Recycling Of Waste Tires Research Articles

Miscibility, thermal, and mechanical properties of recycled waste tire rubber-modified polystyrene sustainable composites

Waste tires represent an important source of polymer waste. The ground tire rubber derived from waste tires is a recycled product that can be combined with polystyrene (PS) to produce high-performance PS and waste rubber composites. To improve composite material performance, surface grafting modification of waste tire rubber with styrene to enhance properties of PS composites as a novel approach was investigated. The surface morphology and structure of polystyrene grafted waste tire rubber powder via a conventional free radical polymerization were confirmed successfully using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy analyses in addition to the Fourier-transform infrared spectroscopy (FTIR). The comparative mechanical and thermal property analysis of PS sustainable composites with recycling waste tire rubber powder with and without surface grafting modifications indicated an approximate 4-fold increase in the impact strength of polystyrene grafted waste tire rubber reinforced PS sustainable composites in addition to enhanced interfacial miscibility. The development of sustainable composite materials from recycled waste tire provides a novel avenue to achieve close-loop polymer recycling, which is of significance in the development of the circular economy and an environmentally friendly society.

Аналіз потенціалу отримання композиційного моторного палива з відходів пластику та поліетилену та відходів зношених шин в Україні

This study analyses the volumes of plastic, polyethylene, and waste tires generated in Ukraine and assesses the potential for obtaining alternative fuels from these wastes. This waste is accumulating rapidly around the world, and Ukraine is no exception. Therefore, the purpose of this study is to determine the potential for obtaining domestic alternative fuels from waste plastic, polyethylene, and waste tires. The subject of study is the encompasses waste plastic, polyethylene, and waste tires. The subject of the study is waste plastic, polyethylene, and worn-out tires, and their energy potential for alternative fuel production. The working hypothesis of the study is that the establishment of an environmentally friendly collection and processing of these wastes can partially resolve the energy situation in the country. A systematic review of existing studies was chosen as the research method, as official data from the State Statistics Service of Ukraine does not fully reflect the current state of waste generation. The study revealed the following. The volume of plastic waste generated in Ukraine annually ranges from 990 thousand tonnes/year to 1820 thousand tonnes/year, with an average of 1405 thousand tonnes/year. Accordingly, the amount of fuel that can be obtained from plastic waste ranges from 297 thousand tonnes/year to 1729 thousand tonnes/year. Every year, 3–4.1 million tonnes of polyethylene waste remains unrecycled. The potential for producing fuel from polyethylene waste ranges from 1500 thousand tonnes per year to 3700 thousand tonnes per year. Ukraine generates 225–360 thousand tonnes of unused worn-out tires annually. The potential for obtaining fuel from waste tires ranges from 67.5 thousand tonnes per year to 180 thousand tonnes per year. Thus, the total potential for obtaining motor fuel from waste plastic, polyethylene, and waste tires ranges from 1864.5 thousand tonnes/year to 5609 thousand tonnes/year and indicates the need to establish environmental management of these wastes in Ukraine. The proposed hypothesis has been substantiated by the results of these studies. Keywords: composite motor fuels, plastic recycling, polyethylene recycling, waste tire recycling, environmental protection, energy efficiency, decarbonization.

Enhanced tire oil production through hydrothermal liquefaction using devulcanization agents

The waste refinery concept has emerged as a solution to manage waste tires and motor oil, which pose significant environmental challenges. In this study, we compared two hydrothermal liquefaction (HTL) processes. The first is a conventional method using only water as a devulcanization agent (H0 process), while the second is a novel method using a mixture of devulcanization agents (H1 process: waste engine oil, water, hydrogen peroxide, benzoyl peroxide, and potassium persulfate). We investigated the effects of temperature, residence time, and water ratio (water/tire) on the yield of these HTL processes. The highest tire crude oil yield (73.4 %) was obtained at 375°C, 7.5 water ratio, and 40 min residence time, in the H1 process. These findings suggest a promising approach for more efficient and environmentally friendly waste tire recycling. Comparison between H0 and H1 yields demonstrated significant improvements with the implementation of devulcanization agents. The H1 process reduced the optimum process temperature by 47°C, increased tire crude oil yield by 41 %, reduced tire char yield by 35 %, and improved energy recovery by 26.32 % under optimum conditions. Compared to H0 tire crude oil, H1 tire crude oil showed reduced levels of all elements except hydrogen, and was notably sulfur-free, while H0 tire crude oil contained significant amounts of sulfur. GC-MS results indicated that these improvements are attributed to enhanced hydrogenation and desulfurization reactions in the H1 process.

Upgrading pyrolysis carbon black by recyclable ferrate/alkaline treatment with the assistance of ultrasound

The recycling of pyrolysis carbon black (CBp) from waste tires is crucial in consideration of the conservation of secondary resources and the alleviation of potential hazardous effects on the environment. However, the high ash content, low surface activity and big particle size limit its high-value utilization, such as the reinforcing of tires. In this work, a novel approach of upgrading CBp derived from waste tires has been developed by a combination of recyclable ferrate/alkaline treatment and ultrasound. In this approach, the ferrate/alkaline is used to remove impurities of CBp and introduce oxygen groups with high activities, and the ultrasound can break the agglutinated CBp particles and accelerate the impurities reduction effectively. Upgrading conditions including temperature, reaction time, and reagent ratio were explored and optimized. Compared with non-upgraded CBp (n-CBp), the upgraded CBp (u-CBp) had a much lower content of impurities (1.74%) and a comprehensive promotion in physicochemical properties. The u-CBp exhibited superior in-rubber performance to the commercial carbon black (N550/N660). Furthermore, the ferrate can be recycled to upgrade CBp several times. This method offered a promising solution of CBp upgrading and waste tire recycling and contribute to the closed-loop recycling of waste tires and environmental sustainability.

Prospects of electricity generation through the use of alternative sources such as waste tires processing products

The object of this study is a hybrid energy system that integrates the processes of recycling used tires with the use of alternative energy sources to design a sustainable and environmentally safe power generation system. The problem addressed in this study is to find effective methods for recycling waste tires for electricity generation, as traditional recycling methods are energy-intensive and lead to the loss of valuable resources. Three methods of tire processing have been considered: pyrolysis, thermal degradation, and mechanical grinding. The method of electricity generation using pyrolysis has demonstrated high environmental performance due to a significant reduction in greenhouse gas emissions and a high rate of renewable energy (80 %). According to the results of the study, the use of 5 MW pyrolysis furnaces in combination with 500 kW solar panels provides a reduction in dependence on fossil sources, reducing CO2 emissions to 50.0 kg/year. The method has high capital costs (NPC USD 4.2 million), but the cost of energy production (COE USD 0.18/kWh) makes this method competitive in the long run. Thermal degradation provides a balanced approach in terms of energy efficiency (75 %) and environmental performance. Although its CO2 emissions are higher than in pyrolysis, the method makes it possible to obtain additional products that could be used in other industries, thereby increasing economic efficiency. Mechanical shredding has the lowest average energy costs (USD 0.12/kWh) and the lowest CO2 emissions (30.0 kg/year), making it ideal for cost-conscious businesses. The study confirms the possibility of effective integration of renewable sources with tire recycling methods. The practical use of the research results is possible during the implementation of grant projects for the recycling of used tires, and in the work of relevant government structures for devising a policy for the disposal of used tires

Rubbercrete as a sustainable solution for recycling waste tires in concrete: An overview

Due to the rapid growth of the automotive industry, the number of waste tires has been rising dramatically each year. This increase is causing a strain on landfills, as the bulky nature of waste tires, with about 75% of their volume being void, quickly depletes available space of landfills. Furthermore, waste tires are non-biodegradable and, due to their concave shape, provide an ideal breeding ground for insects and harmful rodents, posing a public health risk. Given the limited range of products that can be produced from recycled tires, it is crucial to find economically viable solutions to recycle these tires and use them in mass production of useful materials, such as concrete. Concrete has been chosen by researchers as it is the second most consumed material per capita, after water. Researchers have produced crumb rubber from recycled tires and used it to partially replace fine aggregates in concrete, creating a material known as rubbercrete. Compared to conventional concrete, rubbercrete has better thermal and acoustic properties, is lighter in weight, and more ductile. However, it also shows a reduction in mechanical strengths. This paper provides an overview of rubbercrete, highlighting its key challenges, advantages, and properties.

Recycling waste tires into sustainable biofuel for replacing petroleum fuel in diesel engines using nanoparticles and biohydrogen.

In this paper, the production of pyrolyzed oil in lab scale plant and its possible use in variable speed diesel engine with nanoparticle and secondary fuel oxy-hydrogen gas is investigated. The pyrolyzed oil is produced from waste tires in lab scale plant, and after its distillation, it is blended with neat diesel in the proportion of 20:80 (TDF). The different testing fuels are prepared by mixing nanoparticle CeO2 (NP) at the concentrations 50ppm and 100ppm with blended fuel (named as TDF-NP50 and TDF-NP100). While in the testing phase, the HHO gas is supplied through specially designed venturi at fixed flow rate (fuel designated as TDF-NP50-HHO and TDF-NP100-HHO). The focus of current investigation is to investigate the combined impact of inducting HHO with nanoparticle mixed pyrolyzed blends on engine performance and emissions characteristics. The pyrolyzed blended fuel deteriorate the BTE, BSFC, emissions of HC and NOx while improves the CO emission. The improvement in all the characteristics can be achieved by introducing CeO2 nanoparticle at 50ppm and 100ppm which improves BTE by 15-24%, BSFC by 2.2-4.2%, HC by 8-18%, CO by 7-12%, and NOx by 7-16%. The further improvement can be achieved by inducting HHO gas, which are BTE 11%, BSFC 5-8%, HC 15%, and CO 13-16%. However, the NOx emission is increased by 14-17%. Hence, the waste tire-derived pyrolyzed oil along with green hydrogen and nanoparticles CeO2 can be used as a sustainable transportation fuel in existing CI engine.

Scenario analysis of waste tires from China's vehicles future

As a byproduct of vehicles, tires are utilized in large quantities with the widespread promotion of vehicles. Long-term accumulation of non-degradable waste tires occupies land resources and poses severe environmental threats. Projecting future waste tire volumes provides a scientific basis for preventing excessive accumulation, enables proactive planning of recycling strategies, reduces environmental pollution and promotes waste tire recycling. Using a bottom-up Road Transport Waste Tire Stock model, this study projects vehicle stocks and corresponding annual increases in waste tires from 2002 to 2050. The study reveals that China's vehicle and waste tire stock follows an S-curve growth. Vehicle ownership is projected to increase from 276 million in 2020 to 490–583 million by 2050. Between 2002 and 2030, waste tire generation from vehicles is expected to rise from 4.79 million tons to 18.13–18.57 million tons. By 2050, growth will slow, but the total output will still reach 18.90–19.85 million tons, with cargo trucks contributing 68%. By 2050, Shandong is the leading province in waste tire production, generating 1.82 million tons annually, accounting for 9.1%. Hainan will see the highest growth rate by 2030, with a 40% increase from 2020 levels. The study, based on current policies, presents three recommendations: improving waste tire tracking and recycling systems, implementing region-specific management strategies, and promoting the resource recovery of raw materials from cargo trucks waste tires. These measures aim to enhance waste tire management and foster rubber resource recycling.

Dynamic Behavior of Rubber Fiber-Reinforced Expansive Soil under Repeated Freeze–Thaw Cycles

Large volumes of waste tires are generated due to the rapid growth of the transportation industry. An effective method of recycling waste tires is needed. Using rubber from tires to improve problematic soils has become a research topic. In this paper, the dynamic response of rubber fiber-reinforced expansive soil under freeze–thaw cycles is investigated. Dynamic triaxial tests were carried out on rubber fiber-reinforced expansive soil subjected to freeze–thaw cycles. The results showed that with the increase in the number of freeze–thaw cycles, the dynamic stress amplitude and dynamic elastic modulus of rubber fiber-reinforced expansive soils first decrease and then increase, and the damping ratio first increases and then decreases, all of which reach the turning point at the 6th freeze–thaw cycle. The dynamic stress amplitude and dynamic elastic modulus decreased by 59.4% and 52.2%, respectively, while the damping ratio increased by 99.8% at the 6th freeze–thaw cycle. The linear visco-elastic model was employed to describe the hysteretic curve of rubber fiber-reinforced expansive soil. The elastic modulus of the linear elastic element and the viscosity coefficient of the linear viscous element first decrease and then increase with the increase in the number of freeze–thaw cycles; all reach the minimum value at the 6th freeze–thaw cycle. The dynamic stress–dynamic strain curve calculation method is established based on the hyperbolic model and linear visco-elastic model, and the verification shows that the effect is better. The research findings provide guidance for the improvement of expansive soil in seasonally frozen regions.

The utilization of pulverized waste tire rubber in a soil–cement composite for sustainable compressed earth brick production

This study examined the suitability of blending waste tires with cement in indigenous soil for producing compressed earth bricks (CEB) to achieve a sustainable environment. CEB was produced with clay soil and a combination of cement at 5 and 10% levels with varying dosages of pulverized waste tire at 0, 2.5, 5, 7.5, and 10% mixture. Classification tests were conducted to determine engineering properties such as the particle size distribution, Atterberg limit, specific gravity, optimum moisture and unit weight of the soil. The physical properties of the pulverized tire were evaluated. Moreover, density, water absorption, and compressive strength were determined for hardened CEB samples produced from mixtures of soil and various proportions of blended cement and pulverized waste tire materials. The classification results showed that the soil was silty clay of low plasticity. The density of the CEB samples was observed to increase slightly with the addition of blended cement-tire residue. Furthermore, a considerable improvement in the compressive strength development of the CEB was observed; however, compared with those of the control, the peak compressive strength of the CEB samples was greater when the soil was stabilized with 7.5% pulverized waste tire material and 10% cement. A decrease in the water absorption capacity of CEB was observed with an increase in the amount of pulverized waste tire and cement in the soil mixture. The response models corroborate the experimental findings indicating that amount of waste tire rubber residue and cement had significant effects on the CEB performance. This study ensure the beneficial recycling of waste tires blended with cement in soil for making medium-strength CEB to achieve sustainable, resilient masonry construction applications.Graphical

Characterization of wood plastic composites made with recycled waste tire rubber

Abstract Green materials are currently demanded for construction as well as other products since the 26th UN Climate Change Conference of the Parties (COP26) in 2021. Using renewable and sustainable resources to innovate new materials such as composites is encouraged. This study aimed to investigate the physical and mechanical characteristics of wood plastic composites (WPCs) when adding waste tire rubber as filler for 10% or 20% by weight. The results showed that the density of the WPC samples (50 wt% wood − 50 wt% high density polyethylene) increased with the addition of the waste tire rubber (WTR) while the dimensional stability of samples was reduced. The mechanical properties of the WPC samples were determined, including flexural strength, flexural modulus, elongation at break, tensile strength, tensile modulus, and impact strength. The WTR as filler in the WPC tended to decrease the tensile strength and flexural strength whereas it improved the impact strength of materials. The results indicated that the WTR as recycled material in WPC affected the physical and mechanical properties of the WPCs. Although the use of the WTR in the production of the WPC adversely affects the mechanical properties, the use of 10 wt% WTR was acceptable. The results of the study showed that the addition of the WTR to the WPC production process can be useful for its recycling and for reducing the cost of the WPC.

Characterization of emissions from rubber modified asphalt and their impact on environmental burden: Insights into composition variability and hazard assessment

Rubber modified asphalt (RMA) is a promising avenue for recycling waste tires but faces concerns over hazardous fumes emission during production and construction. This study employs a specialized apparatus to analyze RMA's emission behavior, focusing on crumb rubber size variations under thermal conditions. Ozone Formation Potential (OFP) and Secondary Organic Aerosol Formation Potential (SOAFP) were quantified to evaluate the environmental burden. Results indicate distinct periods of emission behavior for different pollutants, with H2S emissions primarily occurring within the initial 150 min while volatile organic compounds (VOCs) dominate within the first 270 min. The size of rubber particles and thermal exposure duration influence the VOCs microscopic emission characteristics and environmental burdens. Polycyclic aromatic hydrocarbons (PAHs) emerge as the primary contributors to OFP and SOAFP, accounting for nearly 65 % and 25 %−60 %, respectively. High molecular weight aliphatic hydrocarbons (ALHs) also significantly contribute to SOAFP, with PAHs dominating throughout, while ALHs peak during the middle stage. H2S emissions likely stem from rubber, while early VOC emissions originate from rubber, transitioning to petroleum asphalt during the middle and late stages. Asphalt fractions influence emission behavior and property evolution. These findings inform emission suppression strategies and highlight the need for tailored approaches to mitigate emissions effectively.

Experimental study on freeze-thaw failure of concrete incorporating waste tire crumb rubber and analytical evaluation of frost resistance

The incorporation of waste tire crumb rubber into concrete in appropriate size and content not only facilitates the recycling and safe disposal of waste tires but also enhances concrete frost resistance. The exploration of the frost resistance of rubberized concrete is necessary to fill the major gap of standard evaluation guidelines for rubberized concrete. Through rigorous testing and analysis of parameters such as Wn, Pn, and XEdtn of the rubberized concrete incorporating waste tire crumb rubber ranged from 1.0 % to 5.0 % during rapid freeze-thaw cycles, the study clarified the mechanisms by which crumb rubber affects concrete frost resistance. An increase in durability life was noted as rubber content increased, but a decline occurred when rubber content exceeded 3.0 %. Additionally, pretreating crumb rubber further enhanced frost resistance. The durability life of concrete samples with 3.0 % rubber content reached 275 freeze-thaw cycles. Rubberized concrete containing 2.0–4.0 % crumb rubber saw at least a 25-cycle increase by pretreating crumb rubber, and 5.9–17.9 % increase for Pn compared to that of the concrete with untreated crumb rubber reaching the failure state. The inclusion of crumb rubber altered concrete mesoscopic pore structure and the bonding performance of concrete matrix interface, thereby affecting its frost resistance and failure state. A new set of evaluation equations was developed to quantify the frost resistance of rubberized concrete, providing a robust method for assessing the freeze-thaw response of concrete integrated with waste tire crumb rubber. The DFM proposed in this study proves to be more advanced and effective than existing methods for evaluating frost resistance of rubberized concrete.

Study on flexural behavior of concrete slabs strengthened with externally prestressed recycled bead wires

Recycled bead wires were prestressed for reinforced concrete slabs using an innovative anchor that our research group created. In this work, four concrete slab groups were designed: three reinforced groups and one control group. In this work, four concrete slab groups: three reinforced groups, and one control group were designed. The reinforced slabs were subjected to controlled stretching stress of 720 MPa, 900 MPa, and 1080 MPa. Four-point bending static load experiments were performed to verify the recommended reinforcement method and assess the effect of different controlled stretching stress on slab bending performance. This paper presents an analysis of the bearing capacity, crack behaviour, stiffness, and ductility of the specimens. The superior tensile and flexural capabilities of recycled bead wires were used as external prestressing reinforcement materials, as evidenced by the results. The reinforced slab exhibited a maximum increase in ultimate bearing capacity of 142 %, resulting in a significant enhancement of its flexural bearing capacity. The overall stiffness of the slab was successfully increased using recycled bead wires, and the fractures of the reinforced slab exhibited characteristics of fine and dense material. The 'inverted arch' effect of prestressed steel wires efficiently controlled the breadth of the fracture, postponed the onset of cracks, and decreased the degree of specimen damage. The application of more controlled stretching stress was associated with higher carrying capacity, and this also better restricted the development and expansion of cracks. A numerical simulation of four sets of concrete slabs was conducted using ABAQUS, with a subsequent comparative analysis of the results obtained with those of the experimental tests. Furthermore, the feasibility of this type of reinforcement was also confirmed by theoretical analyses of ultimate load-carrying capacity and cracking deflection. Their low-carbon qualities can address issues with waste resources and create new concepts for recycled waste tires.

Improving Asphalt Binder Durability Using Sustainable Materials: A Rheological and Chemical Analysis of Polymer-, Rubber-, and Epoxy-Modified Asphalt Binders

When exposed to sun radiation and heat, asphalt binders age, resulting in reduced flexibility, cracking, and pavement failure. Given the increasing demands of traffic, environmental concerns, and resource scarcity, highway agencies and researchers are actively seeking solutions that meet performance requirements and demonstrate awareness of using non-renewable resources. Epoxy asphalt (EA) promotes sustainability concepts due to its production at significantly lower mixing and compaction temperatures, enhanced durability, improved serviceability, reduced maintenance needs, and successful recycling and reuse in hot asphalt mixtures. Crumb rubber, a widely recognized recycled waste tire material, is considered a viable option for promoting sustainability and enhancing asphalt binder properties. This study aims to enhance the durability and long-term performance of asphalt binders by utilizing sustainable materials. Six types of asphalt binders were employed: PG 67-22 base asphalt binder; styrene–butadiene–styrene (SBS)-modified PG 76-22 and PG 88-22H (3.5% and 7.0% dosage rates, respectively); a hybrid PG 76-22CS-modified asphalt binder prepared with SBS and crumb rubber modifiers; and 25EAB and 50EAB epoxy-modified asphalt binders prepared at 25 and 50% dosage rates, respectively. Results indicate that the sustainable asphalt binders PG 76-22CS, 25EAB, and 50EAB demonstrated comparable or superior performance compared to SBS-modified asphalt binders, as measured by rutting and fatigue factors. Additionally, epoxy asphalt binders had better anti-aging and cracking resistance, as shown by the outcomes of Fourier-transform infrared spectroscopy and linear amplitude sweep tests, respectively. This study contributes valuable insights into the potential of sustainable materials to enhance the overall performance and resilience of asphalt binders.

Influence of Mixing Rubber Fibers on the Mechanical Properties of Expansive Clay under Freeze–Thaw Cycles

With the growth of the transportation industry, large volumes of waste tires are being generated, which necessitates the development of effective solutions for recycling waste tires. In this study, expansive clay was mixed with rubber fibers obtained from waste tires. Triaxial tests were conducted on the rubber fiber-reinforced expansive clay after freeze–thaw cycles. The experimental results of the unreinforced expansive clay from previous studies were used to evaluate the effect of mixing rubber fibers on the mechanical properties of rubber fiber-reinforced expansive clay under freeze–thaw cycles. The results demonstrate that the mixing of rubber fibers significantly reduces the effect of freeze–thaw cycles on the shear strength and elastic modulus of expansive clay. The shear strength and elastic modulus of the unreinforced expansive clay decrease markedly as the number of freeze–thaw cycles increases, while the shear strength and elastic modulus of the rubber fiber-reinforced expansive clay do not exhibit any remarkable change. A calculation model of the deviatoric stress–axial strain curves after freeze–thaw cycles was established. The model describes the deviatoric stress–axial strain behavior of rubber fiber-reinforced expansive clay and unreinforced expansive clay under different confining pressures and different numbers of freeze–thaw cycles.

Flash Pyrolysis of Waste Tires in an Entrained Flow Reactor-An Experimental Study.

In this study, a flash pyrolysis process is developed using an entrained flow reactor for recycling of waste tires. The flash pyrolysis system is tested for process stability and reproducibility of the products under similar operating conditions when operated continuously. The study is performed with two different feedstock materials, i.e., passenger car (PCT) and truck tire (TT) granulates, to understand the influence of feedstock on the yield and properties of the pyrolysis products. The different pyrolytic products i.e., pyrolytic carbon black (pCB), oil, and pyro-gas, are analyzed, and their key properties are discussed. The potential applications for the obtained pyrolytic products are discussed. Finally, a mass and energy balance analysis has been performed for the developed pyrolysis process. The study provides insight into the governing mechanisms of the flash pyrolysis process for waste tires, which is useful to optimize the process depending on the desired applications for the pyrolysis products, and also to scale up the pyrolysis process.

Numerical simulation of the deformation behavior of a composite foundation consisting of rubber particle loess-CFG under dynamic loading

The CFG pile technology is primarily employed for foundation reinforcement, offering cost-saving benefits and demonstrating significant reinforcement effects. Consequently, it has gained widespread utilization. However, due to its unique composition and exceptional strength characteristics, investigating the dynamic properties of rubber particle loess-CFG poses significant challenges. In this study, a numerical simulation approach is employed to investigate the dynamic characteristics of rubber particle loess-CFG and its deformation response under dynamic loading is analyzed. The results indicate that the deformation of rubber particle loess-CFG remains minimal under static loading, while it significantly increases under dynamic loading. However, the vertical and horizontal displacements at the top of the mattress layer are comparatively smaller than those observed in loess-CFG, highlighting their seismic stability. The mattress layer of the rubber particle loess-CFG undergoes vertical compression and deformation, while being horizontally squeezed towards the central region. The horizontal displacement and its variation range are significantly greater than that of the entire pile and the soil between piles. Therefore, it is crucial to analyze the material properties, thickness, and extent of the mattress layer during design in order to mitigate its influence. When subjected to dynamic loading at the base of the model, the rubber particle loess-CFG exhibits a strip distribution of vertical displacement which gradually decreases from bottom to top. Moreover, as focal depth increases, the impact of dynamic loading on foundation deformation diminishes. Consequently, rubber particle loess-CFG provides a dual functionality of enhancing foundation strength while effectively resisting dynamic deformations. These research findings provide a theoretical basis for designing reinforced foundations using rubber particle loess-CFG and offer an innovative approach for recycling waste tire rubber particles.

Modeling and design optimization of dense graded modified crumb rubber asphalt mixtures using response surface methodology

Modification of asphalt pavement materials by using recycled waste tires in form of crumb rubber (CRM) is getting significant importance for saving resources as well as protecting ecosystem. So, in this study the crumb rubber size and percentage content effect on the performance properties of binder and mixtures were evaluated. A detailed experimental program has been performed using design expert software considering the variables like rubber size and content and their responses which were viscosity, Indirect Tensile strength (ITS), Tensile strength ratio (TSR) durability and Resilient Modulus (Mr). The viscosity of control binder with the addition of crumb rubber at high temperatures showed good improvement. The performance properties viz., ITS, TSR and Mr showed similar behavior as the size and content of crumb rubber increased under different loading conditions. The statistical models prepared using the analysis tool were found significant and well fitted based on high R2 (>0.80), high adequate precision value (>4), insignificant lack of fit and low p-value. Analysis of variance (ANOVA) model theoretical results generated by the response surface methodology (RSM) analysis were further validated by the experiments with <5 % of error showing good agreement between theoretical and experimental results. Study results showed that modified binder with 10 % crumb rubber passing sieve No. 40 in mixtures showed good improvement of mechanical properties indicating the potential source of recycled waste material usage in the pavement construction.

Recycling Functional Fillers from Waste Tires for Tailored Polystyrene Composites: Mechanical, Fire Retarding, Electromagnetic Field Shielding, and Acoustic Insulation Properties-A Short Review.

Polymer waste is currently a big and challenging issue throughout the world. Waste tires represent an important source of polymer waste. Therefore, it is highly desirable to recycle functional fillers from waste tires to develop composite materials for advanced applications. The primary theme of this review involves an overview of developing polystyrene (PS) composites using materials from recycled tires as fillers; waste tire recycling in terms of ground tire rubbers, carbon black, and textile fibers; surface treatments of the fillers to optimize various composite properties; and the mechanical, fire retarding, acoustic, and electromagnetic field (EMI) shielding performances of PS composite materials. The development of composite materials from polystyrene and recycled waste tires provides a novel avenue to achieve reductions in carbon emission goals and closed-loop plastic recycling, which is of significance in the development of circular economics and an environmentally friendly society.