BULLETIN 555, U. S. DEPARTMENT OP AGRICULTURE. 



Methods of 

 testing. 



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. '. . 



Beoken Stone oe Sand foe Fine Aggeegate. 



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 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. 



Beoken Stone foe Coaese Aggeegate. 



The broken stone for coarse aggregate shall consist of angular 

 fragments of (insert types aUowabie)_, 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 (^.A^sest size selected) inch screen. 100 



Passing (^j^rgest size L^lected) inch screen 

 and retained on ltke_second largest size 



selected_ inch screen to 



f Passing, 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 



