[urikaduri]

I've read that adding a little bit of graphene can make concrete much stronger, lighter and easy to shape, so would allow for thinner objects.

[bluGill]

There are a lot of additives to concrete - the industry is large and has put a lot of money into research over the decades. You can read many many books on the pros and cons of different options.

[bookofjoe]

Translucent concrete: https://www.allplan.com/blog/translucent-concrete/