Scientists replaced 40 percent of cement with rice husk cinder, limestone crushing waste, and silica sand, giving concrete a rubber-like quality, six to nine times more crack-resistant than regular concrete. It self-seals, replaces cement with plentiful waste products, and should be cheaper to use.

[u/mvea]

https://newatlas.com/materials/rubbery-crack-resistant-cement/

[u/danielravennest]

Correct. Concrete is the single most used solid product on Earth, and about 1/6 of the mass is cement. Burning rock to make cement is done at very high temperatures, and usually by burning fossil fuels.

In theory, a solar furnace could be used, but nobody has developed an economical way to do it yet. Tests have been run with small amounts in solar furnaces, so we know it works, but not on an industrial scale.

[u/tylerhz → u/danielravennest]

Just spit-balling here, but what if we could directly power concrete making ovens with nuclear power?

[u/waelk10 → u/tylerhz]

The limestone still releases CO2 when heated (even though this would probably be way more efficient than current tech).

[u/demintheAF → u/waelk10]

That's exactly the CO2 that's captured when it cures.

[u/neinjuanone → u/demintheAF]

It only captures ~43% of what it releases during the burning process

[u/KazuyaDarklight → u/demintheAF]

Sadly only 43%, so better but not perfect. https://www.sciencedaily.com/releases/2016/11/161121130957.htm

[u/demintheAF → u/KazuyaDarklight]

Half of the CO2 is from the fire to cook it. The other half is from decomposing the limestone.

[u/samtart → u/demintheAF]

Anyone have a definitive source?

[u/demintheAF → u/samtart]

The article in the link above is a pretty good source.