https://annesley.wordpress.com/burlap-crete-explained/
http://www.homeownershub.com/garden/ot-petrified-hessian-burlap-89540-.htm
There isn’t much i can add to these articles . its quick and cheap to put up,
make two walls with this material and fill the gap with stone / rock or sand to make it stop bullets . – or just use it for quick water proof structures that are light in weight .
CivilizationsEnd.com 