Fluff Factor

1935Ford,

(In my experience, the words "neat" and "demolished" rarely go together! )

I believe that the answer would be greatly dependent upon the mean size (diameter) of the crushed concrete.

Even fairly uniform "chunks" of concrete would likely have about 50% void spaces, so your 1.5 "Fluff Factor" is probably a little low...

What factor would you use if not 1.5 %

Probably > 1.75