What is the difference between Filling Capacity, Uncompacted Output and Compacted Output?
When the mixer is filled to its DRY FILLING CAPACITY, as the stone, sand and cement mix, the air spaces between stone chunks get filled with sand, and the air spaces around the sand grains get filled with cement. The density goes from about 100 lb/cu. ft. to 150 as it is mixed. Even the spaces around the cement powder get filled – with water. The whole volume reduces by 20% or more as a zero slump mix is made. But this zero slump mix still has lots of air spaces in it. If discharged in this state, you get an UNCOMPACTED YIELD of 20% less than the mixer capacity. When the mix is vibrated in the mould or form, all this extra air is expelled and it compacts by a further 15 to 20% to give the COMPACTED YIELD, which is 2/3 of the dry filling capacity.
