Here is a clay block wall in a workshop I built some years back, as a sort of limited illustration for the topic as there were no timbers involved in the wall construction.

The blocks are compressed clay with a fairly corse agrigate - up to roughly 4 mm- of river sand and hemp or flax (once the fibers from the dried plant stocks are removed, this by-product is left over, lets say the shredded outsides of the stems. I made a pile the other day with my daughter when we were making rope).

The mortar is more or less the same stuff the blocks are made of - even breaking up and using the blocks themselves is ideal because as mentioned, the mortar has a certian relationship to the brick/block used and should not just be arbitraily chosen.

I understand the idea about using woodchips as a filler and I'm sure it has been done but I am sceptical about using it for this purpose. Wood chips don't seem like a very stable medium and wood shavings seem rather useless because the fibers are all shorn through. It takes me more effort to pull apart a stem of flax or even a piece of straw then it does a shaving of wood and wood chips and shavings attract moisture. So there are no structural advantages to wood and what's more they may weaken the structure. As for the insulating value of wood we all know that it is a shitty insulator whereas straw is not bad and hemp and flax are very good insulators particularly regarding sound insulation. I've just never heard of anyone who regularly works with clay and has easy access to wood chips and shavings using them in combination. For many of the same reasons I don't dispose of my wood chips and shavings by using them in the stall or chicken coop I wouldn't use them in the clay. Wood chips are better destined for smoking your ham or covering your path.