Density can be measured with the standard shear cell or with a special density cell. Usualy, we start with lowest load and increase the load by next steps. For each step a consolidation time has to be chosen, in order to reach a steady state density.
The density is non-reversible. By changing the load up and down. The density has a hysteresis.
The bulk density for pressure p=0 will be found directly after filling the cell or by extrapolation of the measured points.
The density should be measured in steps according to your input but the first step always has to be done under the smallest load.
By increasing the pressure the density increases also according to an exponential curve and reaches a limit value after a certain time.
By running the test by increasing pressure and thereafter by decreasing pressure we will see that the density dos not decrease to the original value but stay higher than that. By multi-repeating the test we will reach a kind of hysteresis for density.