According to the Royal Society of Chemistry, concrete is the most widely-used material in the world.
Over two billion metric tons of concrete are poured each year around the globe, supporting the growth of infrastructure. Unfortunately, producing concrete takes a tremendous amount of energy and resources, so it isn't very eco-friendly.
A group of Australian researchers led by Dr. Rabin Tuladhar of James Cook University are seeking to change the environmental burden of concrete production while also addressing another important ecological challenge: large amounts of plastic in the landfill.
In order to give concrete the structural support it needs to hold up roads, skyscrapers, and homes, aggregates (typically crushed rock) are added to cement, and metal reinforcement bars are added. Rather than use metal bars or mesh, Tuladhar's lab is using plastic is in order to provide the additional support.
"Using recycled plastic, we were able to get more than a 90 percent saving on CO2 emissions and fossil fuel usage compared to using the traditional steel mesh reinforcing. The recycled plastic also has obvious environmental advantages over using virgin plastic fibres," Dr. Tuladhar said in a press release.
How helpful will this new concrete really be?
Let's break down the numbers using RSC's figure of two billion metric tons of concrete poured each year, and 900 kilograms of carbon dioxide emissions per ton of standard concrete as described by the researchers.
With a 90% reduction in CO2 emissions, the recycled plastic concrete will emit only 90 kilograms of carbon dioxide per ton. That's a pretty big difference.
If all concrete was replaced with this recycled product, total carbon emissions due to concrete would be reduced from 1.8 trillion to 18 billion metric tons.
Essentially, that would be the same as taking over 375 million cars off the road for an entire year, according to the EPA. Not bad!
Beyond the implications for reducing greenhouse gases, this new concrete also reduces the amount of plastic in the landfills, which could be particularly important to wildlife.
Conventional plastic doesn't biodegrade, but it is capable of breaking into smaller pieces. As explained by PBS, when animals see the small bits of colorful plastic in their environment, they can confuse it with their prey and eat it. This can cause them to choke, but even if they are able to swallow it, they're still not out of danger.
Animals aren't able to digest the plastic, so it can accumulate in their stomachs. If an animal eats too much plastic, there isn't any room for food, and the animal starves to death. If smaller animals who are eating plastic get eaten by larger animals, the plastic merely moves up the food chain.
Which means that producing the new concrete using recycled plastics could have a pretty significant impact.
Future research is needed in order to determine the structural integrity of the new plastic, in order to determine the best possible use for this promising new material. The team also plans to find additional ways to decrease the ecological burden of this product.
Cover photo via James Cook University.