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

Materials ◽  
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.

Cofiring Tire-Derived Fuel With Coal

2002 ◽  
Author(s):  
N. Stanley Harding
Keyword(s):  
Energy Source ◽  
Calorific Value ◽  
The United States ◽  
Present Material ◽  
Scrap Tires ◽  
Significant Interest ◽  
Fuel Characteristics ◽  
Fluidized Bed Boilers ◽  
Material Preparation ◽  
The U.S

Tires provide a resource of significant interest to many utilities. Tires—and tire-derived fuel (TDF)—have a high calorific value along with other favorable fuel characteristics. At the same time they present material preparation and handling issues for fuel users. For environmental reasons, they are more difficult and costly to dispose of in landfills. In 1990, only 25 million tires or 11% of the annually generated scrap tires in the U.S. were utilized (recycled, retreaded, and burned for energy). In 1994, this number increased to 138 million tires or 55% of the annually generated scrap tires with the largest increase due to tires used for energy (101 million tires). With an estimated number between 1–3 billion tires in stockpiles throughout the United States, this potential energy source is enormous. This paper will review several commercial demonstrations of tire-derived fuel cofired with coal in industrial and utility furnaces. Included will be discussions on fuel characteristics, preparation and handling of the tire-derived fuel, methods of utilization of the cofired fuel including appropriate combustion systems (e.g., cyclone boilers, stokers, fluidized bed boilers) and environmental results of the cofiring demonstrations.

scholarly journals Performance Analysis of Asphalt Mixtures Modified with Ground Tire Rubber Modifiers and Recycled Materials

2019 ◽  
Vol 11 (6) ◽  
pp. 1792 ◽  
Author(s):  
Punyaslok Rath ◽  
Joshua Love ◽  
William Buttlar ◽  
Henrique Reis
Keyword(s):  
Compact Tension ◽  
Asphalt Mixtures ◽  
Asphalt Pavements ◽  
Tire Rubber ◽  
Ground Tire Rubber ◽  
Reclaimed Asphalt ◽  
Dry Process ◽  
Polymer Hybrid ◽  
And Performance ◽  
Wheel Tracking

The usage of Ground Tire Rubber (GTR) in asphalt pavements has gained renewed interest due to its potential sustainability, economic, and performance benefits. This study focuses on asphalt mixtures designed with three different rubber modifier products including (1) a terminal-blend GTR, (2) a dry-process, chemically processed rubber product, and (3) a terminal-blend rubber-polymer hybrid product. The modifications were incorporated into Illinois Tollway’s approved Stone Matrix Asphalt (SMA) designs using (1) a base binder (PG 58-28), (2) a softer binder (PG 46-34), and (3) a softer binder with higher recycled content. Disk-shaped Compact Tension (DC(T)) test, Hamburg Wheel Tracking Test (HWTT) and Acoustic Emission (AE) tests were performed to characterize the mixtures. The fracture energy for most mixtures met the stringent criteria of 690 J/m2 and the rut depths measured were less than 6 mm at 20,000 wheel passes. A Hamburg-DC(T) plot suggests that higher amounts of RAP/RAS (RAP: Reclaimed Asphalt Pavement; RAS: Reusable Asphalt Shingles) can be successfully used if a suitably soft base binder is employed.

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

1998 ◽  
Vol 1638 (1) ◽  
pp. 134-140 ◽  
Author(s):  
Randy C. West ◽  
Gale C. Page ◽  
John G. Veilleux ◽  
Bouzid Choubane
Keyword(s):  
Tire Rubber ◽  
Ground Tire Rubber ◽  
Grinding Processes ◽  
Surface Areas ◽  
Grinding Method ◽  
Asphalt Rubber ◽  
Ground Rubber ◽  
Wet Ground ◽  
And Storage ◽  
Storage 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.

scholarly journals Preliminary Studies to Use Textile Fibers Obtained from Recycled Tires to Reinforce Asphalt Mixtures

2018 ◽  
Vol 7 (2) ◽  
pp. 14-30
Author(s):  
Jorge C. Pais ◽  
António Ferreira ◽  
Caio Santos ◽  
Paulo Pereira ◽  
Davide Lo Presti
Keyword(s):  
Asphalt Mixture ◽  
Tensile Tests ◽  
Crumb Rubber ◽  
Asphalt Mixtures ◽  
Asphalt Pavements ◽  
Valuable Resource ◽  
Scrap Tires ◽  
Textile Fibers ◽  
Asphalt Rubber ◽  
Indirect Tensile

Abstract The use of crumb rubber in the modification of asphalt has occurred because of the problems related to disposal of scrap tires. However, the use of scrap tires in asphalt pavements, known as asphalt rubber pavements, can minimize environmental impacts and maximize conservation of natural resources. The textile fibers from recycled tires are typically disposed of in landfills or used in energetic valorization, but similar to other fibers, they can be used as a valuable resource in the reinforcement of engineering materials such as asphalt mixtures. Thus, this work aims at studying the use of textile fibers recycled from ground tires in the reinforcement of conventional asphalt mixtures. The application of textile fibers from ground tires was evaluated through laboratory tests on specimens extracted from slabs produced in the laboratory. Indirect tensile tests were performed on a series of nine asphalt mixtures with different fiber and asphalt contents and compared with a conventional mixture. The results obtained from a 50/70 pen asphalt were used to define three asphalt mixture configurations to be used with 35/50 pen asphalt. The results indicate that the textile fibers recycled from used tires can be a valuable resource in the reinforcement of asphalt mixtures.

An American Language

2018 ◽  
Author(s):  
Rosina Lozano
Keyword(s):  
United States ◽  
National Policy ◽  
The United States ◽  
Spanish Language ◽  
Spanish Speakers ◽  
Language Recognition ◽  
Political Language ◽  
Political Issue ◽  
History Of ◽  
The U.S

An American Language is a political history of the Spanish language in the United States. The nation has always been multilingual and the Spanish language in particular has remained as an important political issue into the present. After the U.S.-Mexican War, the Spanish language became a language of politics as Spanish speakers in the U.S. Southwest used it to build territorial and state governments. In the twentieth century, Spanish became a political language where speakers and those opposed to its use clashed over what Spanish's presence in the United States meant. This book recovers this story by using evidence that includes Spanish language newspapers, letters, state and territorial session laws, and federal archives to profile the struggle and resilience of Spanish speakers who advocated for their language rights as U.S. citizens. Comparing Spanish as a language of politics and as a political language across the Southwest and noncontiguous territories provides an opportunity to measure shifts in allegiance to the nation and exposes differing forms of nationalism. Language concessions and continued use of Spanish is a measure of power. Official language recognition by federal or state officials validates Spanish speakers' claims to US citizenship. The long history of policies relating to language in the United States provides a way to measure how U.S. visions of itself have shifted due to continuous migration from Latin America. Spanish-speaking U.S. citizens are crucial arbiters of Spanish language politics and their successes have broader implications on national policy and our understanding of Americans.

Horror and Death: Rethinking Coco's Border Politics

2020 ◽  
Vol 73 (4) ◽  
pp. 41-49
Author(s):  
Orquidea Morales
Keyword(s):  
The United States ◽  
Horror Film ◽  
Walt Disney Company ◽  
Life And Death ◽  
Walt Disney ◽  
Day Of The Dead ◽  
Animated Film ◽  
Border Politics ◽  
The Dead ◽  
The U.S

In 2013, the Walt Disney Company submitted an application to trademark “Día de los muertos” (Day of the Dead) as they prepared to launch a holiday themed movie. Almost immediately after this became public Disney faced such strong criticism and backlash they withdrew their petition. By October of 2017 Disney/Pixar released the animated film Coco. Audiences in Mexico and the U.S. praised it's accurate and authentic representation of the celebration of Day of the Dead. In this essay, I argue that despite its generic framing, Coco mobilizes many elements of horror in its account of Miguel's trespassing into the forbidden space of the dead and his transformation into a liminal figure, both dead and alive. Specifically, with its horror so deftly deployed through tropes and images of borders, whether between life and death or the United States and Mexico, Coco falls within a new genre, the border horror film.

Palestine Unbound

2018 ◽  
Vol 47 (3) ◽  
pp. 130-134
Keyword(s):  
United States ◽  
Human Rights ◽  
Task Force ◽  
The United States ◽  
Donald Trump ◽  
Tel Aviv ◽  
The Us ◽  
Intention To Move ◽  
Arab Israeli Conflict ◽  
The U.S

This section, updated regularly on the blog Palestine Square, covers popular conversations related to the Palestinians and the Arab-Israeli conflict during the quarter 16 November 2017 to 15 February 2018: #JerusalemIstheCapitalofPalestine went viral after U.S. president Donald Trump recognized Jerusalem as the capital of Israel and announced his intention to move the U.S. embassy there from Tel Aviv. The arrest of Palestinian teenager Ahed Tamimi for slapping an Israeli soldier also prompted a viral campaign under the hashtag #FreeAhed. A smaller campaign protested the exclusion of Palestinian human rights from the agenda of the annual Creating Change conference organized by the US-based National LGBTQ Task Force in Washington. And, UNRWA publicized its emergency funding appeal, following the decision of the United States to slash funding to the organization, with the hashtag #DignityIsPriceless.

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