ASTM D 2419, AASHTO T 176
Conventionally particle size distribution analysis is carried out using
pipette and hydrometer methods. Whereas in hydrometer method it
is possible to determine particle sizes in the range 75microns, the
method involves computation and it is time consuming. The pipette
method can be used for determining only the percentage of specific
sizes less than 0.02, 0.006 and 0.002mm as a percentage of total soil
sample. The plummet balance method to determine sub sieve
particle size for the entire range is very rapid and only manipulation
of height of the balance, so that plummet sinks to the right depth is
required. The percentage of soil in suspension is directly indicated by
a pointer over a graduated scale. A vertical rod is mounted on a
sturdy base having leveling screws. A pointer with steel pivots turns
is jewel bearing an moves over a graduated scale. Scale graduations
are market 0-100% x 2% To the other end of the pointer a plummet
is hanged. Rack and pinion arrangement is provided on the vertical
rod for adjusting the height. Supplied with a chart showing
relationship between "K" and temperature of suspension of soils of
varying specific gravity from 2.4 to 2.8 to help in solving stroke's
equation. Supplied complete with one Perspex plummet one
measuring jar and one rider weight for zero adjustment and rider
weight for adjusting the pointer to 100%.