On the Damping Properties of Modified Ground Rubber Tires

Large amounts of used rubber tires are discarded annually. A long time is needed for them to degrade naturally. This poses two major problems: environmental pollution and wastage of valuable rubber. On the other hand, with the harm of vibration and noise widely recognized, desires to control them intensify. As an important means of vibration control, viscoelastic damping technology has advanced greatly. The need for cheap and high quality viscoelastic damping materials increases rapidly. This paper made a trial to use ground rubber tire (GRT) recovered from old tires to make damping materials. The GRT is treated specially first. Then it was pressed into slabs and vulcanized. Finally, the product was cut into test samples. An Oberst beam was used to determine the loss factor βand storage modulus E. Results show that the damping materials exhibit good damping α-bility.

Effect of the Substitution of Sand by Rubber of Waste Tires on the Mechanical Properties of Hydraulic Concrete and Exposure to Gamma Radiation

For a long time and until now, rubber is the most used material for the manufacture of tires for motor vehicles. Unfortunately, once the tire meets its life cycle, the remaining rubber cannot be recycled, so the tires are discarded in collection centers and often in clandestine dumps. This represents a serious environmental problem because, in one case, these waste tires become breeding grounds for insects and wildlife that is harmful to humans. In the second case, the tires are burned, releasing highly damaging gases into the atmosphere. On the other hand, concrete is worldwide the construction material par excellence. It is basically composed of cement, gravel and sand. Mixing these three components in different proportions, their mechanical strength in compression can be increased. However, due to its fragile nature, concrete, once a crack is formed, it rapidly advances by fragmenting the material and producing its rapid collapse. In the present work, in order contribute to the care of the environment as well as to modify the fracture mode of the concrete, rubber particles obtained from waste tires were used as sand substitute in hydraulic concrete. In addition, rubber modified samples concrete were lately exposed to 70 kGy of gamma radiation in order to study the effects of this radiation on the mechanical deformation of concrete. The results showed a decrease in the mechanical properties of the concrete with rubber particles with respect to the traditional concrete itself. However, such decreases were offset by the fact that samples with rubber addition do not collapses as fast as the free rubber samples. The acquired data pave the way for research with great benefits, such as the use of recycled tires in concrete for its fracture mode modification in a beneficial way, as well as a possible decrease in the cost of concrete.

Workability and Durability of Concrete Incorporating Waste Tire Rubber:A Review

Environmental problems caused by waste tires are becoming increasingly prominent.There is an urgent need to find a green way to dispose of waste tires,and scholars have made considerable efforts in this regard.In the construction industry,rubber extracted from waste tires can be added to concrete to alleviate environmental problems to a certain extent.As a new building material,rubber concrete has superior properties compared to ordinary concrete and has been widely used in many fields.Numerous studies have been conducted worldwide to investigate the effect of waste tire rubber on the performance of concrete.It has been reported that the addition of waste tire rubber has a significant influence on the performance of concrete.Workability influences the hardened performance of rubber concrete,especially the durability.Based on the current research results,the workability and durability of concrete manufactured with waste tire rubber,including water absorption and permeability,carbonation resistance,chloride ion permeability resistance,and freeze-thaw resistance,are summarized in this paper.It is concluded that the addition of waste tires has a negative effect on the workability of concrete.In terms of durability,concrete exhibits better chloride ion penetration resistance and frost resistance,with a higher water absorption rate,and lower anti-permeability and carbonation resistance owing to the addition of waste tire rubber.

Determination of the Sound Absorption Capacity of Hydraulic Concrete Mixtures Added with Waste Tire Rubber

There are different types of pollutants that are harmful to the environment, including smog, chemicals that are dumped into rivers, scrap tires, etc. The latter have the particularity that it is not possible to recycle them to manufacture new tires. In the present work, hydraulic concrete plates added with waste tire rubber were manufactured to modify their sound absorption capacity. It was found that the rubber additions produce changes in the density of the material and in the sound absorption capacity. When the material is exposed to high-frequency sounds that correspond to high-pitched sounds, its absorption capacity increases. On the contrary, when the test frequency is low, that is, bass sounds, the sound absorption capacity decreases. The results obtained in this work suggest that the proposed mixtures are suitable for the possible manufacture of acoustic insulating shields.

Analysis of Static Temperature Field of Vehicle's Solid Rubber Tire

Aim To analyse the static temperature field ofthe solid rubber tire(SRT).Methods The mechanical and thermal FE models were developed and analyzed respectively with the FE software ANSYS.Results The maximum temperature becomes higher with the higher with the higher velocity of tire and scales down slightly with the higher convection coefficients.The mixed models are reasonable.Conclusion The study on static temperature field is important and reasonable.It gives the fundament for life analysis of SRT.

Performance of sand and shredded rubber tire mixture as a natural base isolator for earthquake protection

The performance of a well-designed layer of sand, and composites like layer of sand mixed with shredded rubber tire (RSM) as low cost base isolators, is studied in shake table tests in the laboratory. The building foundation is modeled by a 200 mm by 200 mm and 40 mm thick rigid plexi-glass block. The block is placed in the middle of a 1m by 1m tank filled with sand. The selected base isolator is placed between the block and the sand foundation. Accelerometers are placed on top of the footing and foundation sand layer. The displacement of the footing is also measured by LVDT. The whole setup is mounted on a shake table and subjected to sinusoidal motions with varying amplitude and frequency. Sand is found to be effective only at very high amplitude (> 0.65 g) of motions. The performance of a composite consisting of sand and 50% shredded rubber tire placed under the footing is found to be most promising as a low-cost effective base isolator.

Effect of Rubber Particle Modifi cation on Properties of Rubberized Concrete

To improve the combination of cement matrix and waste tire rubber particles in concrete, the rubber particles were treated with acrylic acid（ACA） and polyethylene glycol（PEG） for grafting hydrophilic groups on their surfaces. The X-Ray photoelectron spectroscopy（XPS） and surface contact angle were used to characterize the hydrophilicity and surface functional group of rubber particles. The effect of rubber particle modifi cation on fresh/hardened properties of rubberized concrete was studied. The experimental results show that the contact angle between rubber particle surface and water decreases when rubber particle is modifi ed. Compared with the unmodifi ed rubberized concrete（RC）, the unit weight of modifi ed rubberized concrete（MRC） changes slightly. However, the slump, air-entrainment, compressive strength, flexural strength, and impact performance of MRC are obviously improved. Under good condition of slump, the water-cement ratio of the MRC can be reduced from 0.4 to 0.38. And the compressive strength and fl exural strength of the MRC（10% rubber particle content） can be increased by 25.9% and 26.4%, respectively.

Modified graphite filled natural rubber composites with good thermal conductivity

The rubber composites with good thermal conductivity contribute to heat dissipation of tires. Graphite filled natural rubber composites were developed in this study to provide good thermal conductivity. Graphite was coated with polyacrylate polymerized by monomers including methyl methacrylate, n-butyl acrylate and acrylic acid. The ratios between a filler and acrylate polymerization emulsion and those between monomers were varied. Eight types of surface modification formulas were experimentally investigated. Modification formula can affect coating results and composite properties greatly. The best coating type was achieved by a ratio of1:1 between methyl methacrylate and n-butyl acrylate. The coating of graphite was thermally stable in a running tire. Filled with modified graphite, the tire thermal conductivity reached up to 0.517–0.569 W·m-1·K-1. In addition, the mechanical performance was improved with increased crosslink density, extended scorch time and short vulcanization time.

In-situ reactive compatibilization of HDPE/GTR blends by dicumyl peroxide and phenolic resin without catalyst

In-situ reactive compatibilization of high-density polyethylene （HDPE）/ground tire rubber （GTR） blends by dicumyl peroxide （DCP） and HY-2045 - a kind of thermoplastic phenolic resin without catalyst was investigated by studying the mor-phology, stress and strain behavior, dynamic mechanical properties and crystallization performance of the blends. Scanning e-lectron microscopy （SEM） results show that there are a lot of fibrous materials distributing in the interface, which connects the dispersed phase with the matrix and obtains better interfacial strength for prominent mechanical properties. The addition of compatibilizers results in the decrease of crystallinity of the blends and the disappearance of an obvious yield phenomenon, which was proved by the differential scanning calorimeter （DSC） test and X-ray diffraction （XRD） characterization Although the crystallinity of the blends decreases,the tensile strength and tensile strain of the blends significantly increases, especially for the HDPE/GTR/DCP/HY-2045 blends, which is possibly attributed to the good compatibility of the blends owing to the in-situ interface crosslinking. In addition, it is found that the compatibilizing HDPE/GTR blends shows a higher tan^ peak temperature and a broaden transition peak for GTR phase.

Measurement of stiffness and damping coefficient of rubber tractor tires using dynamic cleat test based on point contact model

The ride vibration of a tractor is affected mostly by the stiffness and damping coefficient of the seat suspension,cabin suspension,cabin rubber mounts,and rubber tires.However,in the case of rubber tractor tires,the stiffnesses and damping coefficients have not been researched adequately thus far,and it is not simple to measure these characteristics.In this study,a method for measuring and analyzing the stiffnesses and damping coefficients of rubber tractor tires,which were the input parameters for the tractor ride vibration simulation,was proposed.The cleat test,proposed in this study,did not require separate and complicated test equipment,unlike the conventional methods.The test was conducted simply by measuring acceleration under the driving conditions of the vehicle without detaching tires from the vehicle body or setting up additional test equipment.Based on the ground-vertical acceleration data obtained,the stiffness was calculated using the logarithmic decrement method,and the damping coefficient was calculated using least squares exponential curve fitting.The result of the cleat test indicated that the front tires had stiffnesses of 486.08-570.69 kN/m and damping coefficients of 4.02-4.52 kN·s/m;the rear tires had stiffnesses of 409.42-483.79 kN/m and damping coefficients of 2.21-2.67 kN·s/m.During the test,40 mm height cleats were installed on the track and the speed of the tractor was set to 7 and 10 km/h,which were the most common speeds during the operation.This study is meaningful in that it has presented a new method that improves the practicality of results,reduces cost,and simplifies the test process for measuring the stiffnesses and damping coefficients of rubber tractor tires.

Jinan Eco-Energy Brings Its Green Dream to the World

A tide of innovation is sweeping across China.For three years China has led the world in patent applications,carving a foothold in modern fields like high-speed trains,machinery exports and technical standards.

Waste Tire Rubber-based Refrigerants for Solid-state Cooling Devices

Management of discarded tires is a compelling environmental issue worldwide.Although there are several approaches developed to recycle waste tire rubbers,their application in solid-state cooling is still unexplored.Considering the high barocaloric potential verified for elastomers,the use of waste tire rubber(WTR)as a refrigerant in solid-state cooling devices is very promising.Herein,we investigated the barocaloric effects in WTR and polymer blends made of vulcanized natural rubber(VNR)and WTR,to evaluate its feasibility for solid-state cooling technologies.The adiabatic temperature changes and the isothermal entropy changes reach giant values,as well as the performance parameters,being comparable or even better than most barocaloric materials in literature.Moreover,pure WTR and WTR-based samples also present a faster thermal exchange than VNR,consisting of an additional advantage of using these discarded materials.Thus,the present findings evidence the encouraging perspectives of employing waste rubbers in solid-state cooling based on barocaloric effects,contributing to both the recycling of polymers and the sustainable energy technology field.

Dynamical mechanical behaviors of rubber-filled wood fiber composites with urea formaldehyde resin

Wood composites glued with thermosetting synthetic resins tend to show inadequate damping performance caused by the cured resinous matrix.Waste rubber maintains prominent elasticity and is feasible to be an optional modifier.To that end,composite panels of granulated tire rub-ber(GTR)powders and thermal-mechanically pulped wood fibers were fabricated in this study.Urea formaldehyde(UF)resin was applied as the bonding agent(10%based on wood/rubber total weight).Dynamical mechanical analysis(DMA)was conducted to disclose the thermo-mechanical behaviors of the rubber-filled wood fiber composites.Influence of two technical pa-rameters,i.e.,GTR powder size(0.55-1.09 mm)and addition content(10%,20%and 30%based on wood/rubber total weight),was specifically discussed.The results showed that storage modu-lus(E’)of the rubber-filled composite decreased while loss factor(tan𝛿)increased monotonously along with elevated temperature.A steady“plateau”region among 110-170°C was found where both E’and tan𝛿keep constant.Accordingly,tan𝛿showed two peak values at 103-108 and 231-233°C due to glass transition of lignin and thermal degradation of hemicellulose,respectively.Addition of rubber fillers resulted in lower bending and internal bonding strengths as well as stor-age modulus values.When the temperature was above 183°C,all the rubber-filled composites showed higher tan𝛿values than the control.The findings above fully demonstrate the improved damping performance of the UF-bonded wood fiber composites on account of rubber component.Further work is still needed to optimize the rubber/fiber interfacial bonding strength.

Review on laboratory preparation processes of polymer modified asphalt binder

Several previous studies have documented the progress in polymer modified asphalt binder with respect to materials'types and properties.However,limited or no effort was made to document findings on the laboratory preparation practices of polymer modified asphalt binder.Full and clear disclosure of asphalt blend preparation method is necessary for research continuity,reproducibility,and accurate adaptation by future studies for analogy and reliable conclusions.The laboratory preparation processes of various modified asphalt binders have been reviewed in this study.Factors affecting the optimal mixing of asphalt-polymer blends were summarized.The optimal mixing conditions associated with different asphalt modifiers were documented.Gap in the literature on the current practice for the preparation and reporting of various modified asphalt binder was discussed.Modifiers include styrene butadiene styrene(SBS),polyethylene(PE),waste tire rubber or crumb rubber(CR),ethylene vinyl acetate(EVA),sulfur,polyphosphoric acid(PPA),epoxy,polyurethane,nano-materials,etc.Currently,there is lack of modern innovative approached in the preparation of modified asphalt towards better performance.There is no clear standardized definition of term associated with asphalt binder preparation process.Given the limited and common types of polymers utilized for the modification of asphalt binder,it is possible to standardize the mixing procedure for several polymers.Doing so could ease research continuity and facilitates accurate comparison of new studies with earlier ones.