Search Results (41)

The growing disposal of used tyres and plastic waste in landfills poses a significant environmental challenge. This study investigates the potential of utilizing used tyre rubber and macro-synthetic fibres (MSFs) made from recycled plastics in fibre-reinforced rubberized concrete (RuFRC). Various percentages of tyre rubber shreds were used to replace coarse aggregates, calculated as 10%, 20%, and 30% of the volume of fine aggregates; fibre dosages (0%, 0.25%, 0.5%, 0.75%, and 1% by volume) were incorporated into the mix, and a series of physical, mechanical, and durability properties were evaluated. The results show that, as the fibre and rubber content increased, the slump of RuFRC decreased, with the lowest value obtained for concrete with 1% fibre and 30% rubber. The density of RuFRC decreases as the rubber percentage increases due to air voids and increased porosity caused by the rubber. The strength properties of RuFRC were found to decline with the increase in the rubber content, with mixes containing 30% rubber exhibiting reductions of about 60% in compressive strength, 27% in tensile strength, and 13% in flexural strength compared to the control specimen. Durability testing revealed that an increased rubber content led to higher water absorption, water penetration, and chloride ion permeability, with 30% rubber showing the highest values. However, lower rubber content (10%) and higher fibre dosages improved the durability characteristics, with water absorption reduced by up to 5% and shrinkage strains lowered by about 7%, indicating better compaction and bonding. These results indicate that RuFRC with moderate rubber and higher fibre content offers a promising balance between sustainability and performance. Full article

Recycling plastics waste into concrete represents one of the possible approaches for its valorization, offering both economic and environmental benefits. Although numerous studies have explored the mechanical properties of concrete with plastics waste, its durability performance remains largely unexplored. In this context, this study aims to assess the electrochemical behavior of rebars embedded in reinforced concrete modified by partially replacing natural aggregates with recycled plastics, comparing their behavior to that of conventional concrete. The corrosion of reinforcing steel bars was evaluated by wet and dry cycles (w/d) in calcium chloride solutions, monitoring corrosion potential and potentiostatic polarization resistance, and recording electrochemical impedance spectroscopy (EIS) and polarization curves. In addition, the chloride diffusion tendency and the mechanical performances were assessed in unreinforced samples. The findings indicate that in environments with lower chloride concentrations, concrete with plastic granules provides good protection against rebar corrosion. Although the mechanical results of the studied mixes confirmed that incorporating plastic granules as aggregates in the concrete matrix causes a reduction in compressive strength, as known in the literature, the modified concrete also exhibits improved post-cracking behavior, resulting in enhanced ductility and fracture toughness. Full article

This study underscores the importance of sustainable practices by exploring the utilization of recycled plastic within the global construction industry. Plastic recycling has emerged as a crucial strategy that aligns with environmental, social, and economic sustainability indicators. Currently, substantial volumes of plastic waste are either deposited in landfills or incinerated, neglecting the potential to harness its embodied energy and the energy consumed for producing virgin materials. A key advantage of plastic lies in its promising mechanical properties. Concrete mix design is fundamental to a wide range of construction applications, including brick walls, reinforced concrete slabs, and concrete pavements. Despite the adoption of recycled plastic in construction materials in various countries, its widespread implementation remains limited. This is primarily due to the scarcity of experimental research in this area and the absence of a robust waste management system. This research specifically investigates the reuse of two common types of plastic waste: polyethylene terephthalate (PET) and high-density polyethylene (HDPE) to mitigate plastic waste accumulation in landfills and enhance the performance of construction materials. The study investigates the use of recycled HDPE and PET as a replacement for coarse aggregates in concrete pavement mixtures. While recycled PET is more prevalent in concrete applications, recycled HDPE has demonstrated exceptional efficiency and durability. The recycling method used in this research is the mechanical recycling method due to its superior effectiveness in comparison with other methodologies. This research assesses the performance of recycled PET and HDPE in concrete pavement, aiming to diminish non-renewable energy consumption by 15–20%, curtail the carbon footprint by 15–30%, and decrease plastic waste in landfills by 20–30% compared to conventional concrete. Full article

Plastic waste management remains a significant global challenge, with limited recycling opportunities contributing to its status as one of the highest waste producers. In Australia, the recovery rate for plastic waste is 12.5%, resulting in a high percentage of plastics being landfilled. Common disposal methods, such as incineration and landfilling, are environmentally damaging, with incineration emitting harmful gases and landfilling causing contamination. Recycling, while preferable, faces difficulties due to contamination and infrastructure challenges. However, alternative solutions, such as integrating waste plastic into concrete, present an opportunity to both reduce plastic waste and enhance the economic value of recycled materials. This study evaluates the potential of waste plastic milk bottles (PMBs) in residential concrete by assessing their mechanical strength, environmental impact, and variability in greenhouse gas (GHG) emissions. This study demonstrated that replacing up to 10% of cement with silica fume-modified plastic milk bottle (SFPMB) waste granules maintained comparable compressive strength to traditional concrete. The addition of metakaolin to the SFPMB mix design (SFMKPMB) further improved the material’s strength by 28%. Life cycle assessment (LCA) results revealed reductions in global warming potential (GWP), human toxicity potential (HTP), and fossil depletion potential (FDP), with SFMKPMB showing the greatest environmental savings. A Monte Carlo simulation evaluated variability factors, revealing that additional transportation and energy requirements increased GHG emissions, though the SFMKPMB mix ultimately resulted in the lowest overall material GHG emissions. This study demonstrates the complexity of assessing “green” materials and highlights how material variability and energy use can influence the sustainability of waste-derived composites. Despite challenges, incorporating waste plastics into concrete offers a promising strategy for mitigating landfill waste and reducing environmental impacts, especially as renewable energy adoption increases. Full article

This study explores the integration of recycled polypropylene (PP) plastic (PL) pellets into concrete mixtures, to evaluate their impact on compressive strength, workability, and weight reduction. Concrete samples were prepared by replacing conventional aggregates with PL pellets at varying percentages (1%, 3%, and 5%) by weight. The primary objective was to determine the optimal PL content that enhanced the properties of concrete. The experimental results demonstrated that incorporating 3% PP-PL pellets led to an 11.3% increase in compressive strength compared with the reference mix (0% PL). Furthermore, the 3% PL mix maintained a slump value comparable to that of the reference mix, indicating that this level of PL inclusion did not negatively affect workability. However, increasing the PL content beyond 3% resulted in a significant reduction in workability, suggesting that excessive PL may limit practical applications. The inclusion of PL pellets also contributed to a decrease in the overall weight of the concrete, showcasing the potential for producing lightweight, high-performance concrete. These findings highlight the feasibility of utilizing recycled PL in concrete production as a sustainable strategy to enhance material properties while addressing the growing issue of PL waste. This study identified 3% PL as the optimal dosage for achieving the best balance between strength, workability, and weight reduction. This research contributes to the development of more sustainable construction materials while also offering insights into the role of recycled PL in improving concrete performance. Future research could focus on evaluating the long-term durability, microstructural behavior, and environmental impact of PL-modified concrete to better understand its potential for broader application in eco-friendly infrastructure, ensuring it meets the demands of sustainable and cost-effective construction practices. In addition, this study’s findings pave the way for future investigations into optimizing other types of recycled PL for use in concrete. Full article

In Mexico, approximately 6.5 million tons of plastic waste is generated, of which 38–58% is improperly managed and has the potential to leak into the environment. Furthermore, producing natural aggregates is associated with the unsustainable use of non-renewable resources. In this sense, this work aimed to evaluate the influence that recycled aggregates from plastic waste have on the behavior of concrete. Coarse aggregates of thermoplastic paint (TP) from paving waste were prepared and incorporated into four mixes, with concentrations of 5 to 20%. In addition, three mixes with fine aggregates from PET were evaluated as one reference mix. The studied properties were slump, compressive strength, flexural strength, rebound number, density, absorption, and porosity. The results indicate that both aggregates have significant potential for use in concrete, including structural use, when replacement percentages of around 5% are considered, with property losses not exceeding 8%. Their use is proposed for active mobility infrastructure, with percentages of up to 20% analyzed in this study. Finally, it is necessary to analyze the influence that the incorporation of plastic waste has on mitigating environmental impacts, as well as the durability properties. Full article

The construction field is one of the largest sectors and industries worldwide. This industry is the main industry accused of contributing to greenhouse gases and increasing the effects of climate change. However, the construction industry is indispensable, accordingly in an attempt to decrease the greenhouse gas effects of construction this research presents the manuscript for building a one-story building with all components including waste products. The building model used a strip foundation with a concrete mix design incorporating recycled concrete as a partial replacement for aggregates, cement hollow blocks containing granite waste instead of conventional cement blocks, and sandwiched insulated panels made of wood-plastic composites for the roof. The structural soundness of the system was tested by loading it with a load surpassing its design load in addition to measuring the deflection and checking its abidance to the code limitations. The thermal efficiency was tested by measuring the temperatures in comparison with the outside of the building for a span of 7 days with data recorded every 1 h. Analysis of both the short-term and long-term costs and carbon emissions was performed by acquiring the carbon emissions per unit of material from literature and multiplying it by the quantities of the materials used within the different building alternatives. That study showed that the roofs made of Structural Insulated Panels (SIPs) using Wood-Plastic Composite (WPC) facings when used with hollow-block cement block walls have shown enduring cost efficiency and improved thermal insulation, leading to diminished energy usage, life-cycle expenses, and carbon emissions. Furthermore, the proposed system is more environmentally friendly than conventional reinforced concrete technologies due to their lower costs and emissions in addition to improving sustainability through utilizing recycled materials. Full article

The glass fiber-reinforced polymer (GFRP) materials of wind turbine blades can be recovered and recycled by crushing, thereby solving one of the most perplexing problems facing the wind energy sector. This process yields selectively crushed wind turbine blade (SCWTB), a novel waste that is almost exclusively composed of GFRP composite fibers that can be revalued in terms of their use as a raw material in concrete production. In this research, the fresh and mechanical performance of concrete made with 1.5%, 3.0%, 4.5%, and 6.0% SCWTB is studied. Once incorporated into concrete mixes, SCWTB waste slightly reduced slumps due to the large specific surface area of the fibers, and the stitching effect of the fibers on mechanical behavior was generally adequate, as scanning electron microscopy demonstrated good fiber adhesion within the cementitious matrix. Thus, despite the increase in the content of water and plasticizers when adding this waste to preserve workability, the compressive strength only decreased in the long term with the addition of 6.0% SCWTB, a value of 45 MPa always being reached at 28 days; Poisson’s coefficient remained constant from 3.0% SCWTB; splitting tensile strength was maintained at around 4.7 MPa up to additions of 3.0% SCWTB; and the flexural strength of mixes containing 6.0% and 1.5% SCWTB was statistically equal, with a value near 6.1 MPa. Furthermore, all mechanical properties of the concrete except for flexural strength were improved with additions of SCWTB compared to raw crushed wind turbine blade, which apart from GFRP composite fibers contains approximately spherical polymer and balsa wood particles. Flexural strength was conditioned by the proportion of fibers, their dimensions, and their strength, which were almost identical for both waste types. SCWTB would be preferable for applications in which compression stresses predominate. Full article

Recycling solid waste is one of the most important ways to reduce carbon footprints and put sustainability into practice. This research aims to bridge the gap between the results of previous studies and the effectiveness and sustainability benefits of using plastic waste (PW) in concrete mixes by partially replacing coarse aggregate with PW. Furthermore, we examine the suitability of the concrete produced for use as a construction material. The research methodology is based on studying the physical and mechanical behavior of concrete produced by partially replacing coarse aggregate with 0%, 2.5%, 5%, 7.5%, 10%, and 12.5% PW. For the conventional concrete–CC mix of 0% PW, the design strength, f_cu, was 35 MP, with a slump of 100 mm, using a water–cement ratio of 0.5, a M.A.S of coarse aggregate of 20 mm, and a sand F.M. of 2.2. According to British standards, BS, slump and density tests were carried out for concrete samples produced in their fresh state and strength tests, ultrasonic testing, etc. for concrete samples after hardening. The results indicated that there is no significant difference between the dry density and bulk density of concrete produced at all its age stages, regardless of the percentage of PW that replaces the aggregate. It also indicated that the compressive strength, the flexural strength, and the splitting tensile strength of the produced concrete decrease steadily and significantly when aggregates are replaced by PW by more than 2.5%. It was found that the decrease in compressive strength does not exceed 1% for concrete with 2.5% PW compared to the strength of CC, while the compressive strength of concrete with 5% PW decreases by 24%. The maximum reduction rate of the flexural strength and splitting tensile strength was 40% and 32%, respectively, for concrete at 12.5% PW compared to the strength of CC. Therefore, PW concrete can retain its strength when used in small quantities of up to 2.5% and can be applied in structural works. Full article

Plastics are essential in modern civilization due to their affordability, simple manufacturing, and properties. However, plastics impact the environment as they decompose over a long period and degrade into microplastics. The construction sector has been exploring substituting conventional bricks with plastic bricks, as concrete and clay bricks consume natural resources and pollute the environment. The introduction of recycling plastic, and using plastic waste and sand mixtures to create Lego-like bricks has become a new trend. The bricks have superior properties to conventional bricks, such as a smoother surface, finer edges, easy application, crack-free, higher compression strength, almost zero water absorption, and reduced energy consumption. The study: compares the results of PE with sand and PET with sand samples to previous studies, confirms alignment, works as a control sample for PET and PE novel research, and validates the concept. Three plastic mixtures using two types of plastic waste (PE and PET) and sand were used. The plastic waste with sand was heated up to 200 °C. Plastic acts as a binder, while sand acts as a filler material. Optimized durability and cohesiveness were achieved at 30–40% plastic weight ratios. A mixture of PE and sand showed a maximum compressive strength of 38.65 MPa, while the PET and sand mixture showed 76.85 MPa, and the mix of PE and PET in equal proportions with sand resulted in 26.64 MPa. The plastic samples showed ductile behavior, with elongation between 20 and 30%, water absorption between 0 and 0.35%, and thermal conductivity from 0.8 to 1.05 W/(m/K). Carbon dioxide emissions are significantly reduced as compared to standard bricks. The CO₂ per brick (kg) was 0.008 and 0.0085 in the PE; 0.0085 and 0.009 in the PET; and 0.0065 and 0.007 in the PE mixed with PET. Full article

Solid waste management is a major environmental challenge, especially in developing countries, with increasing amounts of waste glass (WG) and waste plastic (WP) not being recycled. In Ethiopia, managing WG and WP requires innovative recycling techniques. This study examines concrete properties with WG and WP as partial replacements for fine aggregate. Tests were conducted on cement setting time, workability, compressive strength, splitting tensile strength, and flexural strength. Concrete of grade C-25, with a target compressive strength of 25 MPa, was prepared by partially replacing fine aggregate with WP and WG. The mechanical properties were evaluated after 7 and 28 days of curing. At a 20% replacement level, workability decreased at water–cement ratios of 0.5 and 0.6 but remained stable at 0.4, leading to the selection of the 0.4 ratio for further testing. A 10% replacement of fine aggregate, using a ratio of 3% WP and 7% WG, was found to be optimal, resulting in an increase in compressive strength by 12.55% and 6.44% at 7 and 28 days, respectively. In contrast, a 20% replacement led to a decrease in compressive strength by 14.35% and 0.73% at 7 and 28 days, respectively. On the 28th day, the splitting tensile strength at the optimal replacement level was 4.3 MPa, reflecting an 8.5% reduction compared to the control mix. However, flexural strength improved significantly by 19.7%, from 12.46 MPa to 15.52 MPa. Overall, the incorporation of WG and WP in concrete enhances flexural strength but slightly reduces splitting tensile strength. Full article

To solve the problems on resource utilization and environmental pollution of waste concrete and waste polypropylene (PP) plastics, the recycling of them into asphalt pavement is a feasible approach. Considering the high melting temperature of waste PP, this study adopted a thermal-and-mechanochemical method to convert waste PP into high-performance warm-mix asphalt modifiers (PPMs) through the hybrid use of dicumyl peroxide (DCP), maleic anhydride (MAH), and epoxidized soybean oil (ESO) for preparing an asphalt mixture (RCAAM) containing recycled concrete aggregate (RCA). For the prepared RCAAM containing PPMs, the mixing temperature was about 30 °C lower than that of the hot-mix RCAAM containing untreated PP. Further, the high-temperature property, low-temperature crack resistance, moisture-induced damage resistance, and fatigue resistance of the RCAAM were characterized. The results indicated that the maximum flexural strain of the RCAAM increased by 7.8~21.4% after using PPMs, while the sectional fractures of the asphalt binder were reduced after damaging at low temperature. The use of ESO in PPMs can promote the cohesion enhancement of the asphalt binder and also improve the high-temperature deformation resistance and fatigue performance of the RCAAM. Notably, the warm-mix epoxidized PPMA mixture worked better close to the hot-mix untreated PPMA mixture, even after the mixing temperature was reduced by 30 °C. Full article

This study investigates the feasibility of utilizing recycled plastic waste as a partial substitute for sand in concrete production. Reprocessing used plastic items or materials involves collecting, cleaning, shredding, and melting, resulting in reprocessed plastic particles. Incorporating these recycled plastic particles into concrete addresses environmental concerns related to plastic disposal and the growing scarcity and increasing cost of natural sand. To evaluate the sand replacement capacity of recycled plastic, four types of mixtures were created with varying levels of recycled plastic replacement (5%, 10%, 15%, and 20%). All mixtures maintained a water-to-binding ratio of 0.55 and were tested at 7, 28, and 56 days. The testing regimen encompassed determining the slump value, density, compressive strength, tensile strength, and resistance to freezing and thawing. The findings revealed that replacing sand in the concrete mix with recycled plastic enhanced workability, which was attributed to the hydrophobic nature of the plastic particles. However, both compressive and tensile strength exhibited a declining trend. Additionally, after undergoing multiple freezing and thawing cycles, the concrete mix exhibited poor durability properties and brittleness. These issues may arise due to factors such as incompatibility, non-uniformity, reduced cohesion, and the lower density of plastic particles. Full article

This research takes on a scientific problem originating from the pervasive deterioration observed in the pavements of Bus Rapid Transit (BRT) systems, which presents formidable challenges to their durability and imposes significant financial burdens on BRT organizations. While wear and tear on BRT pavements is a widely recognized concern, there exists a pronounced deficiency in sustainable solutions to address this issue comprehensively. This study endeavored to bridge this scientific gap by exploring the option of incorporating waste plastic aggregate (WPA) and recycled asphalt pavement (RAP) into the pavement material. The series of comprehensive investigations commenced with an assessment of modified binders. We identified a 25% extracted RAP binder as the most suitable candidate. Our research next determined that a 4% WPA content offers optimal results when used as an aggregate replacement in a stone-modified asphalt concrete mix, which is further refined with a 13 mm nominal maximum aggregate size (NMAS) gradation, resulting in superior performance. Under double-load conditions of the Hamburg Wheel Tracking test, rutting in the 10 mm NMAS mixture rapidly increased to 9 mm after 12,400 HWT cycles, while the 13 mm NMAS mixture showed a more gradual ascent to the same critical rutting level after 20,000 HWT cycles (a 61% increase). Real-world application at a designated BRT station area in Seoul reinforced the findings, revealing that the use of 13 mm NMAS with 4% WPA and RAP significantly improved performance, reducing rutting to 75 µm and enhancing pavement resilience. This configuration increased Road Bearing Capacity (RBC) to 5400 MPa at the center zone, showcasing superior load-bearing capability. Conversely, the 10 mm NMAS mixture without RAP and WPA experienced severe rutting (220 µm) and a 76% reduction in RBC to 1300 MPa, indicating diminished pavement durability. In general, this research highlights the need for innovative solutions to address BRT pavement maintenance challenges and offers a novel, environmentally friendly, and high-performance alternative to traditional methods. Full article

India is confronted with the substantial issue of plastic debris due to the absence of an efficient waste management infrastructure. Recycled plastic has the potential to enhance various construction materials, such as roofing tiles, paving blocks, and insulation. The aforementioned materials possess notable attributes such as high strength, low weight, and exceptional resistance to extreme temperatures and humidity. The objective of this study is to ascertain feasible alternatives for manufacturing road paver blocks utilizing plastic waste (Polyethene terephthalate (PET)), and M-sand (stone dust). Three variations of a discarded plastic cube measuring 150 mm × 150 mm × 150 mm were prepared for the experiment. The experimental findings indicated that a ratio of 1:4 was determined to be the most effective in achieving the desired level of compressive strength. I-section road and brick paver blocks were produced as an alternative to the traditional concrete ones. Compressive strength tests were performed on I-sections and brick paver blocks, revealing that the 1:4 mix ratio exhibited the highest average compressive strength for both materials. The findings indicated that including plastic waste positively impacted the compressive strength of the I-sections and brick paver blocks. Additionally, the quality grading of these materials was evaluated using an ultrasonic pulse velocity test. The ultrasonic pulse velocity test results demonstrated a high-quality grading for the I-sections and brick paver blocks. Scanning electron microscopy (SEM) tests assessed the microstructural behavior and performance. The results of this study demonstrate that incorporating plastic waste in combination with M-sand can effectively improve the mechanical characteristics of composite materials, rendering them viable for use in construction-related purposes. Full article