SPECIFICATIONS FOR NONBITUMINOUS EOAD MATERIALS. 



That portion of the product of the crusher which, when tested by Bottom Course 

 means of laboratory screens, will meet the following requirements : Stone. 



Per cent. 



Passing 3-inch screen, not less than 95 



Total passing 2J-inch screen 25 to 75 



Retained on 2-inch screen, not less than 85 



Tests of the physical properties of the rock and of the sizes of broken- Xe^stiiig! ** 

 stone products shall be made in accordance with the following methods : 



1. French coefficient of wear, U. S. Department of Agriculture Bulletin 



347, p. 5. 



2. Size, U. S. Department of Agriculture Bulletin 555, p. 32. 



This specification is intended to cover stone to be used in tlie 

 construction of a water-bound broken-stone base, and a t)itumi- 

 nous brolien-stone wearing course constructed by the penetration 

 metliod. If the base is not to be water bound, the use of granite, 

 gneiss, sandstone, or quartzite may be allowed, provided the ma- 

 terial otherwise meets the specifications. Practically the entire 

 output of an ordinary portable crushing outfit will be utilized If 

 a bottom course filled with screenings is constructed 5 inches 

 thick and a top course from 2^ to 3 inches thick. The chips should 

 be used to fill the surface voids in the top course after the first 

 application of bituminous material has been made and also as a 

 cover for the second application or seal coat. Such roads may be 

 maintained with surface treatments of bituminous material, cov- 

 ered with material conforming to Specification RS-1 or IlS-2. 



SPECIFICATION RB— 2. 



Broken Stone for Bituminous Macadam Wearing Course. 



The broken stone shall consist of angular fragments of rock, excluding fi„_»j.„i 

 schist, shale, and slate, 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 requirement : Physical 



French coefficient of wear, not less than 7 Properties, 



That portion of the product of the crusher which, when tested by means (jjjjpg 

 of laboratory screens, will meet the following requirements : 



Per cent. 



Passing 1-inch screen, not less than 95 



Retained on i-inch screen, not less than 85 



That portion of the product of the crusher which, when tested by means Coarse 

 of laboratory screens, will meet the following requirements : Stone. 



Per cent. 



Passing 2-inch screen, not less than 95 



Total passing IJ-inch screen 25 to 75 



Retained on 1-inch screen, not less than 85 



Tests of the physical properties of the rock and of the sizes of broken Methods of 

 stone products shall be made in accordance with the following methods : Testing. 



1. French coefficient of wear, U. S. Department of Agriculture Bulletin 



347, p. 5. 



2. Size, U. S. Department of Agriculture Bulletin 555, p. 32. 



This specification covers stone to be used in the construction of 

 a bituminous broken-stone wearing course in which the bituminous 

 material is applied by the penetration method. The maximum size 



