Asphalt for Recycling and Energy Reduction

Authored by asphaltpavement.org and submitted by methsor

Asphalt for Recycling and Energy Reduction

Asphalt pavements are America’s most recycled product. According to the U.S. Environmental Protection Agency and the Federal Highway Administration, about 80 million tons of asphalt pavement is reclaimed each year, and nearly 100 percent of that total is recycled.

Reclaimed asphalt pavement (RAP) can be recycled into pavement that is as high, or even higher, in quality as pavements made of all-virgin materials. And, the same material can be recycled again and again; it never loses its value. The asphalt cement — the glue that holds the pavement together — retains its ability to function as glue or cement, so that it is reused for its original purpose. The aggregates (rocks, sand, and gravel) in the original pavement are also conserved. Many pavements that are more than 20 years old are actually worth more than they were when originally constructed.

It is estimated that recycling of asphalt pavements saves the American taxpayer more than $2.5 billion per year. It also saves thousands of acre-feet of landfill space each year.

Materials from other industries are routinely recycled into asphalt pavements instead of going into landfills. Some of the most common are rubber from used tires, asphalt roofing shingles, and steel and blast furnace slags.

Asphalt plants also recycle the fine mineral particles that are generated in the process of producing asphalt pavement material. This routine recycling of co-generated material helps to conserve natural resources.

Pookiebear47 on May 2nd, 2019 at 01:44 UTC »

I’m an engineer in this industry. There is a slight catch to reusing RAP over and over again. Only a certain percentage can be used in an asphalt plant during production because it can drastically reduce efficiency and let off a lot of smoke. Typically additives are introduced in the mix to help rejuvenate recycled pavement, allow it to bind better to the virgin material, and to ensure that you don’t damage the useful carbon content. Plants also can use recycled roof shingles along with recovered pavement.

The coolest part about RAP is that it’s basically free for the plant operators. Depending on how the company works they can be simultaneously removing roads, transporting RAP back, crush it down, and put it into production for the road they are replacing.

I have only heard of one plant, located in Japan, that can make asphalt using 100% RAP. It only makes small quantities at a time though.

butcher99 on May 2nd, 2019 at 00:34 UTC »

I imagine they are in use in other countries as well, but in Canada we have a machine that travels at 2 mph that grinds off the old pavement heats it up, mixes it with a minimum amount of new pavement and lays it all back down like new.

PopeliusJones on May 1st, 2019 at 22:46 UTC »

Even just straight road millings can be used to create very serviceable roads if you're not super concerned about ride quality and you just want to avoid dirt or gravel drives on properties that see mild traffic