Australian researchers are using recycled coffee grounds to create stronger (and more sustainable) concrete. They heat the coffee grounds in the absence of oxygen to create biochar, a charcoal-like substance that can replace up to 15% of the sand used in concrete. This not only makes the concrete stronger but also reduces the amount of cement needed, which in turn reduces greenhouse gas emissions.
* 60 million tons of coffee grounds are produced worldwide each year.
* 60-70% of coffee grounds end up in landfills, where it produces methane.
* The coffee-infused concrete is up to 30% stronger than traditional concrete.
Although it can only replace 15% of the sand in concrete, that important because, believe it or not, we're running out of sand.
3:19 Most sand eroded by wind is very round and doesn't help bind the concrete together. The more useful angular sand is in short supply. And 0:19 Concrete is the second biggest raw material consumed by humans after water.
Concrete production produces huge amounts of greenhouse gases, "resulting in approximately 8% of the world's anthropogenic CO2 emissions, and about 25% of all industry carbon emissions."* https://news.asu.edu/20231017-curbing-concretes-carbon-emissions-innovations-cement-manufacturing
An enterprising teenager started a business of making sand from recycled glass.
As with coffee biochar, only up to 20% of sand can be replaced with glass before it becomes detrimental to the final concrete product.
"It was found that 20% of cement can be replaced with waste glass of 20 μm without detrimental effects on the mechanical properties. Replacements higher than 30% can cause negative impacts as insufficient amounts of CaCO3 remain to react with the silica from the glass, known as the dilution effect."
https://youtu.be/tKjIybiWYTU?si=Z-xjBqm2OzKxIhpd
A new concept places recycled plastic spheres into concrete slabs to achieve similar strength with less weight.
For a similarly sized slab, voids 6:57 decrease the shear stress capacity by 55% without having reinforcing steel around them, which can be mitigated if you 8:42 only place the voids away from areas of shear stress..
When done right, a "waffle" design of the voids can make 0:35 installation of utilities easier.
https://youtu.be/cmxXFM2kqBU?si=nVZAVSB2MjbbKJpb
Also, this company makes prefab insulated concrete panels to reduce waste and speed construction.
https://youtu.be/zv_jfTIKKv4?si=SjDAkU29koy1A6BV
The company is backed by actor Michael Keaton.
https://youtu.be/gXMG1Kz6se0?si=kKVhPq8VC-P-8C5t
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