That's news to me too. I thought that once concrete sets, its chemical composition has changed. It can't be ground down to make into concrete again.
its chemical composition has changed. It can't be ground down to make into concrete again.Concrete has aggregates (rock, sand etc.) mixed with cement to give it strength. Also, cement isn't manufactured it has to be mined...you know like gold and coal. IOW, you can't grow or manufacture more cement.
Concrete (the end product of cement) is ground up and used for road base and maybe an aggregate with cement to make low grade concrete.
By using their definition of "sustainable" it could be argued that plastic is sustainable.