The shrink percentage of a material is used to calculate the decrease in volume from bank to compacted state. Just as with swell having a load factor, shrink factor has an associated load factor. The load factor can be used to calculate the mass density of the material, lb/yd3 or kg m3, as it changes from bank to compacted state.
Dry Clay is listed as having a bank mass density of 3220 lb/yd3 with a shrink percentage of -10%
A shrink of -10% has a shrink factor of 0.900 and a load factor of 1.111
bank mass density of 3220 lb/yd3
shrink factor = 0.900
load factor = 1.111
The decrease in volume from bank to compacted state = 1 * 0.009 = 0.9 cubic yards
The change of mass density for one lb/yd3 from bank to compacted = 3220 * 1.111= 3577 lb/yd3
The final result, dry clay as it changes from bank to compacted, has a volume of 0.9 yd3 and a material weight of 3577 lb/yd3.
Shrink and load factors are unit less and work the same for imperial and metric measurements as long as units used are identical.
Since the shrink percentage is calculated from the bank state of the material it does not always have to be a negative % but will be smaller than the swell percentage.