That’s the problem with looking for strength rather than resilience in a building material. Every traditional building method is a system where all the parts are doing certain, multiple jobs for each other. As you change to a new material, it takes time to develop the system of all the detailing that needs to be done so that new material gets to deliver what it has promised without creating problems.
around ~38:00 of “Building a Cob Style Rocket Mass Heater” from Permies.com
You want it to be plumb… Masonry is the art of stacking everything so gravity becomes your glue. …doesn’t matter what arch you’re making, what bridge you’re making, it’s held together by gravity…all those stresses are going down to the ground, not out to the side, …”