r/science • u/mvea Professor | Medicine • Nov 03 '19
Chemistry 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.
https://newatlas.com/materials/rubbery-crack-resistant-cement/
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u/Ehcksit Nov 03 '19
Roman concrete worked by being used in extremely large and massive objects that prevented wind and other torsion forces from having much effect. Concrete is extremely resistant to compression, so making it huge and heavy is fine.
But we want useful structures. We want a bridge you can also go under, and concrete alone won't work for that. We reinforce the concrete against torsion with steel rebar, but steel rusts and expands and cracks the concrete from the inside.
You can't build a skyscraper with Roman concrete. You'll just get a solid column with no internal space. Modern engineering isn't about making things as strong and durable as possible. It's about making things use as few materials with as much usable space as possible and still strong enough.