Waste Tire Research Articles

Effects of metakaolin and waste tire aggregate on the properties of pumice-based lightweight geopolymer

The lightweight geopolymers (LWGPs) were prepared using fly ash (FA) and pumice aggregates, and their sustainability was enhanced by recycling waste tire aggregates (WTAs). The results show that substituting pumice aggregate with WTA reduces the density of LWGP and improves its fluidity. However, this substitution is detrimental to the development of the strengths and durability of LWGP, but it is beneficial to the improvement of thermal insulation performance. The further use of metakaolin to replace FA enhances the performance of WTA-based geopolymer, especially improving its mechanical properties and durability. When 10% of FA is replaced by metakaolin, the compressive strength of LWGP increases by 5.5%–40.4%, and the residual strength after sulfate attack, freeze-thaw cycle and high temperature treatment is significantly improved. Using a small amount of metakaolin effectively mitigates the negative impact of WTA on the performance of LWGP. Utilizing WTA effectively reduces the total cost and carbon emission of LWGP production. Compared to plain LWGP, the mixtures with 15%–45% WTA exhibit a relative reduction in cost and carbon emission by 4.5%–13.4% and 1.3%–4.0%, respectively. Although the inclusion of metakaolin escalates both the cost and carbon emissions, its incorporation significantly enhances the overall performance of LWGP.

Technical and Economic Analysis of a Novel Integrated Energy System with Waste Tire Pyrolysis and Biogas

To reduce dependence on fossil fuels, cope with the growing energy demand, and reduce greenhouse gas emissions, this paper innovatively designs a novel integrated energy system integrating anaerobic digestion of animal manure, fuel cell technology, gas turbine, and tire pyrolysis. The system maximizes the energy potential of biogas while synergistically treating waste tires, improving waste management’s flexibility, efficiency, and economic viability through multiple outputs such as electricity and by-products, subsystem synergies, equipment sharing, and economies of scale. Thermodynamic performance and economic feasibility are analyzed using Aspen Plus V14 simulation modeling, ensuring the system’s technical and economic viability. In this study, the simulation model of the system is established, and the techno-economic benefits of the system are analyzed. The simulation results show that the net electric power output of the system is 444.79 kW. Combined with the contribution of pyrolysis products, the system’s total efficiency reaches 70.88%. In only 4.79 years, the initial investment can be recovered, and in its 25-year service life, the system has realized a profit of 2,939,130 USD. The system realizes the energy and quality matching between different thermal processes through indirect collaborative treatment of different solid wastes, improves the conversion efficiency of biogas energy, co-treats waste tires, and reduces environmental pollution.

Mechanical properties of double-solid waste cement stabilized Macadam

Cement stabilized macadam base has high strength and excellent bearing capacity, but the problems of water-temperature sensitivity, easy shrinkage cracking and large demand for aggregate limit the further development and application of cement stabilized macadam base. At the same time, with the economy development, the increase of solid waste, such as waste tires and construction waste, has caused great pressure on the ecological environment. In order to ensure better mechanical properties and shrinkage resistance of the cement stabilized macadam on the basis of full use of solid waste. In this paper, mechanical properties tests such as unconfined compressive strength, splitting strength, compressive resilient modulus and shrinkage properties tests such as dry shrinkage and temperature shrinkage were conducted. Double-solid waste cement stabilized macadam mixture were prepared by partially replace fine and coarse aggregates with waste crumb rubber of different mesh and replacement ratios and recycled concrete aggregate of different replacement ratios, and their properties were investigated. The experimental results show that: (1) The good elasticity and toughness of waste crumb rubber can improve the crack resistance of cement stabilized macadam mixture. While the mechanical properties such as unconfined compressive strength and splitting strength will be reduced. (2) The mechanical properties of double-solid waste cement stabilized macadam mixture can be improved by partially replacing coarse aggregate with appropriate amount of recycled concrete aggregate with porous and rough surface, but it will adversely affect its shrinkage resistance. (3) The recommended particle size and replacement ratio of waste crumb rubber in double-solid waste cement stabilized macadam mixture are 40 mesh and 0.5%, respectively, and the recommended replacement ratio of recycled concrete aggregate is 75%. The mechanical properties indexes of double-solid waste cement stabilized macadam mixture can meet the specification requirements.

Viable Use of Tire Pyrolysis Oil as an Additive to Conventional Motor Oil: A Tribological and Physical Study

Stockpiled end-of-life tires (ELTs) pose a serious environmental concern. In the current investigation, ELT pyrolysis oil (i.e., pyro-oil) was studied as a potential additive to conventional motor oil. The pyro-oil samples were mixed in different concentrations of 10 to 50 wt.% with commercial virgin motor oil to obtain a lubricant mixture. Chemical analyses were performed for the tire-recycled derivative material, as a potential route to utilize pyro-oils, valorize ELT waste, and reduce production costs of motor oil lubricants. Rheological examinations were performed to explore the impact of the pyro-oil on the rheological properties of the motor oil under several shearing rates and temperatures. Tribological analyses of the lubricant mixtures and the pure motor oil were accomplished to study the influence of the pyro-oil additive on the tribological behavior of motor oils. Lastly, thermal stability and wettability examinations were executed to assess the thermal and wetting properties of lubricant mixtures. The obtained results showed that adding a low concentration of the pyro-oil (≤10%) will sustain the motor oil’s chemical, wettability, thermal stability, rheological, and tribological properties, signifying a viable application of recycled ELTs and helping to reduce their environmental and economic impact. These findings offer a feasible route of use in the future to obtain low-cost oils with market specifications, utilizing pyro-oil as a sustainable and environmental oil additive.

The Effect of Adding Waste Tire Rubber on Compressive Strength, Impact Resistance, and Damping Ratio of Fiber-Reinforced Foamed Concrete

Research was conducted to investigate the effects of incorporating optimal proportions of Waste Tire Rubber (WTR) on the compressive strength, impact resistance, and damping of fiber-reinforced Foamed Concrete (FC) modified with a Super-Plasticizer (SP). In this study, four FC types with a density of 1100 kg/m3 were produced: conventional FC, modified FC with SP, polypropylene (PP) fiber-reinforced FC, and fiber-reinforced rubberized FC (containing SP, PP, and WTR). To evaluate the effect of density on the FC properties, two additional fiber-reinforced rubberized FC mixtures were produced with densities of 800 and 1400 kg/m3. The sand in the FC was partially replaced with WTR at optimum ratios of 50% for coarse WTR (4.75–10 mm) and 34% for fine WTR (≤ 2.36 mm). Additionally, 53 kg/m3 of cement was substituted with fly ash. The results indicated that the addition of SP enhanced the properties of the fresh and hardened FC. For a given density of 1100 kg/m3, adding WTR led to decreased consistency and strength while increased the impact and damping compared to the reference containing only SP and PP. However, the fiber-reinforced rubberized FC mix with SP showed improvements of 79.5%, 3700%, and 21.45% in compressive strength, impact resistance, and damping, respectively compared to conventional FC (without SP and PP). With the exception of the damping ratio, the compressive strength and impact resistance increased when the rubberized FC density was elevated.

Management and Disposal of Waste Tires to Develop a Company for the Manufacture of Products Based on Recycled Rubber in Tamaulipas, México

Currently, the disposal of waste tires is considered one of the priority environmental and public health problems worldwide. Every year, more than 1.4 billion unused tires are placed in landfills. Population growth, economic development, and a strong demand for vehicle production in the automotive industry increase this problem. In Mexico, nearly 36 million unused tires are deposited in landfills or clandestine deposits, the vast majority being burned or accumulated in the open air. The lack of regulations in the handling, disposal, and recycling of tires creates a worrying panorama for environmental care and the problems that this entails. The objective of this work is to propose a viable alternative for the final disposal and recycling of waste tires through the implementation of a company for the manufacture of products based on recycled rubber in the state of Tamaulipas, Mexico, reducing environmental pollution by these wastes and generating sources of employment through a sustainable company. For this purpose, a study was carried out in Tamaulipas, Mexico, through surveys to determine the number of tires that can be obtained and determine the feasibility of the business; subsequently, a prediction was made using simulation software to design and estimate the expected production in the manufacture of parking bumpers using two scenarios with two and four workers. Likewise, specialized software was used to optimize waste tire collection routes from the different tire stores to the company’s location. The results show that with an optimal design of the tire collection routes, up to 483 tons of waste tires can be recovered per year, representing 10% of the total unused tires in Tamaulipas. Because it is an environmental and social problem, installing a company manufacturing products based on recycled rubber is feasible and has a high probability of success for the region studied. According to the simulation, employing four workers increases productivity and decreases manufacturing costs. Through the simulation, three tire collection routes were determined considering the total number of tire stores in the city where the company is located.

Accelerated carbonization of waste tire via microwave heating: Carbon anode derived from waste tire for sodium-ion battery

Accelerated carbonization of waste tire via microwave heating: Carbon anode derived from waste tire for sodium-ion battery

CO2-induced co-pyrolysis of Pennisetum hydridum and waste tires: Multi-objective optimization of its synergies and pyrolytic oil, char and gas outputs

CO2-induced co-pyrolysis of Pennisetum hydridum and waste tires: Multi-objective optimization of its synergies and pyrolytic oil, char and gas outputs

Dynamic Structural Responses of Tunnel Surrounding Disturbed Sand Retrofitted by Waste Tire–Derived Aggregate with Presence of Piles

Dynamic Structural Responses of Tunnel Surrounding Disturbed Sand Retrofitted by Waste Tire–Derived Aggregate with Presence of Piles

Performance enhancement of asphalt binders using upcycled waste tires and plastics: A UAE-based study on alternatives to SBS-modified binders

Performance enhancement of asphalt binders using upcycled waste tires and plastics: A UAE-based study on alternatives to SBS-modified binders

Study on waste tires pyrolysis characteristics and high-value oil: Effects of pyrolysis parameters and catalyst

Study on waste tires pyrolysis characteristics and high-value oil: Effects of pyrolysis parameters and catalyst

Design of experiments method into upgrading pyrolytic oil for sustainable aviation fuel additives by hydrotreating and hydrocracking.

Recycling waste to produce liquid fuels for the automotive and aviation industries is a major global concern, especially in light of the ongoing energy crisis. Because waste is used in thermal conversion processes, the resulting liquid products often require additional processing to reduce their density and viscosity, and to remove oxygenated compounds or pollutants that hinder further utilization. Catalytic hydrogenolytic reactions such as hydrodeoxygenation (HDO) and hydrocracking (HC) have been extensively applied to upgrade pyrolysis oils. Selecting the appropriate catalyst and optimizing the process operating conditions are crucial for yielding high-quality fuel. Design of experiments (DOE) and analysis of variance (ANOVA) can identify the primary factors of the process and their possible interactions. This research focuses on the conversion of pyrolysis oil derived from car tires into jet fuel and aims to determine the optimal HDO and HC conditions to maximize the concentration of the kerosene fraction. Hydrodeoxygenation and hydrocracking reactions using NiMo/γ-Al2O3 catalysts are examined under varying temperature, pressure, and time conditions. The compositions of the raw tire pyrolysis oil (TPO) are mainly characterized by heteroatom content, aromatic compounds, olefins and acetylenes, alkanes, and cycloalkanes, which play key roles during HDO and HC procedures. Subsequently, the distillation and separation of the fuel fractions are carried out to determine the quality of the product.

Beneficial effect of recycled tire powder incorporation on the tensile performance of strain-hardening alkali-activated concrete

Beneficial effect of recycled tire powder incorporation on the tensile performance of strain-hardening alkali-activated concrete

Microstructural modifications in bitumens rejuvenated by oil from pyrolysis of waste tires

Microstructural modifications in bitumens rejuvenated by oil from pyrolysis of waste tires

Enhancing Concrete Properties With Rubber Additives: Experimental Analysis And Performance Evaluation

This research investigates the effect of adding recycled rubber to concrete mixes as part of efforts to enhance environmental sustainability and improve the mechanical properties of concrete. The study focuses on evaluating the mechanical and physical performance of rubberized concrete by analyzing its properties such as compressive strength, tensile strength, and workability. Partial replacement of rubber by 0% to 15% of fine aggregate in concrete was studied, with standard tests conducted to determine the effect of rubber on overall performance. The importance of the research lies in providing a dual solution of reducing environmental waste from used tires, while improving some properties of concrete in non-structural applications. The results show that rubberized concrete achieves important advantages such as improved flexibility, abrasion resistance, and light weight, despite a slight decrease in compressive strength. The research also highlights the potential of using rubberized concrete in non-structural applications such as pavements, road barriers, and shock absorption systems. The research concludes by recommending further studies to improve the adhesion between rubber and concrete mix components, while exploring innovative applications to expand the use of rubberized concrete in sustainable construction projects.

Simultaneous Adsorptive Desulphurization and Denitrogenation in Crude Tire Pyrolysis Oil Refining

Pyrolytic oil usually contains high nitrogen and sulphur content which reduces its efficiency in addition to posing crucial environmental and health concerns. Hence the need for desulphurization and denitrogenation of pyrolytic oil obtained from waste tire for efficient application. Freshly prepared Ni-Cr adsorbent impregnated with TiO2-SiO2 catalyst was used as the adsorbent in the treatment of the pyrolytic oil through adsorption process. Effect of operating time and catalyst ratio were investigated. The result showed that both operating time and catalyst ratio influenced the percentage removal of sulphur and nitrogen. TiO2:SiO2 catalyst ratio of 2:3 gave 78.38%sulphur removal while ratio of 5:0 gave 89.80% nitrogen removal. The effect of time indicated that 78.84% and 93.98% removal of sulpur and nitrogen were obtained respectively after 120 minutes. For optimal simultaneous removal of both sulphur and nitrogen, a mixing ratio of 1:4 was obtained. The study showed that Ni-Cr/TiO2-SiO2 can be an effective adsorbent in desulphurization and denitrogenation of crude tire pyrolytic oil.

From Waste to Fuel: Coprocessing Waste Tire Pyrolysis Oil with Atmospheric Gas Oil to Produce Ultralow-Sulfur Diesel

From Waste to Fuel: Coprocessing Waste Tire Pyrolysis Oil with Atmospheric Gas Oil to Produce Ultralow-Sulfur Diesel

Sustainable, greener and safer asphalt pavements considerations under tropical conditions

PurposeThe main aim of this paper was to investigate the possibility of obtaining green sustainable asphalt mixes by using two different recycled materials: reclaimed asphalt pavement (RAP) and crumb rubber (CR) from scrap tyres. With the numerous environmental and social benefits brought about, the use of modified hot mix asphalt and warm mix asphalt (WMA) mixtures should be the focal point of the construction policies in developing countries. Adaptation of this solution would result in an economical and sustainable green pavement with high resilience and safer workspace area with less fumes and odours for asphalt workers.Design/methodology/approachExperimental work-testing one control mix and modified design mixes, which have been modified either by RAP, CR, a WMA additive or any combination of the latter three products.FindingsFrom the different test results, it can be rightly concluded that the addition of CR and RAP do enhance the properties of asphalt mixes to a varying degree. While CR adds a certain flexibility to the mixes and reduces the voids present, the presence of RAP has an amplified effect on stability, especially when coupled with rubberised WMA.Research limitations/implicationsMarshall method still used as opposed to Superpave method in developing countries (Mauritius, Jordan here in).Originality/valueA study for Tropical Island and its uniqueness to add to present knowledge.

Physico-Mechanical Properties of Alkali-Activated Based Composites Using Recycled Tire Fibers

Used tires (UTs) are a global problem, especially in developing countries due to inadequate management systems. During retreading, when the worn tread is replaced, waste is generated in the form of tire fibers (TFs) and particles, which can be reused as raw materials to produce economically and environmentally low-cost prefabricated elements. Using TFs as a lightweight aggregate in nonstructural geopolymer-based elements is a sustainable valorization option. This study aims to valorize used tires by incorporating them as TFs into lightweight geopolymer mixes and analyzing their physico-mechanical, thermal, and thermography properties for building and civil engineering applications. The geopolymer is produced from a precursor (spent catalyst residue from catalytic cracking, FCC) and an alkaline activator composed of rice husk ash (RHA), sodium hydroxide, and water. The control sample’s (mortar with siliceous sand, CTRLSIL) compressive strength came close to 50 MPa, while the TF mixes ranged from 32 to 3 MPa, which meet the masonry standards. The thermal conductivity and thermography analyses showed that increasing the TF content reduced the heat transmission and achieved a similar performance to expanded-clay concrete and better performance than for conventional concrete.

Geotechnical characterization of soil-rubber mixtures with well-graded gravel

Shredded rubber from waste tyres has progressively been adopted in civil engineering due to its mechanical properties, transforming it from a troublesome waste into a valuable and low-cost resource within an eco-sustainable and circular economy. Granular soils mixed with shredded rubber can be used for lightweight backfills, liquefaction mitigation, and geotechnical dynamic isolation. Most studies have focused on sand-rubber mixtures. In contrast, few studies have been conducted on gravel-rubber mixtures (GRMs), primarily involving poorly-graded gravel. Poorly-graded gravel necessitates selecting grains of specific sizes; therefore, from a practical standpoint, it is of significant interest to examine the behaviour of well-graded gravel and shredded rubber mixtures (wgGRMs). This paper deals with wgGRMs. The results of drained triaxial compression tests on wgGRMs are analysed and compared with those on GRMs. Stress-strain paths toward the critical state and energy absorption properties are evaluated. The tested wgGRMs exhibit good shear strength and remarkable energy absorption properties; thus, they can be effectively utilised in several geotechnical applications.