Description and Identification of Soils (Visual-Manual Procedure) - Soil Properties: Testing, Measurement, and Evaluation - page 37

with the sand-size particles and the fines. Mentally compare the
number of sacks to estimate the percentage of plus No. 4 sieve size
and minus No. 4 sieve size present. The percentages of sand and
fines in the minus sieve size No. 4 material can then be estimated
from the wash test.

(3) Wash Test (for relative percentages of sand and fines) —Select
and moisten enough minus No. 4 sieve size material to form a 1-in.
(25-mm) cube of soil. Cut the cube in half, set one-half to the side,
and place the other half in a small dish. Wash and decant the fines
out of the material in the dish until the wash water is clear and
then compare the two samples and estimate the percentage of sand
and fines. Remember that the percentage is based on weight, not
volume. However, the volume comparison will provide a reasonable
indication of grain size percentages.

(3.1) While washing, it may be necessary to break down lumps of
fines with the finger to get the correct percentages.

REFERENCE

[1] ASTM , 2007 Annual Book of ASTM Standards, West Conshohocken, PA,

2007. Copyright, American Society for Testing and Materials, 100 Barr
Harbor Drive, West Conshohocken, PA 19428-2959. Reprinted with
permission.