Interesting addition to the WISE website at CAT, explaining about the rammed earth wall there.
At 7.2 metres, the circular walls of the Sheppard Theatre are the highest rammed earth walls in the UK. To make rammed earth walls, loose, moist subsoil is compacted in thin layers between shuttering or formwork. Mechanical compaction forces clay molecules to bond with the aggregate (a physical rather than a chemical bond), giving the wall its strength. Particle size and grading, moisture content, and clay content are all critical to the performance of the finished wall.
Although the build had quite a few problems, I’m hopeful that the project will serve to inspire more rammed earth building in the UK