California will test a stretch of highway paved using recycled plastics

Paving roads is a dirty business. That may not come as much of a surprise, given that there is actual tar involved. Still, plenty of the materials used during the paving process aren’t necessarily very environmentally friendly, and considering the number of roads America has, it adds up to a big problem.

What if there were a way to replace some of those less-than-savory chemicals and ingredients with recycled materials that we already have way too much of anyway, like plastics? That’s what CalTrans and a company called TechniSoil are doing with a new stretch of highway outside Oroville, California.

If TechniSoil sounds familiar, it’s probably because we covered its plans to repave a busy intersection in downtown Los Angeles last year with a similarly plastic-infused asphalt material. That pilot program was successful enough to enter this new, more extensive phase.

“We’re excited about introducing a new sustainable technology and helping pave the way for utilization of recycled plastics throughout the state,” Caltrans District 3 Director Amarjeet S. Benipal said in a statement Thursday. “This process is better for the environment because it keeps plastic bottles out of landfills and helps reduce greenhouse gas emissions and reliance on fossil fuels.”

Paving contractors have been using reground asphalt as a part of the roadbed construction process for a while now. That process takes between 3 and 6 inches of road surface off with a large machine that grinds it up and mixes it with a bitumen foam. This process is great for reusing old asphalt, but it’s not durable enough to be used as the road’s surface.

For that, contractors have to bring in traditional hot-mix asphalt from a production plant and apply that over the recycled material. This adds materials, labor and transportation costs to an already expensive process, not to mention added greenhouse emissions from making and trucking the stuff to a job site.

The TechniSoil G5 binding material is different because it eliminates the hot-mix step entirely. It does this by grinding down the top 3 inches of the roadway and then mixing it with a liquid polymer binding agent that’s made predominantly of recycled plastic bottles — approximately 150,000 bottles’ worth per lane-mile. This new recycled mix is durable enough to be used as the top layer of a highway road surface and promises to last even longer than traditional hot-mix asphalt. 

“California has set ambitious goals for recycling and other environmental priorities, and meeting them requires innovative and cost-effective solutions,” California State Senator Ben Hueso said in a statement Thursday. “Using waste plastic that was otherwise destined for a landfill will not only reduce the cost of road repair and construction, but also increase the strength and durability of our roads. As a leader on environmental justice issues, California is uniquely positioned to transform the transportation industry once again by using this new technology that could revolutionize the way we look at recycled plastic.”

So, right, this is probably a lot more than you thought you needed to know about road paving. Still, the benefits to the state of California in terms of reduced greenhouse gas emissions from not using hot-mix asphalt and having to truck it to job sites from facilities miles away as well as money saved through reduced need for maintenance could end up being a pretty big deal. We’re also interested in seeing other, colder states test the TechniSoil process out and see if it could work in places like Michigan, which also has notoriously bad roads.