Waste Tire Research Articles

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.

A low-cost bonded scrap tire rubber isolator in rural regions: Experimental, numerical and theoretical analysis on mechanical behavior

The utilization of low-cost scrap tire pads (STP) made from recycled tires presents a promising alternative to traditional rubber isolators (i.e., fiber-reinforced elastomeric isolators) in rural construction. However, the STP was limited in application to practicing structures due to stability with a shear strain level of 100 % and the significant variability of the mechanical behavior at the same parameters. For these issues, this paper presents a bonded scrap tire rubber isolators (BSTRIs), based on earthquake demand parameters for rural area buildings. In addition, a series of vertical compression and horizontal shear tests were conducted to evaluate the dependency of mechanical behavior on surface pressure (σ0), the first and the second shape factor (S1 and S2). Then, a finite element (FE) model of BSTRIs was developed and validated. The experimental and FE results show that the σ0, S1, and S2 overwhelmingly effect on mechanical behavior (i.e., critical pressure, vertical stiffness, horizontal stiffness, and damping ratio). Moreover, the new theoretical formulations on critical pressure, vertical stiffness, and horizontal stiffness were developed to evaluate the stability of BSTRIs. Finally, based on experimental result, a nonlinear dynamic response was conducted including the BSTRIs-supported and based-fixed unreinforced masonry (URM) buildings under 22 far-field and 28 near-field seismic excitations. The results indicated that the base shear of the BSTRIs-supported URM were decreased by 66.5 % and 50.1 % in far- and near-field record, respectively, compared with the response of the fixed-base URM building.

Pergaruh Rendaman Pada Marshall Campuran AC-BC Limbah Ban Karet Bekas Sebagai Agregat Pengganti

Utilization of new technologies in asphalt mixture production includes soaking technologies that can enhance mechanical properties of the mixture. This research aims to evaluate pavement vulnerability to water and the environmental quality impact due to waste from used rubber tires as an effort to strengthen pavements by substituting asphalt. The variables studied are variations of used rubber tire waste at 0%, 2%, 3%, and 4% replacing asphalt content in AC-BC mixtures. Testing was conducted using the Marshall method by soaking the mixtures in water for normal duration, 30 minutes, 24 hours, and 72 hours. The test results indicate that higher percentages of used rubber tire waste and longer soaking durations lead to a decrease in AC-BC mixture characteristics. The Marshall value of the AC-BC mixture with 2% used rubber tire waste was found to be superior compared to mixtures with 0%, 3%, and 4%. From the data analysis conducted, it can be concluded that water has a negative influence on the Marshall value reduction of mixtures containing used rubber tire waste, correlating with increased soaking duration.

Study on delamination characteristics and mechanical properties of cemented waste rock backfill with rubber aggregation

Since some phosphorus mines use raw ore as a product and do not conduct beneficiation around the mines. This makes it difficult for the amount of waste rock to prepare enough backfill for the filling of underground mined-out areas. Using rubber particles made of waste tires to replace part of the waste rock aggregate (WRA) can not only solve the problem of insufficient WRA, but also improve the environmental problems caused by the large accumulation of waste tires. However, due to the small density of rubber and high density of waste rock, the phenomenon of segregation delamination may occur in the cemented backfill, thus affecting the mechanical properties of cemented waste rock backfill (CWRB). To this end, the effect of rubber aggregate (RA) on the segregation delamination of CWRB was determined by using the section image analysis method of specimens, and the quantitative index of segregation delamination of cemented waste rock backfill with rubber (CWRB-R) was constructed. The mechanical properties and failure characteristics of CWRB-R were studied by acoustic emission (AE) test under uniaxial compression condition. The experimental results showed that the segregation delamination characteristics of CWRB-R were related to the mass concentration. The higher the mass concentration, the weaker the degree of segregation stratification of the aggregate, the more uniform the distribution of the aggregate, and the less the strength loss of CWRB caused by the incorporation of RA. The incorporation of RA in CWRB not only reduced the uniaxial compressive strength (UCS) of the backfill, but also caused more cracks to be produced during the failure process of the backfill, and the failure form changes from brittle failure to ductile failure.

Dynamic leaching assessment of recycled polyurethane-coated tire rubber for sustainable engineering applications

Assessing the material ramifications of waste tire rubber stands as a pivotal endeavor for its practical utility. Dynamic leaching analysis emerges as indispensable in delineating its potentialities within sustainable engineering domains. Waste materials stemming from tire recycling industries, notably polyurethane-coated rubber (PUcR), may exhibit promising viability owing to attenuated leaching, thus fostering the circular economy paradigm. Towards this end, upflow column percolation leaching tests were conducted on recycled rubber-soil mixture (RSM) alongside PU-coated rubber-soil mixture (PUcRSM). Analysis through Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) unveiled the leaching dynamics of assorted metals in RSM and PUcRSM, notably showcasing markedly diminished cumulative zinc content (by 99.4%) in PUcRSM, coupled with mitigated electrical conductivity, redox potential, and eluate pH. Leveraging HYDRUS-1D for analytical modeling predicated on the advection-dispersion equation further underscored these insights. These findings suggest that waste PUcR presents itself as a viable option, distinguished by its diminished leachability, suitable for a wide array of applications. These applications include vibration damping in infrastructure, tunnel linings, asphalt roads, rubberized concrete, and lightweight backfill materials for bridges and retaining walls, among others. This initiative will contribute to recycling a substantial quantity of over 1 billion used tires produced annually, ultimately supporting the circular economy ethos through assured and adaptable repurposing of waste from tire rubber recycling industries.

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.

Compressive Strength of Paver Block Using Rubber Tyre Waste and Bamboo Fibre Under Extreme Conditions

The utilisation of by-products in paver block production has gained significant attention due to its potential in environmental condition. This research investigates the effect of incorporating rubber tyre waste and bamboo fibre into the fabrication of paver block on compressive strength, water absorption, density and ultrasonic pulse velocity tests. This research comprises two batches of paver blocks fabrications following a 1:2:3 ratio(cement: fine aggregate: coarse aggregate). Batch 1 involves the fabrication of paver blocks by incorporating varying percentages of rubber tyre waste (0, 10, 20, 30, 40 and 50%), which replace a portion of the sand (referred to as rubber paver block). In Batch 2, various dosages of bamboo fibre, used as a reinforcement material were added to the paver block containing 40% rubber tyre waste, which are referred to as rubber-bamboo fibre paver blocks. Nevertheless, the compressive strength of the rubber-bamboo fibre paver blocks was further examined under two simulated environmental conditions: (1) air and dry cycle, and (2) wet and dry conditions. These conditions aim to assess the block’s resistance to temperature fluctuations, moisture effects, and theiroverall durability. The strength of the paver blocks decreases with the additional inclusion of rubber tyre waste. While the utilisation of 0.3% bamboo fibre has shown improvement in its strength performance compared to 0.2% and 0.4%. It suitable to used for non-loading structural applications that require strength below 25 kPa. This study was able to promote sustainable and green construction materials for paving applications through the efficient recycling of waste materials. It aligns with Sustainable Development Goals (SDG) 9 (Industry, Innovation, and Infrastructure) and 11 (Sustainable Cities and Communities).

Green Manufacturing of UHPFRC Made with Waste Derived from Scrap Tires and Oil Refineries

Ultrahigh-performance fiber-reinforced cement-based composite (UHPFRC) made with waste derived from scrap tires and oil refineries was tested in this study. The UHPFRC sample exhibited a maximum compressive strength of about 189 MPa at the end of 28 days. Steel fibers were recovered from scrap tires and were added up to 3% by volume in the UHPFRC samples. Such additions reduced cement flow by 11% but improved compressive strength by 21%. The equilibrium catalyst particles (ECAT) disposed of by oil refineries were used in amounts of up to 15% by weight as a replacement for cement in such UHPFRC samples. These aluminosilicate materials are spherical in shape and have a porous microstructure, which was found to reduce the cement flow by absorbing more free water onto their surfaces. They also reduced the heat and strength developments at early stages. However, the total cost of the final cement-based mixture and associated CO2 emissions were reduced by up to 7% and 15% due to the inclusion of the ECAT particles. These findings help to optimize the ECAT and recovered steel fibers in the UHPFRC mix design, and such waste valorization strategies can help achieve the goal of becoming carbon neutral.

Production of low-sulfur fuels from catalytic pyrolysis of waste tires using formulated red mud catalyst

Waste tires (WT) are produced in millions of tons per annum and their safe disposal is always a major environmental challenge because of fire hazards and the increasing cost of landfills. WT has high organic matter content that can be converted into fuels and chemicals if suitable technologies can be developed. Herein we report the in situ catalytic pyrolysis of WT using formulated red mud catalyst to produce low sulfur fuel that can be fractionated or can be used without fractionation. The in situ catalytic pyrolysis was conducted at 450–550 °C using formulated red mud catalyst. The yield of pyrolysis liquids ranged from 35 to 40 wt%. The liquid was very rich in limonene and long chain aliphatic hydrocarbons. The catalyst was effective in removing the sulfur compounds in the oil through reactive adsorption desulfurization mechanism. The sulfur species reacted with hematite, calcite, sodium hydroxide, and zinc oxide to form sulfides and were retained in the catalyst. The minimum sulfur content of the catalytic pyrolysis oil was 0.38 wt%. After catalyst regeneration in air through combustion, the catalyst activity was restored, and the catalyst was reused.

Influence of recycled rubber and glass aggregates on magnesium sulfate resistance of geopolymers: Physio-mechanical properties and mechanisms

Recycled rubber aggregates (RRA) and recycled glass aggregates (RGA) are sustainable alternatives to natural aggregates. However, the influences of RRA and RGA on the magnesium sulfate resistance of geopolymers remain unclear. Previous studies have focused on the influences of binder type and composition on magnesium sulfate resistance but have neglected the role of aggregates. This study bridges this gap and demonstrates the influences of RRA and RGA on the magnesium sulfate resistance of geopolymers. This study investigated the physical properties, mechanical properties and phases of FA and GBFS-based geopolymers containing 0:10 – 10:0 RRA and RGA after being exposed to 5 % MgSO4 solution for 90 days. The results showed that compared to 100 % RGA, the 90-day length and mass of 100 % RRA increased by 50.48 and 33.22 times, respectively, and the 90-day compressive, flexural and splitting tensile strengths of 100 % RRA decreased by 65 %, 43.28 % and 56.75 %, respectively. However, the changes in length and mass of 100 % RGA were very small, and the mechanical properties even slightly increased rather than decreased. RRA + RGA showed an interval performance between 100 % RRA and 100 % RGA. The different magnesium sulfate resistance of RRA and RGA were attributed to the following mechanisms. RRA caused much higher drying shrinkage of geopolymers than RGA because the soft nature of RRA increased uncoordinated deformation, leading to micro-cracks in the matrix before magnesium sulfate exposure. The pre-existing micro-cracks served as physical transportation paths for external ions to diffuse into the interior of specimens, leading to expansive gypsum crystals formed in these micro-cracks. The accumulation of expansive gypsum crystals enlarged these micro-cracks and facilitated their propagation, leading to the expansion, cracking and degraded mechanical properties. By contrast, RGA reduced drying shrinkage due to its hard nature, which limited the availability of micro-cracks as physical transportation paths for external ions and therefore reduced the formation of expansive gypsum crystals and improved the magnesium sulfate resistance of geopolymers.

In situ desulfurization mechanism of molten salt thermal treatment for waste tires

Pyrolysis is regarded as a practical way for waste tires to achieve waste-to-resource objectives. However, the environmental risk of pollution emissions in product utilization caused by the migration of sulfur is an important issue in the waste tire disposal industry. This study introduced a solution to using the binary molten salt system (NaOH-Na2CO3) as a heat transfer and desulfurization medium for the thermal utilization of waste tires. The results demonstrated that molten salts had in-situ desulfurization capability at 425 °C −575 °C and inhibited the migration of sulfur to gas–liquid-solid products with the total sulfur ratio reduced by 50 % − 67 %. The sulfur-containing radical intermediates could be extensively consumed by molten salt, leading to a low concentration level of H2S and COS in gaseous products. Simultaneously, molten salt blocked the traditional pathway of the sulfhydryl radical with inorganic additives, weakening the sulfur enrichment to char. Additionally, molten salt enhanced heat transfer during pyrolysis, facilitating the decomposition of thiazole and the polymerization of sulfur-containing benzene ring (2,3-dimethyl-thiophene to benzothiophene). The online monitoring further corroborated that COS release was preceded by H2S at high temperatures (>500 °C) along with the full degradation of the waste tires. Higher desulfurization efficiency of molten salt was achieved with feedstocks of small particle size, as it allows for adequate exposure of the reaction contact sites. This approach provides a new opportunity for in-situ desulfurization of waste tire pyrolysis via molten salt thermal treatment.

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.

Use of recycled rubber in carbon black as a filler in ternary blends of NR/BR/SBR for the automotive tire industry

AbstractThis work aims to find the optimal ratio of recycled rubber (RR) in carbon black (CB)/RR filler and determine its influence on the mechanical properties, thermal behavior, and activation energy of ternary rubber based on polyisoprene (natural rubber [NR]), polybutadiene (butadiene rubber [BR]), and styrene–butadiene rubber (SBR) with a constant ratio of 40/40/20 parts per 100 of rubber (phr). The filler used was N330 (60 phr) and a mixture of CB/RR filler in the following proportions: 55/5, 50/10, and 40/20 phr. The activation energy of the examined samples was determined by the rheometric method. The samples were subjected to thermo‐oxidative (at 100°C after 168 h) and γ‐radiation aging (200 kGy). Hardness, tensile strength, and elongation at break were evaluated before and after thermo‐oxidative and γ‐radiation aging. SEM, attenuated total reflectance fourier‐transform infrared (ATR‐FTIR), and TG/DTG techniques were used to characterize NR/BR/SBR composites.The results show that the most optimal CB/RR ratio is 55/5 phr, which is confirmed by the mechanical properties before and after aging and the results for the activation energies of cross‐linking and reversion. The thermal stability of the composite containing 60 phr of the CB and the composite reinforced with 5 phr of the RR in CB/RR filler is almost the same.The results of this research may be applicable in the automotive tire industry since NR/BR/SBR composites are used for automotive tire treads. Another benefit of this research is that the partial replacement of CB with RR contributes to the reduction of tire waste, and thus to the preservation of environmental protection.Highlights Rubber composite NR/BR/SBR = 40/40/20 phr reinforced with CB/RR filler The amount of RR in the CB/RR filler has been changed to 5, 10 and 20 phr The lowest value for Eac has the sample containing filler CB/RR = 55/5 phr The most thermally stable sample is the sample with 5 phr RR in CB/RR filler RR (5 phr) can be applied in CB/RR filler to reinforce NR/BR/SBR composites

Creation of low-waste technologies at Russian Railways through the introduction of the Bars pyrolysis plant

The volume of industrial and household waste is growing annually, for the storage of which agricultural land is being withdrawn. Waste produced by Russian Railways can cause the destruction of natural ecosystems and lead to the extinction of species.To reduce the impact on natural ecosystems, Russian Railways financed the construction of the largest waste recycling plant in Russia. The uniqueness of the plant lies in its closed-loop processing system without oxygen access. No harmful substances are released into the atmosphere during the combustion process. This method of waste disposal is intended for the processing and disposal of tires, rubber-containing, polymer-containing waste, oil sludge and waste oils.Introduction of modern waste recycling technologies (Bars pyrolysis plant) by all divisions of JSC Russian Railways, it will help reduce the negative impact on the environment, will allow you to quickly and efficiently dispose of hazardous waste, as well as be cost-effective by obtaining secondary raw materials that will give the company profit and pay off the cost of installing equipment.

Characteristics and Applications of Waste Tire Pyrolysis Products: A Review

The review considers the environmental problem of generation, accumulation and utilization of waste tires in Ukraine and the world. It is established that waste tires can serve as a valuable raw material for obtaining fuel components and technical/individual chemicals for further industrial processing. One of the promising methods for the rational utilization of waste tires may be their pyrolysis. The pyrolysis process of waste tires produces gaseous, liquid and solid carbonized residue. At the same time, there is no ideal universal technology for the use of waste tire pyrolysis products without preliminary treatment/purification methods. The main characteristics, processing methods and applications of products obtained from the pyrolysis of waste tires are briefly considered.

The investigation on targeted micro-surface treatment methods for waste tires recycling in cementitious construction materials

Defects in the interfacial transition zone (ITZ) between recycled tire rubber and cement matrix obstacle to the large-scale application of sustainable rubberized cementitious materials. This paper proposed and evaluated different targeted treatment methods for micro-surface properties enhancement of rubber aggregate by the Polyvinyl Alcohol (PVA), Polyethylene Glycol-200 (PEG), and Hydroxypropyl methylcellulose (HY) polymer solutions through copolymerization and drafting processes. The optimum modification condition was determined through the FT-IR analysis, contact angle, and surface free energy of treated rubber aggregates and the micro-surface morphology and element distribution were analyzed by using ESEM and EDX, respectively. The flexural strength and pore size distribution of steel fiber-reinforced rubberized mortar with relatively high replacing volumes (20%, 40%, and 60%) were evaluated to validate the targeted micro-surface modification efficiency. The surface microstructure and hydrophilic properties of rubber aggregate were significantly improved and the mechanism for enhancing the interface adhesion between rubber and cement matrix was revealed.

Turning waste tyres into carbon electrodes for batteries: Exploring conversion methods, material traits, and performance factors

AbstractWaste tyres (WTs) are a major global issue that needs immediate attention to ensure a sustainable environment. They are often dumped in landfills or incinerated in open environments, which leads to environmental pollution. However, various thermochemical conversion methods have shown promising results as treatment routes to tackle the WT problem while creating new materials for industries. One such material is WT char, which has properties comparable to those of carbon materials used as an active electrode material in batteries. Therefore, a systematic review of the various thermochemical approaches used to convert WTs into carbon materials for electrode applications was conducted. The review shows that pretreatment processes, various process routes, and operating parameters affect derived carbon properties and its respective electrochemical performance. WT‐derived carbon has the potential to yield a high specific capacity greater than the traditional graphite (372 mAh g−1) commonly used in lithium‐ion batteries. Finally, the review outlines the challenges of the process routes, as well as opportunities and future research directions for electrode carbon materials from WTs.

Technoeconomic analysis: the potential and opportunities of transforming Saudi Arabian scrap tires into synthetic fuel via vacuum pyrolysis

Environmental hazards linked with scrap tires have been a great concern for the Saudi government. The Kingdom of Saudi Arabia has a Vision 2030 project with an aim to produce 50% of its energy through renewable energy resources. The tire market in the country reached 22.2 million units in 2022 and is expected to increase up to 24.9 million in 2028 with a growth rate of 2.11%. This study used a vacuum pyrolyzer for transforming scrap tires into tire-derived oil (TDO), along with other products such as synthesis gas (syngas) and carbon black. It provides a feasible way of transforming scrap tires into synthetic fuel via vacuum pyrolysis (a thermochemical approach). Vacuum pyrolysis of scrap tires at temperature 350–400oC yields 45%–55% derived oil, 10%–15% steel wires, 30%–35% carbon black, and 10%–15% non-condensable gases. The heating value of the obtained tire-derived oil is 32–37 MJ/kg, which is somehow less than that of diesel, which has an energy value of 44–46 MJ/kg. Such products are expected to be obtained after the successful adaptation of advanced techniques such as thermochemical approaches and can successfully be used as an alternative to fossil fuels. Based on the scrap tire produced in the country, if Saudi Arabia can process 22.2 million units of tires (trucks and passenger cars) annually through vacuum pyrolysis, it can earn approximately $47.40 million annually (or $2.14 per tire) through tire pyrolysis. Utilization of carbon black (recovered from scrap tire pyrolysis) in manufacturing tires can save approximately 2.5 tons of CO2 production compared to per ton production of new (virgin) carbon black. This study suggested pyrolysis to be a viable recycling and waste tire management technique, and it can be an independent profitable operation in Saudi Arabia and helps in meeting the Saudi Vision 2030.

Waste tire-derived graphene modified carbon as anodes for sodium-ion batteries

The rational disposal of waste tires poses a ubiquitous challenge globally. Pyrolytic carbon black, a solid by-product produced through pyrolysis, has great application prospects. Carbon-based materials are regard as the most potential commercial anode materials for sodium-ion batteries (SIBs)， which features cheap, environmentally friendly, and low reaction potential. In this study, three-dimensional vertical graphene composite (TCBp@VGSs) was synthesized from waste tires. The graphene with higher defectiveness offers an increased number of active sites for Na+, while the vertically aligned graphene facilitates rapid electron transfer. As a result, the TCBp@VGSs electrode demonstrates the ability to maintain a reversible capacity of 252.7 mAh g−1 after 100 cycles at a current density of 0.2 A g−1. Furthermore, it exhibits a sustained rate performance of 105.4 mAh g−1 at a current density of 5 A g−1. Moreover, even after 1900 cycles at a current density of 1 A g−1, a reversible capacity of 171.5 mAh g−1 is retained, showcasing good stability and a significantly higher capacity compared to TCBp-1100. This study introduces novel approaches for the high-value utilization of solid-phase by-products from waste tires, offering certain economic benefits, and contributes fresh insights into the advancement of SIBs anodes.

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.