Yes. But it depends on what you're constructing. I'm from Baltimore where you cant dig a hole without hitting oyster shells, so I've asked this myself. Many years ago I was told that they used to burn the shells to make lime for concrete. Tabby concrete They're also used in landscaping.

I imagine a bit of brainstorming would find some interesting uses, but without a compelling reason to innovate... I did find this: Chemical-mechanical characteristics of crushed oyster-shell.