Recycled Tire Rubber

Recent years have been shadowed by an increase in the adoption of recycled transportation and building materials, focusing on the adoption of damped waste materials. Numerous waste materials, including glass, plastic, and tire rubber, have been adopted in conjunction with standard resources as recycled aggregates or a binder improvement, depending on the application. Rubber from powdered tires may be added as a flexible aggregate in a concrete block, reducing the likelihood of brittle failure and increasing the concrete's capacity to absorb more significant amounts of energy before failure. Due to the high elastic modulus of rubber particles, the substitute of coarse aggregate for crumb rubber may significantly impact the strength characteristics of concrete, resulting in concentrated stress, strain, and bonds between the rubber particles and the cement. Rubber granules are an acceptable substitute for coarse aggregate in developing responsive concrete. On the contrary, the use of finely graded rubber may result in a tensile behavior with substantial deformations before the complete disintegration of the concrete. It may have a more negligible impact on the loss of strength of the concrete. According to the experiment, despite the experimental concern on safety, it aims to assess rubberized concrete's performance and thus potential use in the concrete making to aid in environmental conservation.

Recycling of ‘End of Life Tyres’ (ELT) is one of the major environmental concerns faced by the scientific community and the government organisations, worldwide. Every year, an estimated one billion tyres reach their end of life, out of which only about 50% are currently being recycled and the remaining form part of the landfills. Therefore, there is an urgent need to improve the existing and develop new applications of recycled tyre products to address this shortfall in the utilisation rate of the ELT. One application which is actively being researched is the use of waste tyre rubber as a partial replacement of conventional aggregates in concrete applications. Although it shows tremendous potential, it comes with its own challenges such as weak inherent strength of the rubber and poor bond performance with the cement matrix, which hinders its use as an aggregate in large quantities. To overcome this challenge, researchers have looked at various rubber treatment methods that not only improve the bond performance but also significantly improve the mechanical properties of rubber concrete. This review paper considers the effect of rubber particle size, percentage replacement and various treatment methods on different mechanical properties of rubber concrete, studied over the last 30 years. However, to be accepted by the concrete industry, the researchers have to come up with a rubber treatment method that can address the concerns of high flammability and the resultant release of noxious gases from the rubber particles, when exposed to fire.

This study aims to examine the effect of various advanced catalysts on tire waste pyrolysis oil using a small pilot-scale pyrolysis reactor with a capacity of 20 L. The catalytic pyrolysis with activated alumina (Al2O3) catalyst produced maximum liquid oil (32 wt.%) followed by activated calcium hydroxide (Ca(OH)2) (26 wt.%), natural zeolite (22 wt.%) and zeolite (H-SDUSY) (14 wt.%) catalysts, whereas liquid oil yield of 40% was obtained without catalyst. The gas chromatography-mass spectrometry results confirmed the pyrolysis liquid oil produced without catalyst consist of up to 93.3% of mixed aromatic compounds. The use of catalysts decreased the concentration of aromatic compounds in liquid oil down to 60.9% with activated calcium hydroxide, 71.0% with natural zeolite, 84.6% with activated alumina, except for synthetic zeolite producing 93.7% aromatic compounds. The Fourier-transform infrared spectroscopy data revealed that the mixture of aromatic and aliphatic hydrocarbon compounds were found in all liquid oil samples, which further confirmed the gas chromatography results. The characteristics of pyrolysis liquid oil had viscosity (1.9 cSt), density (0.9 g/cm3), pour point (-2 °C) and flash point (27 °C), similar to conventional diesel. The liquid oil had higher heating values, key feature of a fuel, in the range of 42-43.5 MJ/kg that is same to conventional diesel (42.7 MJ/kg). However, liquid oil requires post-treatments, including refining and blending with conventional diesel to be used as a transport fuel, source of energy and value-added chemicals.

In this study, the behavior of the recycled plastic, glass and rubber tire as partial replacement of coarse aggregate in concrete have been investigated. Polyethylene terephthalate (PET) bottles, one of the waste plastic types, broken glass of bottles and rubber tires are used for these purposes. The reason to choose these to transfer the recycles materials into valuable product and to solve the problem of dumping the tons of plastic waste, broken glass and rickshaw tires. In this study compressive strength of cylinder concrete specimens were carried out at 7 and 28 days curing. Six concrete mixes have been studied, those are-reference specimens with no recycled material (CS0), specimens with 15% plastic (CSP15), specimens with 15% (CSR15) and 30% (CSR30) tire, specimens with 15% (CSG15) and 30% (CSG30) glass. Total 24 cylindrical specimen of 8"x4" were tested for compressive strength. The order of compressive strength was CS0 > CSG30 > CSG15 > CSR15 > CSR30 > CSP15. The Study found that compressive strength of concrete mix decreases with the increase of plastic and rubber content. However, compressive strength of concrete increases with the increase of glass content. Plastic material have low bonding with cement in concrete and perform poorly. On contrary, glass works very well with concrete and compressive strength of concrete reduces with the increase of rubber content.

Wastes are a serious concern and industry produces large quantities and different types of rubber waste. Issues arise when recycling high percentages of rubber compounds in bituminous mixtures, also because of the different physical, chemical properties and due to different mechanistic properties. In the light of the above, the objectives of the study described in this paper were confined into the analysis of different mix types (porous asphalt concretes, PA, dense-graded asphalt concretes, DG, cold bituminous mixes, CM) containing exhausted rubber hose pipes (RH, obtained from extinguishers at the end of their life cycle) or waste rubber tyres (WRT). Different crumb rubber types were added following the dry process. Very high percentages of crumb rubber (CR) were used. Consequently, composition, surface performance (friction, texture, permeability, acoustic absorption) and mechanical performance (rutting) of the above bituminous mixes were investigated. All the mixtures were manufactured with polymer modified binder. The results highlight a comparable behaviour among the different mixtures, although several differences emerged. Results and outcomes can benefit researchers and practitioners.

District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand – outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations. Abstract In the Kingdom of Saudi Arabia (KSA), millions of worshippers come from across the globe to perform religious rituals of Pilgrimage (Hajj) and Umrah. Madinah-tul-Munawara is one of the holiest city, where pilgrims come after performing rituals in Makkah. In this city, most of the collected municipal solid waste (MSW) is disposed of in the landfills after a partial recycling of paper, cardboard, and metals (~10-20% of total MSW). The Saudi's government has recently launched a new policy of Vision 2030, which outlined the safeguard of local environment through increased efficiency of waste recycling and management, pollution prevention strategies and generating renewable energy from indigenous sources, including the waste. Currently, the recycling practices in KSA are mainly regulated by an informal sector through waste pickers or waste scavengers. This has led to the need of recycling schemes, especially in the holiest cities of Makkah and Madinah through a public-private partnership (PPP). Huge amounts of energy can be conserved, that would otherwise be spent on raw material extraction, transportation, and manufacturing of materials, through recycling into the same materials. Around 10,009 TJ of energy can be saved through recycling of 24.21% of MSW in Madinah city, including glass, metals, aluminum, cardboard, and paper. It is estimated that around 10,200 tons of methane (CH4) emissions and 254,600 Mt.CO2 eq. of global warming potential (GWP) can also be saved. In addition, carbon credit revenue of US $5.92 million, and landfill diversion worth of US $32.78 million can be achieved with a net revenue of US $49.01 million every year only by recycling 24.21% of MSW in Madinah city. The waste recycling doesn't require high technical skills and labor, and complicated technologies for large-scale implementation, and therefore, can be implemented easily in the holiest cities of Makkah and Madinah to achieve multiple economic and environmental benefits. Abstract In the Kingdom of Saudi Arabia (KSA), millions of worshippers come from across the globe to perform religious rituals of Pilgrimage (Hajj) and Umrah. Madinah-tul-Munawara is one of the holiest city, where pilgrims come after performing rituals in Makkah. In this city, most of the collected municipal solid waste (MSW) is disposed of in the landfills after a partial recycling of paper, cardboard, and metals (~10-20% of total MSW). The Saudi's government has recently launched a new policy of Vision 2030, which outlined the safeguard of local environment through increased efficiency of waste recycling and management, pollution prevention strategies and generating renewable energy from indigenous sources, including the waste. Currently, the recycling practices in KSA are mainly regulated by an informal sector through waste pickers or waste scavengers. This has led to the need of recycling schemes, especially in the holiest cities of Makkah and Madinah through a public-private partnership (PPP). Huge amounts of energy can be conserved, that would otherwise be spent on raw material extraction, transportation, and manufacturing of materials, through recycling into the same materials. Around 10,009 TJ of energy can be saved through recycling of 24.21% of MSW in Madinah city, including glass, metals, aluminum, cardboard, and paper. It is estimated that around 10,200 tons of methane (CH4) emissions and 254,600 Mt.CO2 eq. of global warming potential (GWP) can also be saved. In addition, carbon credit revenue of US $5.92 million, and landfill diversion worth of US $32.78 million can be achieved with a net revenue of US $49.01 million every year only by recycling 24.21% of MSW in Madinah city. The waste recycling doesn't require high technical skills and labor, and complicated technologies for large-scale implementation, and therefore, can be implemented easily in the holiest cities of Makkah and Madinah to achieve multiple economic and environmental benefits.

Featured Application: The mechanical behaviour of an agricultural pneumatic tyre was investigated experimentally and the results, linearized in adjacent stretches, were used to tune a finite element model, including both the carcass and the air.

Abstract: The mechanical behaviour of an agricultural tyre is a matter of extreme interest as it is related to the comfort of operators, to the adherence of agricultural machines, and to the compaction of agricultural soil. Moreover, the deformability of the tyres plays a fundamental role in vehicle stability in terms of side rollover. The behaviour of a loaded tyre during its deformation is complex, due to the combined contributions of the carcass components, the tread rubber and the air contained within it. Therefore, this study proposes an experimental-numerical approach for the mechanical characterization of agricultural tyres based on real-scale experiments and matches these results with a finite-element (FE) model. The tyre flattening in the elastic field has been described using two coefficients (Young's modulus "E", Poisson's ratio "ν"), whose values have been identified with an iterative FEM procedure. The proposed approach was applied to two different tyres (420/85 R24 and 460/85 R34), each one inflated at two different pressures (1.0 bar and 1.6 bar). Young's modulus was appreciated to be highly variable with the inflation pressure "p" of the tyres. Furthermore, the response surface methodology was applied to find two mathematical regression models, useful for studying the variations of the tyre footprint dimensions according to the type of tyre. This simple approach can be applied in other simulations without suffering any loss of accuracy in the description of the phenomenon.

In the last great fire of 2014 that affected Valparaíso, numerous building and structural deficiencies about slope construction were found. This issue was a significant factor in the number of homes destroyed. Then, the motivation arises to develop inexpensive retaining wall technologies, structurally validated, that can be implemented by people without greater technical knowledge. In parallel, Chile has a fleet close to 5,000,000 vehicles (INE, 2017). This means a potential replacement of 20,000,000 tires in 4 or 5 years, transforming them into an abundant and environmentally persistent volumetric residue, which accumulates especially in the gorges of Valparaíso. In this context, and as the first objective of this research, we identify the opportunity to contain landfills with recycled tire structures. In the present work, a vision about the state of international, national and local art about retaining wall with tires is shown and examples are presented. Then, exploratory proposals are developed, which finally settle in a definitive proposal of a retaining wall with mechanically stabilized tires. This proposal was submitted to structural calculation according to current engineering criteria, to lastly recommend it as a valid option for containing a horizontal plane with satisfactory building standards. Resumen En el último gran incendio que afectó a Valparaíso el año 2014 quedaron al descubierto muchas deficiencias, tanto estructurales como constructivas, sobre la edificación en pendiente, factores que fueron determinantes en la cantidad de viviendas destruidas. De ahí surgió la motivación para desarrollar tecnologías económicas para los muros de contención, que fueran estructuralmente válidas y pudieran ser implementadas por personas sin mayores conocimientos técnicos. Por otra parte, el año 2015, Chile contaba con una flota de unos 5.000.000 vehículos (INE, 2017). Esto significa que existe un potencial de 20 millones de neumáticos de desecho acumulables en un periodo de entre 4 a 5 años, volumen que se transforma en un residuo abundante y persistente para el medio ambiente, y que se acumula principalmente en las quebradas entre los cerros de Valparaíso. En este contexto identificamos como principal objetivo de esta investigación, la oportunidad de contener los rellenos de tierra con estructuras construidas con neumáticos de desecho. Este trabajo presenta una visión del estado internacional, nacional y local de los muros de contención construidos con neumáticos y algunos ejemplos. Se desarrollaron algunas propuestas exploratorias que derivaron finalmente en la definitiva: un muro de contención construido con neumáticos estabilizados mecánicamente. Esta propuesta se sometió al cálculo estructural de acuerdo a los criterios ingeneriles vigentes, para finalmente recomendarla como una opción válida de retener un plano horizontal bajo estándares constructivos satisfactorios. Palabras clave: Muro de contención, neumáticos, tierra estabilizada mecánicamente (TEM), construcción artesanal

The paper presents results of tire/road noise and rolling resistance measurements performed on stone-matrix asphalt (SMA) that contains rubberized asphalt developed and produced by the company in Poland. Bituminous binder was modified with polymer and additive of crumb rubber. First observations of asphalt mixture with the new kind of modified bitumen used on the field section are presented. Rolling resistance of passenger car tires was measured by test trailer R 2 Mk.2. Tire/road noise was measured by Tiresonic Mk.4 trailer using Close Proximity Method. Measurements were performed for 50 and 80 km/h and results obtained on test and reference sections covered with conventional SMA 11 were compared.

Zbadano możliwość otrzymania adsorbentów w procesie karbonizacji i aktywacji
odpadu stałego powstającego w czasie pirolizy zużytych opon samochodowych. Proces
aktywacji parą wodną prowadzono w temperaturach 750900°C w czasie 12 h.
Określono też przydatność tych sorbentów do usuwania różnego rodzaju zanieczyszczeń
z roztworów wodnych. Strukturę porowatą sorbentów określono przy użyciu
sorpcji azotu. Wykazano, że karbonizacja i aktywacja parą wodną powoduje rozwinięcie
objętości porów badanych materiałów do ponad 1,1 cm3/g i powierzchni do
około 600 m2/g. Stwierdzono, że otrzymane sorbenty wykazują wysoką skuteczność
w usuwaniu z roztworów wodnych benzenu, p-chlorofenolu, błękitu metylenowego
i czerwieni Kongo. Produkty aktywacji karbonizatów i pirolizatu z opon wykazują
podobną skuteczność oczyszczania roztworu benzenu i roztworów zawierających
barwniki jak handlowe węgle aktywne (np. Norit).
SŁOWA KLUCZOWE: zużyte opony, karbonizacja, aktywacja parą wodną, adsorbenty,
właściwości, struktura porowata, oczyszczanie wody