As far as I’m aware “aerated concrete” is the next step up in concrete tech: https://www.buildinggreen.com/news-article/autoclaved-aerated-concrete-aac-will-us

As far as I’m aware “aerated concrete” is the next step up in concrete tech: https://www.buildinggreen.com/news-article/autoclaved-aerated-concrete-aac-will-us-ever-lighten https://www.buildinggreen.com/news-article/autoclaved-aerate... It’s lighter, less energy intensive, better insulator, basically just by inserting bubbles into the structure. Widely used in Europe but not adopted by the US because lumber is cheap and we don’t have any established manufacturers.