Technical Challenges of Utilizing Ground Tire Rubber in Asphalt Pavements in the United States
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 tire...
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doaj-f93f0d9aff854bf1b42a434e904a5e622021-08-26T14:00:43ZengMDPI AGMaterials1996-19442021-08-01144482448210.3390/ma14164482Technical Challenges of Utilizing Ground Tire Rubber in Asphalt Pavements in the United StatesRouzbeh Ghabchi0Amir Arshadi1Musharraf Zaman2Ferrella March3Department of Civil and Environmental Engineering, South Dakota State University, Brookings, SD 57007, USAProject Manager, AECOM, Chelmsford, MA 01824, USASchool of Civil Engineering and Environmental Science, University of Oklahoma, Norman, OK 73019, USAUsed Tire Recycling Program, Oklahoma Department of Environmental Quality, Oklahoma City, OK 73102, USAAt 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.https://www.mdpi.com/1996-1944/14/16/4482hot mix asphalt (HMA)ground tire rubber (GTR)wet processdry processrubberized asphaltasphalt mix performance |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Rouzbeh Ghabchi Amir Arshadi Musharraf Zaman Ferrella March |
spellingShingle |
Rouzbeh Ghabchi Amir Arshadi Musharraf Zaman Ferrella March Technical Challenges of Utilizing Ground Tire Rubber in Asphalt Pavements in the United States Materials hot mix asphalt (HMA) ground tire rubber (GTR) wet process dry process rubberized asphalt asphalt mix performance |
author_facet |
Rouzbeh Ghabchi Amir Arshadi Musharraf Zaman Ferrella March |
author_sort |
Rouzbeh Ghabchi |
title |
Technical Challenges of Utilizing Ground Tire Rubber in Asphalt Pavements in the United States |
title_short |
Technical Challenges of Utilizing Ground Tire Rubber in Asphalt Pavements in the United States |
title_full |
Technical Challenges of Utilizing Ground Tire Rubber in Asphalt Pavements in the United States |
title_fullStr |
Technical Challenges of Utilizing Ground Tire Rubber in Asphalt Pavements in the United States |
title_full_unstemmed |
Technical Challenges of Utilizing Ground Tire Rubber in Asphalt Pavements in the United States |
title_sort |
technical challenges of utilizing ground tire rubber in asphalt pavements in the united states |
publisher |
MDPI AG |
series |
Materials |
issn |
1996-1944 |
publishDate |
2021-08-01 |
description |
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. |
topic |
hot mix asphalt (HMA) ground tire rubber (GTR) wet process dry process rubberized asphalt asphalt mix performance |
url |
https://www.mdpi.com/1996-1944/14/16/4482 |
work_keys_str_mv |
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