What is Recycled Asphalt?
“Asphalt pavement is America’s most recycled material. It is being recycled at a rate of 99% (NAPA, 2012).” Almost all asphalt that is removed from project sites are crushed and reused. Additionally, asphalt roof shingles are actively being used in the hot-mix process. The green movement is alive and well in the asphalt industry.
Asphalt that is pulled off site is known as Reclaimed Asphalt Pavement (RAP). RAP is introduced into new hot-mix asphalt by means of crushing the asphalt and using it in conjunction with virgin aggregate and virgin liquid asphalt. The amount of RAP that is used varies with each mix design. The amount of RAP used represents over 3 million tons (19 million barrels) of liquid asphalt each year conserved (NAPA).
In addition, Recycled Asphalt Shingles (RAS) contribute to the composition of “green asphalt”. “Asphalt shingle manufacturing plants will usually generate scrap shingle waste of between 5 – 10 percent of production, which is approximately 1.3 million tons (CRA, 2012).” In the past, shingles wound up in landfills. Now, the asphalt industry has welcomed the discarded shingles as a way to decrease cost and preserve the environment. RAS is included in mix designs much like RAP. The shingles are crushed and used in producing new hot-mix asphalt. “Use of recycled asphalt shingles increased from 702,000 tons to 1.10 million tons from 2009 to 2010, a 57 percent increase (NAPA, 2012).” The amount of liquid asphalt that is now being conserved through the use of RAS is well over 1.5 million barrels/year. This is a great indication of two industries working together to drive the green movement.
What are the cons?
Asphalt produced with recycled asphalt pavement in general performs quite well. There is some concern over the make-up of asphalt produced with RAS. It can cause pavement to age quicker than virgin asphalt as it dries out the binder that holds Hot-Mix together. This is still a newer process and pavement sections are still being evaluated for their long-term wear.
Regardless of your opinion on recycled asphalt, it is in encouraging to be part of an industry that continues to find ways to maintain a sustainable future.