The US Tire Manufacturers Association (USTMA), partnering with the University of Missouri and The Ray, an Atlanta, Georgia-headquartered non-profit proving ground for sustainable transportation technologies, published a state of knowledge report that assessed existing research on the economic, performance and environmental benefits of using ground tyre rubber (GTR) in asphalt; and is, thus, a resilient pavement solution to rebuild America’s roadways. It finds that rubber modified asphalt compared to traditional asphalt, provides cost savings over the life of the asphalt, extends pavement life, and reduces noise, CO2 emissions and tyre and road wear particles. Rubber modified asphalt also leads to lower rolling resistance, which helps improve fuel economy.
The research was peer-reviewed by a technical advisory panel of regulators, researchers and scientists that provided support, insights and feedback. The study reviewed more than 300 scholarly articles and reports and surveyed 26 state highway agencies to identify data gaps in knowledge and barriers to more widespread adoption of rubber modified asphalt nationwide.
According to Dr Bill Buttlar, Director of the Missouri Centre for Transportation Innovation and the report’s lead researcher, the research outlines why states should review and expand asphalt specifications to incorporate this rubber asphalt alternative. “We should continue to research rubber modified asphalt to better understand the complete picture of this pavement’s environmental impact and benefits, ” he said. Allie Kelly, Executive Director of The Ray said that the report demonstrates the value of upcycling tyres into higher performing roads that will help states save money over the life of the roadway and make our roads quieter. “The opportunity to scale and expand the utilization of rubber-modified asphalt across all 50 states has arrived, with Congressional action on transportation and infrastructure funding, and the publishing of this inventory of the best research and analysis of RMA, ” Kelly said.
Anne Forristall Luke, President and CEO of USTMA said that the research proves that rubber modified asphalt is a strong and viable application for advancing the sustainability and circularity of scrap tyres, adding that USTMA supports infrastructure legislation to increase opportunities for university and government research, regional innovation hubs for rubber modified asphalt, and federal procurement of rubber modified asphalt. “To help grow this market safely and responsibly,” she said.
The state of knowledge report identified data gaps that should be addressed to better inform modern pavement design software programs, including the need for additional research on the life cycle impact of rubber modified asphalt and its properties and characteristics, the researchers said.