrete in high-temperature environments

Impact of recycled plastic aggregate concrete in high-temperature environments

Utilization of recycled PET plastic waste as replacement of coarse aggregate in pervious concrete

This study aimed to determine the effects of using plastic waste as a natural coarse aggregate replacement in pervious concrete with different sizes of coarse aggregate. The plastic waste used in this experiment was of the Polyethylene Perephtalate (PET) type obtained from the mineral water bottles. The plastic waste was formed to be similar to the natural coarse aggregate sizes of 5–10 mm and 10–20 mm, replacing 5% of the coarse aggregate in pervious concrete. In order to obtain the appropriate proportions, three ratios of aggregate: cement (2:1, 3:1, and 4:1) were used in the preliminary experimental stage. The aggregate: cement ratio of 3:1 was then evaluated by including the addition of the recycled PET plastic aggregate in the compressive strength and void ratio tests. Based on the results, it was found that the pervious concrete containing 5% of recycled plastic aggregate improved on the 7th day in terms of compressive strength. However, on the 28th day, the compressive strength was observed to be comparable with the pervious concrete. The void ratio test showed that the use of plastic waste can increase the percentage of connected voids compared to the pervious concrete control. Furthermore, the use of recycled PET plastic waste, when properly proportioned and treated, can be used in pavement areas and other forms of construction where there are light loads.

Performance Evaluation of Plastic Concrete Modified with E-Waste Plastic as a Partial Replacement of Coarse Aggregate.

Plastic electronic waste (E-waste) is constantly growing around the world owing to the rapid increase in industrialization, urbanization, and population. The current annual production rate of E-waste is 3–4% in the world and is expected to increase to 55 million tons per year by 2025. To reduce the detrimental impact on the environment and save natural resources, one of the best solutions is to incorporate waste plastic in the construction industry to produce green concrete. This study examines the use of manufactured plastic coarse aggregate (PCA) obtained from E-waste as a partial replacement of natural coarse aggregate (NCA) in concrete. Six types of concrete mix with 10%, 20%, 30%, 40%, and 50% substitution of NCA (by volume) with PCA are prepared and tested. This study investigates the effect of manufactured PCA on the fresh and hardened characteristics of concrete. The properties of recycled plastic aggregate concrete (RPAC) studied include workability, fresh density, dry density, compressive strength (CS), splitting tensile strength (STS), flexural strength (FS), sorptivity coefficient, abrasion resistance, ultrasonic pulse velocity (UPV), and alternate wetting and drying (W–D). The results indicate that the CS, STS, and FS of RPAC declined in the range of 9.9–52.7%, 7.8–47.5%, and 11–39.4%, respectively, for substitution ratios of 10–50%. However, the results also indicate that the incorporation of PCA (10–50%) improved the workability and durability characteristics of concrete. A significant decrement in the sorptivity coefficient, abrasion loss, and UPV value was observed with an increasing amount of PCA. Furthermore, RPAC containing different percentages of PCA revealed better results against alternate W–D cycles with respect to ordinary concrete.

STABILIZATION OF LEACHATE IN AGGREGATES MADE WITH PLASTIC FROM WEEE

A recycled plastic aggregate (RPA) was developed using the core-shell strategy, where the core is the plastic fraction of Waste of Electrical and Electronic Equipment (WEEE) and a cement matrix with stabilizing additives acts as the shell. The amount of brominated flame retardant (mainly tetrabromobisphenol-A) leached in curing water of RPAs was quantified using extraction with an organic solvent and gas chromatography methods (CG-FID). A clear relationship can be established between the characteristics of the stabilizing additive used and the amount of tetrabromobisphenol-A and bisphenol-A leached. The additive used was activated carbon, which in a manufacture scale may be provided by different suppliers with different mesoporous characteristics, which can be easily determined by the iodine number. The analysis proposed can be an effective way to determine if a particular activated carbon can be used as stabilizing additive in the production of RPAs with the developed technology.

Microwave radiation treatment to improve the strength of recycled plastic aggregate concrete

In this study, microwave radiation pre-treatment (MRP) of three recycled plastic aggregates, namely; Polyethylene Terephthalate (PET), High-Density Polyethylene (HDPE) and Polypropylene (PP), was carried out to enhance the bond strength between the plastic aggregates and the concrete matrix. Five concrete mixes were prepared, which included treated and untreated PET plastic aggregate, treated and untreated mixed plastic type aggregates and a control mix without any plastic. The replacement was 15% by volume as a partial replacement of coarse aggregate for all mixes. The modification of plastic surface was assessed before and after the microwave treatment by measuring the contact angle of a water droplet and using SEM images. The engineering characterizations of the concrete incorporating microwave treated recycled plastic aggregates were assessed through investigating physical and mechanical properties as well as water absorption. The results demonstrated that the Interfacial Transition Zone (ITZ) was improved due to PET plastic surface treatment, leading to an improvement in the strength of concrete. No improvement was seen in the strength of concrete that included treated mixed plastic types. Scanning electron microscopy (SEM) images of the treated plastic surface illustrated more roughness in the treated PET plastic surface, while the images of ITZ showed an improvement in the adhesion between the plastic and the cement paste. Despite the unexpected results of the treated mixed recycled plastic, the positive strength results of the concrete containing treated PET indicated that there is a potential for microwave treatment to be used as a method to induce surface modification.

Mechanical Properties of Lightweight Concrete Made with Shredded Waste Polypropylene Yogurt Containers

The partial replacement of natural coarse (gravel) aggregate by waste plastic aggregate to produce lightweight concrete has become one of the major challenges in recent years and stresses on the need for a constant and authoritative development for the betterment of the environment. This work was carried out to investigation the possibilities of using waste polypropylene yogurt containers as polymer aggregate in concrete application. The concrete samples with 0%, 5%, 10%, 15%, 20% and 25% recycled waste plastic aggregate as partial replacement by mass of natural coarse aggregate are prepared after a curing period of 28 days. The effect of recycled plastic aggregate on compressive strength, density and water absorption of natural concrete are studied and compared with the results of specimen without plastic aggregate. Both compressive strength and density decreased with increasing the amount of plastic aggregate. The highest reduction in compressive strength and density were 50% and 19% respectively of concrete cubes containing 25% wt polypropylene waste aggregate in comparison of traditional concrete. It was found that water absorption increased as the plastic aggregate content increased up to 15% wt and then decreased when replaced coarse aggregate by 20% wt and 25% wt by recycled polypropylene aggregate. This study is recommended to use recycled polypropylene yogurt containers as a partial substance of traditional coarse (gravel) concrete mix up to 15% wt for applications include those where low compressive strengths and low cost production are desirable.

Mechanical Properties of Cement-Based Materials with Recycled Plastic: A Review

This study summarizes existing studies on plastic recycling to determine whether ocean plastics with high pollution degrees could be used for cement-based materials. In particular, the methods to recycle plastic waste, the effects of recycled plastic on the physical and mechanical properties of cement-based materials, and their effective usage were investigated. Workability, density, compressive strength, split tensile strength, and flexural strength of cement-based materials with recycled plastics were reviewed and divided into recycled aggregates and fibers. Based on the previous investigation, the direction of research necessary to recycle marine plastics is suggested. As the amount of recycled plastic aggregate increased, the mechanical strength of cement-based materials decreased. The recycled plastic aggregate lowered the density and increased porosity of the cement-based material. Meanwhile, recycled plastic fibers reduced the compressive strength but improved the tensile strength; to effectively improve tensile strength, a volume content of less than 1.5% should be added to prevent balling fibers. Furthermore, an appropriate aspect ratio should be determined based on the type of plastic to be used.