Environment

How to make concrete stronger and more environmentally friendly with irradiated water bottles

How to make concrete stronger ...
Adding a small amount of irradiated plastic to concrete can make it up to 20 percent stronger
Adding a small amount of irradiated plastic to concrete can make it up to 20 percent stronger
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Adding a small amount of irradiated plastic to concrete can make it up to 20 percent stronger
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Adding a small amount of irradiated plastic to concrete can make it up to 20 percent stronger

Concrete has shaped the modern world. Other than water, it is the most widely used material on the planet so it's unsurprising that scientists are constantly working to make it safer, stronger and more environmentally friendly. A team of MIT students have discovered a clever technique that uses irradiated plastic bottles to make a new concrete up to 20 percent stronger than regular concrete.

The students were initially exploring ways to reduce the global carbon footprint of the concrete industry, which accounts for 4.5 percent of the world's man-made carbon dioxide emissions. They also wondered if there was a way to recycle the huge amount of plastic that goes into landfill every year and use it to improve concrete production.

Other research into incorporating plastics into cement has been unsuccessful, with the plastic weakening the concrete, but the team wondered if there was a way to treat the plastic so it could ultimately strengthen concrete?

The research revealed that exposing the plastic to gamma radiation actually made it stronger. The irradiated plastic was then ground into a power and mixed with cement. The subsequent concrete was up to 20 percent stronger than concrete made without the irradiated plastic.

"We have observed that within the parameters of our test program, the higher the irradiated dose, the higher the strength of concrete, so further research is needed to tailor the mixture and optimize the process with irradiation for the most effective results," says Kunal Kupwade-Patil, one of the research scientists working on the project.

Examining the plastic-infused concrete using backscattered electron microscopy and X-ray microtomography the team discovered that crystallinity of the concrete was fundamentally altered to become denser with the addition of the irradiated plastic. It's also worth noting that the final product doesn't hold any radioactivity.

"There's no residual radioactivity from this type of irradiation," explains Michael Short, assistant professor in MIT's Department of Nuclear Science and Engineering. "If you stuck something in a reactor and irradiated it with neutrons, it would come out radioactive. But gamma rays are a different kind of radiation that, under most circumstances, leave no trace of radiation."

Despite the irradiated plastic only consisting of 1.5 percent of the concrete mix, the researchers suggest that on a global scale this would still have a significant impact on carbon emissions, as well as reducing plastic landfill and creating a stronger concrete product. There is no mention of how much energy (or carbon emissions) go into recycling and irradiating the plastic so we do remain slightly skeptical of the overall emission reduction resulting from the process.

"Concrete produces about 4.5 percent of the world's carbon dioxide emissions," says Short. "Take out 1.5 percent of that, and you're already talking about 0.0675 percent of the world's carbon dioxide emissions. That's a huge amount of greenhouse gases in one fell swoop."

Source: MIT

12 comments
rude.dawg
Irradiated by gamma rays, heh? Can it be called HULKcrete?
Dan Marsh
Strictly speaking, this is downcycling rather than recycling. Recycling would be making new plastic bottles from used plastic bottles. Also, how would this concrete be disposed of when the building is eventually demolished? Regular concrete can be recycled by crushing and grading it in to aggregates. Can that be done with this "plastic concrete"?
notarichman
does it make the concrete harder or softer? i'm thinking of using it for roads. any place that gets worn by abrasion.
Douglas Bennett Rogers
This could be valuable for nuclear waste storage.
DaleBarclay
No reason it could not be recycled. The plastic is ground to a powder.
BanisterJH
I wonder how adding the ground irradiated plastic compares to adding fly ash, silica fume or polyvinyl alcohol and whether it will additionally strengthen concrete that has also been strengthened using those other additions.
pmshah
I know of gamma rays being used in England for substantially extending shelf life of fresh produce. Just wonder why it is not more widely used and a lot of food is allowed to rot !
Don Duncan
What concrete was used? Grancrete brags it is 500% stronger. And what is the cost of irradiation? I don't support any eco-measures that need subsidy. Doing so is asking to be scammed by politicians/business. See: Alternative energy.
CoachFerg
Plants love carbon dioxide. Water vapor is the real greenhouse gas. Let's do something about that.
slarmas
https://newatlas.com/cement-overlooked-carbon-sink/46569/ Would be funny if this caused the new found carbon sink mechanism to fail and make concrete once again a net producer of carbon rather than the new found carbon sink that it is now considered to be.