Humboldt H-3383L Humboldt Specific Gravity Flask (Phunque Flask) - Manual (Page 5)

Step 10 Aggressively shake, roll and agitate the flask for a period of three
minutes so that all of the air is allowed to escape. (A plug must be
placed into the neck of the coarse aggregate flask to prevent loss of
water during the shaking and agitation to prevent water loss during
this step.)
Step 11 Allow the flask to remain undisturbed for two minutes.
Step 12 Obtain and record the reading at 5 minutes.
Step 13 Repeat steps 9 through 11 to obtain additional readings at 10
minutes, 30 minutes, 60 minutes, 2 hours, 4 hours and 25 hours
(plus or minus 1 hour), making sure to agitate all of the air out of the
sample, as described in Step 10, and allowing the flask to settle for
at least two minutes before taking each reading.
Note: Remember to eliminate all released air during the soak period from
the flask before taking the final reading. Make sure that the flask
has been completely shaken and agitated, and then allowed to
rest undisturbed so all of the air has escaped. Take as much time as
required to completely eliminate all of the air
Step 14 Add the base reading obtained from calibrating the flask to each of
the individual readings.
Step 15 Plot the readings on semi-log paper with the x-axis being "time" on
the logarithmic scale.
Step 16 Calculate absorption, conventional absorption, saturated bulk
specific gravity (BSGssd) and dry bulk specific gravity (BSGd) with
the equations detailed below. If necessary, apparent dry specific
gravity (ASGd) can be calculated as well, but this is rarely used for
construction aggregate applications.
Calculating absorption:
Absorption, percent = [(Vi – Vfinal) / Wd] x 100
Where:
Vi = Initial Reading (The calibrated water volume at 0 plus the initial reading),
ml
Vfinal = Final Reading (The calibrated water volume at 0 plus the final reading)
ml
Wd = Original dry weight of sample, g
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