BULLETIN 555, U. S. DEPARTMENT OF AGRICULTURE. 



Physical prop- 

 erties. 



Chips or No. 

 . stone. 



Top course or 

 No. stone. 



Bottom coarse 

 or No. stone. 



Mel hod of sam- 

 pling. 



Methods of 

 testing. 



The stone shall meet the following requirements : 



Per cent of wear not more than 



(or French coefficient not less than .) 



♦Toughness not less than 



♦Hardness not less than 



*Absorption not more than % 



That portion of the product of the crusher which, when tested 

 by means of laboratory screens, will meet the following require- 

 ments : 



Per cent. 



Passing inch screen 100 



Total passing inch screen to 



Retained on inch screen 100 



That portion of the product of the crusher which, when tested 

 by means of laboratory screens, will meet the following require- 

 ments : 



Per cent. 



Passing inch screen 100 



Total passing inch screen to 



Retained on inch screen 100 



That portion of the product of the crusher which, when tested 

 by means of laboratory screens, will meet the following require- 

 ments : 



Per cent. 



Passing inch screen 100 



Total passing inch screen to 



Retained on inch screen 100 



Stone shall be sampled for quality and size in accordance with 



the method described on page , paragraphs , of these 



specifications. 



Tests of the physical properties and sizes of the stone shall be 

 made in accordance with the methods described or referred to on 

 pages of these specifications, tests Nos. 



SPECIFICATION FOR BROKEN STONE AGGREGATE FOR LARGE AGGREGATE 

 BITUMINOUS CONCRETE. 



General. 



Physical prop- 

 erties. 



Grading. 



The broken stone aggregate shall consist of angular fragments of 

 ..J^^}jJ^iL3^}?^M^j of uniform quality throughout, 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 aggregate, when tested by means of laboratory 

 screens, shall meet the following requirements : 



* Tests recommended by the conference^ which it may be desirable to 

 emit in some instances. 



