Rubberized Asphalt Today: A Changing Legacy

Highway and road engineers have added recycled tire rubber, to modify and improve asphalt for more than 40 years. Two important events in October showcased the growing domestic and global reach of rubberized asphalt and took a step in ending “legacy thinking” about rubber modified asphalt pavements.

Ending legacy thinking is about breaking out of the comfort zone. It’s about learning. And it’s about adapting to new technologies and new ways of doing things.

A glance through the presentations at the Recycled Rubber Products Technology Conference held in Las Vegas and the 6th Rubber Modified Asphalt Conference in Phoenix, AZ provides a roundup of the ways rubberized asphalt is enhancing performance, saving money, improving safety, reducing noise and making its mark as a green technology in a mounting number of U.S. states, European countries and cities, Russia, Poland and the Far East.

In “10 Changes in 10 Years” Michael Blumenthal, Vice President, Rubber Manufacturers Association (RMA) summarizes some of the new concepts and approaches that are helping end legacy thinking about rubber in asphalt. These include warm mix technology, terminal blends using rubber and performance grade rubber modified asphalt.

In 2003, ten states were using rubber modified asphalt (RMA). In 2013, 25 states are using RMA. In 2003, rubberized asphalt was mostly used in the U.S. In 2013, it’s used worldwide.

Rubberized asphalt is changing in other ways. States are beginning to look at asphalt products that have rubber and PG grading of asphalt rubber and rubberized asphalt, George Way, Chair of the Rubberized Asphalt Foundation (RAF) said. Also, the types of rubberized asphalt are changing, he said. There’s asphalt rubber, a product that technically has more than 15 percent recycled tire rubber (RTR); rubberized asphalt, a premium grade product with 8-12 percent RTR; rubberized asphalt hybrid with 7 percent RTR and 2 percent polymer; and rubberized asphalt super activated material, a dry granulate 30 mesh activated rubber “ready to go” into asphalt.

How we talk about using rubber in asphalt is changing too, Blumenthal said. “Field blend” and “terminal blend” don’t really describe the products any more. Terminal blend products can be “field blended” and field blend products can be produced at an asphalt terminal. More descriptive terms are being used to identify products and clarify their handling. For example, rubberized asphalt products may can be offered as “particulate” binders and “non-particulate” binders available on demand or bulk storage.

The rubberized asphalt industry now has access to two high quality, highly respected organizations. The Rubberized Asphalt Foundation , founded last year, looks to progressive science, sustainable engineering and practical applications to raise awareness and broaden the use of rubberized asphalt. The long-established Rubber Pavements Association (RPA), Tempe, AZ is targeting savings, not only in dollars but in natural resources and reduced CO2 emissions, in its new messaging to the industry and the driving public.

Both groups are key to driving interaction between industry, departments of transportation and state agencies to continue education and dialogue about new and proven technologies and ways of using rubber modified asphalts.

And, the Federal Highway Administration (FHWA) is looking to these groups for things like material usage tools, construction guidelines, technical support for updating rubber modified best practices, and support for the development of technical and other information, FHWA Recycling Coordinator Victor Gallivan said.

© Scrap Tire News, December 2013