Cob Fibre

[Otherfish at aol.com]

david
re fibers
I'm not sure that anybody really knows the answer to your question
it seems as tho the viable life of fibers of any sort (when embeded in the
earth clay/silt/sand matrix)  that are kept at the stable dry condition that
an earthen wall will attain if the matrix is allowed to breathe & kept
protected from water intrusion) are very long lasting when embeded in the
earthen material.
-so mayhaps the best advice is: give it a try 
-make some samples & see what you get

one intresting concept re fiber length is the concept of development length
- an earthen matrix will be able to grip a given fiber to some measurable
extent
-if the length of the fiber is greater than the sum value of the matrix's
gripping strength versus the  value of the fibers inherent tensile strength
-then to make the fiber any longer will add no increase in strength to the
earth matrix/fiber bond of grip strength versus tension strength
not to complicated
wish there was some way to measure this
oh well

so your guess is a good as anybody's at this point
jump in
let the list know how it works out for you

cob on 
john fordice
TCCP
otherfish at aol.com