BULLETIN" 555, U. S. DEPARTMENT OF AGRICULTURE. 
Methods of 
lesting. 
General. 
Grading. 
Methods of 
sampling and 
grading. 
Tests of the physical properties and grading of the stone shall 
be made in accordance with the methods described or referred 
to on pages of these specifications, tests Nos. . 
Broken Stone or Sand fob Fine Aggregate. 
The fine aggregate shall be composed of sound, durable par- 
ticles of stone or sand. The particles shall be free from a coat- 
ing of clay or loam. 
The broken stone or sand for fine aggregate, when tested by 
means of laboratory screens and sieves, shall meet the following 
requirements : 
Per cent 
Passing 1/4-inch screen not less than 
Passing 1/4-inch screen and retained on 
10-mesh sieve to 
Passing 10-mesh and retained on 40-mesh 
sieve 1 to 
Passing 40-mesh and retained on 200-mesh 
sieve : to 
Passing 200-mesh sieve not more than 
Stone or sand shall be sampled for grading in accordance with 
the methods described on page , paragraphs , of 
these specifications, and tests of grading shall be made in ac- 
cordance with the method described or referred to on page 
of these specifications, test No. 
SPECIFICATION FOR COARSE AND FINE AGGREGATE FOR TOPEKA TYPE 
BITUMINOUS CONCRETE (BROKEN STONE OR SAND). 
General. 
Physical prop- 
erties. 
Grading. 
Broken Stone for Coarse Aggregate. 
The broken stone for coarse aggregate shall consist of angular 
fragments of i. i P. se .f t .. t ^. e . s ..^. llo .^^ 1 . e . : f., free from thin or elongated 
pieces, soft or disintegrated stone, dirt, or other objectionable 
matter, occurring either free or as a coating on the stone. 
The stone shall meet the following requirements : 
Per cent of wear not more than 
{or French coefficient not less than ) 
*Hardness not less than 
♦Toughness not less than 
♦Absorption not more than % 
The broken stone for coarse aggregate, when tested by means of 
laboratory screens, shall meet the following requirements: 
Per cent. 
Passing (the J^?^t?tee selected) inch screen- 100 
Passing (]^e J^^st size »ele^cted) inch screen 
and retained on (the __second largest _ size 
selected_ inch screen to 
tPassing, etc 
* Tests recommended by the conference, which it may be desirable to 
omit in some instances. 
t The number and sizes of screens may be continued as desired by the 
engineer. The last requirement should be : Passing 10-mesh sieve, not 
more than 
