Questions about raised beds

i plan to build some raised beds using interlocking vinyl sheet piles. Can I use material from a rough cut sawmill as a base fill instead of logs. It will be from hardwood. The saw blades produce vary course shreadded wood instead of sawdust. Some people use it as mulch around trees and bushed.  

Unless they are big chucks of wood, then no.. it will compress and compact as sawdust, not allowing air and water to circulate.

i use coarse sawdust from a firewood business. if it becomes compacted, fluff the surface w/ a leaf rake occasionally. works good. been doing this for over 7 yrs. now.