Can We Make Roads Out of Recycled Plastic?

Plastics clog our ecosystems and our roads need maintenance -- could fixing one problem help solve the other? Learn how researchers are recycling plastics into useful materials in this episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:02):
Welcome to brain Stuff from How Stuff Works, Hey, brain Stuff,
Lauren Voge obamb here. A few years ago, engineer Toby
McCartney was working in southern India with a charity that
aided pickers who worked at landfill sites harvesting reusable items
and selling them. McCartney discovered that the plastic waste they
retrieved was being put into potholes and roads, dused with

(00:23):
gasoline and set a fire. When the plastic melted into
the holes and then hardened, it filled them. When McCartney
returned to Scotland, he told two of his friends about
what he had seen. As one of them, Gordon Reid, recalls,
they decided that it would work better to use plastic
waste to create a new type of materials specifically designed
for use in roads. After a year of research, they
developed a method for transforming a mix of industrial and

(00:46):
consumer plastic waste into pellets of a new material that
could replace bitumen, the oil based ceiling material that holds
asphalt together in roads. Since Reid's company Mcgreeber started operations
in April of sixteen, the companies recycled plastic road building
material has been used to build roadways in places ranging
from Australia to Dubai. Read says we've got roads on

(01:08):
every continent, and we've had interest from round about fifty
countries in the world. The company currently is having discussions
with the University in California about building a test road
to demonstrate that its plastics are compatible with standards in
the United States. According to Read, using recycled plastic for
road buildings sounds simple, but it actually requires a complex
process to create the right material. He explained, different plastics

(01:31):
do different things to bitterman. If you use the wrong mix,
it can actually make the bitterman more brittle. Mcgreeper avoids
using pet bottles and other types of plastic that are
easily recycled, and instead concentrates on types of waste plastic
that might otherwise end up buried in the ground. Read
declined to go into too much detail as so not
to reveal too much about mcgreeber's proprietary process. In addition

(01:53):
to keeping plastic out of landfills, the company says it's
plastic road materials can save about a ton in carbon
dioxide output for each town of Benemen that the plastic replaces.
The company has developed different types of road building plastic
four different environments. One variety is designed for roads in
such places as the Middle East, where more tensile strength
is needed to resist asphalts tendency to deform from heat.

(02:16):
Another is designed to be more flexible and resist the
freeze thaw cycle in colder places such as Canada or Scotland.
Read says mcgreeber's current products are capable of replacing between
six and twenty of the bitumen in roads, but Read
is hopeful that within two years improved versions will replace
as much as Read says that mcgreeber's plastic road materials

(02:37):
physically bind with betterman which prevents it from breaking loose
and getting into the environment. In the US, plastic is
already being used in road maintenance. University of Texas at
Arlington civil engineer Professor Sahodat Hussein, director of the School
Solid Waste Institute for Sustainability, has turned to recycled plastic
as a way to solve the problem of unstable soil

(02:58):
on highway slopes, which unually can cause the road surface
to fail. As well. He's developed a technology for taking
plastic from landfills and then recycling it to manufactured giant
pins that are inserted into the falling soil to stabilize it.
Causean explained via email that the recycled plastic pin quote
has been successfully tested as a laterally loaded pile in

(03:20):
different highway slope stabilization projects in the state of Texas, Iowa,
and Missouri. The Texas Department of Transportation has adopted the
recycled plastic pin as one of their approved slope stabilization methods.
It takes just three to four minutes to install each
of the pins in the ground, so an entire unstable
area can be shored up in a few days. He said.

(03:40):
Once the pin is installed into the ground, it is
less susceptible to degradation, which makes it a long lasting
solution for slope repair. Each recycled pin utilizes about five
hundred plastic soda bottles. At one of the demonstration sites,
Hussein's research group puts six hundred plastic pins into the ground,
making use of some three hundred thousand plastic models that
otherwise would have ended up in landfills. Coussine thinks that

(04:03):
the Chinese government's recent decision to ban imports of plastic
waste for recycling could create an opportunity for US entrepreneurs
to make road materials. China imported seven hundred and seventy
six thousand metric tons of plastic waste from the United
States in two six. Hussein said, I am positive more
and more roads will be constructed using recycled plastics, but

(04:25):
he does note that more work needs to be done
to develop new methods, including full scale testing and life
cycle analysis of roads containing plastic materials. Today's episode was
written by Patrick J. Kaiger and produced by Tyler Clang.
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