Effect of Tire Rubber Grinding Method on Asphalt-Rubber Binder Characteristics

The results of a study carried out to evaluate the effect of rubber grinding processes on the properties and characteristics of the resulting asphalt-rubber binder are presented. Several ambient and cryogenic ground tire rubber (GTR) materials were evaluated using measurements of surface areas and bulk densities. The rubber materials were then, respectively, mixed with an AC-30 asphalt; the resulting blends were tested to determine the corresponding viscosity, settlement during storage, and potential for binder draindown. The findings indicate that the asphalt-rubber binders produced with rubber from the different grinding processes have measurable differences in properties and storage characteristics that are critical to the performance of the binder in open-graded mixtures. The wet-ground rubber material had substantially lower bulk densities and larger surface areas than rubber resulting from other grinding methods. GTR materials with greater specific surface areas and more irregularly shaped particles produced asphalt-rubber binders with higher viscosities. Binders with the cryogenic ground rubber had the greatest amount of settlement and the least resistance to draindown.

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Thermo-rheological behaviour and storage stability of ground tire rubber-modified bitumens

Fuel ◽

10.1016/s0016-2361(04)00117-6 ◽

2004 ◽

Author(s):

F NAVARRO

Keyword(s):

Storage Stability ◽

Rheological Behaviour ◽

Tire Rubber ◽

Ground Tire Rubber ◽

And Storage

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Thermo-rheological behaviour and storage stability of ground tire rubber-modified bitumens

Fuel ◽

10.1016/j.fuel.2004.04.003 ◽

2004 ◽

Vol 83 (14-15) ◽

pp. 2041-2049 ◽

Cited By ~ 183

Author(s):

F.J. Navarro ◽

P. Partal ◽

F. Martı́nez-Boza ◽

C. Gallegos

Keyword(s):

Storage Stability ◽

Rheological Behaviour ◽

Tire Rubber ◽

Ground Tire Rubber ◽

And Storage

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Comparison of rheological properties and hot storage characteristics of asphalt binders modified with devulcanized ground tire rubber and other modifiers

Construction and Building Materials ◽

10.1016/j.conbuildmat.2017.07.221 ◽

2017 ◽

Vol 154 ◽

pp. 841-848 ◽

Cited By ~ 11

Author(s):

Ouming Xu ◽

Prasad Rao Rangaraju ◽

Shifeng Wang ◽

Feipeng Xiao

Keyword(s):

Rheological Properties ◽

Asphalt Binders ◽

Tire Rubber ◽

Ground Tire Rubber ◽

Storage Characteristics

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Processing, Performance Properties, and Storage Stability of Ground Tire Rubber Modified by Dicumyl Peroxide and Ethylene-Vinyl Acetate Copolymers

Polymers ◽

10.3390/polym13224014 ◽

2021 ◽

Vol 13 (22) ◽

pp. 4014

Author(s):

Paulina Wiśniewska ◽

Łukasz Zedler ◽

Krzysztof Formela

Keyword(s):

Gas Chromatography ◽

Vinyl Acetate ◽

Storage Stability ◽

Ethylene Vinyl Acetate ◽

Styrene Butadiene Rubber ◽

Dicumyl Peroxide ◽

Tire Rubber ◽

Ground Tire Rubber ◽

Performance Properties ◽

And Storage

In this paper, ground tire rubber was modified with dicumyl peroxide and a variable content (in the range of 0–15 phr) of ethylene-vinyl acetate copolymers characterized by different vinyl acetate contents (in the range of 18–39 wt.%). Modification of ground tire rubber was performed via an auto-thermal extrusion process in which heat was generated during internal shearing of the material inside the extruder barrel. The processing, performance properties, and storage stability of modified reclaimed ground tire rubber were evaluated based on specific mechanical energy, infrared camera images, an oscillating disc rheometer, tensile tests, equilibrium swelling, gas chromatography combined with a flame ionization detector, and gas chromatography with mass spectrometry. It was found that the developed formulas of modified GTR allowed the preparation of materials characterized by tensile strengths in the range of 2.6–9.3 MPa and elongation at break in the range of 78–225%. Moreover, the prepared materials showed good storage stability for at least three months and satisfied processability with commercial rubbers (natural rubber, styrene-butadiene rubber).

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Ground tire rubber (GTR) surface modification using thiol-ene click reaction: Polystyrene grafting to modify a GTR/polystyrene (PS) blend

Progress in Rubber Plastics and Recycling Technology ◽

10.1177/1477760619895016 ◽

2019 ◽

Vol 36 (2) ◽

pp. 81-101

Author(s):

Huan Liang ◽

Jacob Dion Gagné ◽

Adrien Faye ◽

Denis Rodrigue ◽

Josée Brisson

Keyword(s):

Photoelectron Spectroscopy ◽

Click Reaction ◽

Processing Temperature ◽

Tire Rubber ◽

Ground Tire Rubber ◽

Aromatic Carbon ◽

X Ray ◽

Degradation Temperature ◽

And Storage ◽

Surface Changes

In this work, a thiol-ene click reaction was used to graft polystyrene (PS) chains onto the surface of ethylene propylene diene monomer-based ground tire rubber (GTR). A thiol-terminated PS (11 kg mol−1) was selected, due to its commercial availability, to modify a postconsumer GTR. The resulting PS-grafted GTR (GTR- g-PS) particles were analyzed via Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) to detect surface changes on treated samples. An increase in aliphatic and aromatic carbon atoms was observed by FTIR and XPS, while grafted material was observed by SEM on the GTR surface, confirming that grafting took place. Then, composites were prepared from these GTR- g-PS particles and from PS by solution evaporation, at 50 wt%. A significant increase in tensile (20%) and storage moduli (from 80% at 65°C to 510% at 95°C) was observed by dynamic mechanical thermal analysis when compared to composites prepared with untreated GTR. In addition, GTR samples showed improved thermal resistance, as attested by the shift in degradation temperature for 10% mass loss (from 400°C for GTR to 450°C for GTR- g-PS). This increases the possible range of processing temperature and service temperature (applications) for introduction of GTR in other polymer matrices.

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Technical Challenges of Utilizing Ground Tire Rubber in Asphalt Pavements in the United States

Materials ◽

10.3390/ma14164482 ◽

2021 ◽

Vol 14 (16) ◽

pp. 4482

Author(s):

Rouzbeh Ghabchi ◽

Amir Arshadi ◽

Musharraf Zaman ◽

Ferrella March

Keyword(s):

Laboratory Test ◽

The United States ◽

Asphalt Pavements ◽

Scrap Tires ◽

Tire Rubber ◽

Asphalt Mixes ◽

Ground Tire Rubber ◽

Asphalt Rubber ◽

Common Practices ◽

The U.S

At least 275 million scrap tires exist in stockpiles in the U.S. The practice of dumping scrap tires in landfills has been an environmental concern. To address this concern, many industries—and regional and national environmental protection agencies—have taken major initiatives to recycle scrap tires. One of the major uses of recycled scrap tires is in crumb rubber products, including rubberized asphalt. Rubberized asphalt is produced by blending ground tire rubber with asphalt to beneficially modify its properties for highway construction. The ground tire rubber (GTR) can be used either as part of the asphalt rubber binder (also known as asphalt rubber), seal coat, cap seal spray, joint and crack sealant or as substitute aggregate (rubber-modified asphalt concrete). Therefore, the largest single market for GTR is asphalt rubber, which consumes approximately 12 million tires, annually. Currently, several Departments of Transportation (DOTs) in the U.S. do not allow use of GTR in asphalt mixes. This is partly due to lack of information, laboratory test data and specifications or special provisions on the use of GTR in asphalt pavements. The current study was undertaken to summarize the available wealth of knowledge, identify research needs, and document the major findings of previous pertinent studies focused on GTR use in asphalt. Significant study findings—consisting of laboratory test results, field observations, and common practices—were documented, including: the use of GTR in asphalt mixes, wet and dry processes, characterization of hot mix asphalt (HMA) containing GTR and GTR performance when combined with virgin materials. In order to promote successful use of GTR, it is imperative to help DOTs develop specifications/special provisions for utilizing rubberized asphalt by collecting data, common practices and specifications utilized by other state DOTs. As a part of this effort, we conducted a survey of construction specifications used by different DOTs that currently allow the use of GTR in asphalt. Since some DOT practices are not readily available in the open literature, this survey proved to be an effective tool for gathering data on the current practices, methods and specifications associated with DOT use of GTR in asphalt pavement.

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