Tabby concrete, made with lime from burnt oyster shells and a shell aggregate, was refined by enslaved people in the southeastern US before Portland cement came along. Fascinating article: placesjournal.org/article/tabb...

Tabby Concrete: An Eroding Architectural History

Linked through Black and Indigenous heritage, tabby concrete is a cross-generational, transnational building material that architectural historians must preserve.

Today we would call this climate-resilient