22 DEPARTMENT BULLETIN 12 16, U. S. DEPT. OF AGRICULTURE 
6. When check determinations are desired, the wash water shall be evapo- 
rated to dryness, the residue weighed, and the percentage calculated from the 
formula : 
_, . ... , . Weight of residue ^-.^ 
Percentage of silt, loam, clay, etc.= Qriginal dry wflght X 100 
U 5 cm. 
|/.0C/77— t^—J 
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iS 
€fQirnd Glass 
Stopper-'' 
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-ill 
— 4 s 
Hi 
K dec g 
> Capacity «3 
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13. METHOD OF TEST 
FOR APPARENT SPE- 
CIFIC GRAVITY OF 
SAND, STONE, AND 
SLAG SCREENINGS, 
AND OTHER FINE 
NONBITUMINOUS 
HIGHWAY MATE- 
RIALS 
(A. S. T. M. standard method U), 
serial designation D -55-25, ex- 
cept as indicated. (See p. 1) 
LE CHATELIER TEST 
1. The determination of spe- 
cific gravity shall be made 
with a standardized Le Chate- 
lier apparatus which conforms 
to the requirements illustrated 
in Figure 7. This apparatus 
is standardized by the United 
States Bureau of Standards. 
Kerosene or water may be used 
in making this determination. 
2. (a) The flask shall be' 
filled with either of these 
liquids to a point on the stem 
between zero and 1 cubic 
centimeter and a reading 
taken. From 50 to 64 grams 
(depending upon its approxi- 
mate specific gravity and to 
bring the reading on the 
scale) of sand or other fine 
nonbituminous highway mate- 
rial of the same temperature 
as the liquid shall be slowly 
introduced, taking care that 
the material does not adhere 
to the inside of the flask above 
the liquid and to free the ma- 
terial from air by rolling the 
flask in an inclined position. 
After all material is intro- 
duced the level of the liquid in 
the graduated stem shall be 
read, and the difference be- 
tween readings is the volume 
displaced by the known weight 
of the material. 
(&) The specific gravity shall then be calculated from the formula: 
„ .„ ., Weight of material (grams) 
Specific gravity=— — : -. : ; — — — ,. — — 
Displaced volume (cubic centimeters) 
(c) The flask, during the operation, shall be kept immersed in water in 
order to avoid variations in the temperature of the liquid in the flask, which 
shall not exceed 0.5° C. The results of repeated tests should agree within 0.01. 
Note. — This method is not accurate when sand containing a relatively large proportion 
of absorptive grains is tested. 
Have two o.lcc 
Graduations extend 
above I and 
below Mark ■ 
Capacity 
CfBulk 
opprox. 
SSOcc 
±. 
Fig. 
-Le Chatelier apparatus 
