We did a few test bags to see if this would work for us as a building type.
We used empty hog
feed bags (woven poly) that hold 50 lbs. of feed.
When filled so they would hold their shape after tamping, these bags held 100 lbs.
A little to much for my 64 year old body when building a wall so that turned us away from using them for our house.
We are going to use them for the above ground portion of our
root cellar/ storm
shelter though, we will be able to fill them in the spot they will end up.