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The "RAP" on Recycled Pavement


bowers research 1What?s America?s most recycled product? Is it pop cans? Glass bottles? Newspapers?


As it turns out, the number one most recycled product, according to the National Asphalt Pavement Association (NAPA), is asphalt pavement. In fact, millions of tons of worn-out road asphalt are reclaimed and recycled each year to build new roads at a lower cost and a fraction of the environmental price-tag of new materials.


Over time, roads become damaged and wear out. You?ve probably had the not-so-pleasant experience of driving down a pot-holed street that needed to be resurfaced. Quite a bumpy ride. In order to resurface a road, first it has to be stripped. For a long time, common practice was to simply dump worn-out road asphalt into landfills. Until engineers had a bright idea. If other things can be recycled, why not roads? Thus, RAP (Recycled Asphalt Pavement) was born, and it's used in most road paving and resurfacing projects that take place in the U.S. today.


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From an environmental standpoint, aside from not clogging up landfills, RAP has a number of tremendous advantages over non-recycled asphalt pavement. One of the biggest advantages is that it greatly reduces a project's petroleum requirement. Petroleum, which can be harmful to the environment when it is obtained, processed, and shipped, is one of the main ingredients used to make new asphalt. Instead, recycled RAP materials are made from pre-existing asphalt, and are removed and processed right at the construction site. This eliminates a lot of greenhouse emissions and fuel expenditures. For these and other reasons, RAP roads are more environmentally sustainable, and save millions of taxpayer dollars.



But the use of RAP has not been perfected yet. Recycled roads aren’t paved with 100% RAP. In fact, the percentage is much lower, often more like 30% according to research by the Federal Highway Administration. That's where researchers like University of Tennessee, Knoxville civil engineering Ph.D. candidate Ben Bowers come in. Bowers is conducting research on materials and construction techniques to make RAP an even stronger, more durable alternative to new materials in road maintenance and construction.


“You have whole conferences talking about how to solve this issue and committing research to this,” Bowers said.


The science of recycled materials for road work is still relatively new. As the technology continues to be improved, the use of RAP will become even more widespread, and the environmental benefits will climb. As sustainability continues to increase in importance to society, and sustainability practices continue to be reflected in engineering, transportation-related career opportunities in the field of recycled materials will be vast.


For Bowers, his career own path provided him a way to combine his interest in science with his passion for the environment and sustainability. He credits his father, as well as his high school drafting teacher, for introducing him to the transportation industry and inspiring him to pursue engineering during college, where he originally discovered the world of recycled materials. ?


“Before that, I didn’t know what engineering was,” he said. “If you told me I was going to be working on my Ph.D., I would’ve laughed.”


bowers childhoodBowers advised students interested in transportation and engineering to seek out mentors in the form of parents or teachers for assistance in pursuing their own career paths. His mentor in college was a professor that Bowers grew to know not by being the best student in class, but through struggling in the class and seeking help.


“I went to his office and started talking to him and actually found out that I had a lot in common with him,” Bowers said. “He just continued to encourage me and continued to meet with me, and he actually became my graduate adviser for my master’s degree, and wrote recommendations for me to go elsewhere to work on my Ph.D. I still talk to him today. Always try to put yourself around good folks who are encouraging, and talk to your professors or your teachers,” Bowers said.



Bowers also advised students to begin to gain college and career exposure by exploring extracurricular activities like Science Olympiad during middle school and high school. And he said students should not be afraid to try advanced courses in their favorite subjects.


“If I could do anything differently and go back, I think I would’ve started to look at different things I could’ve been involved in that maybe would’ve opened my eyes to what else is out there in terms of career options,” he said.


To find out what is out there for you in transportation, or in the field of recycled materials specifically--or for more information on the history and science of reclaimed materials in transportation--you can check out NAPA’s web page that's dedicated to RAP. You can also learn more about RAP and its impact on the environment by visiting, a website hosted by the Asphalt Education Sponsorship, or by visiting the Asphalt Pavement Alliance.

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