SPECIFICATIONS FOR NONBITUMHSTOUS EOAD MATERIALS. 



SPECIFICATION RW-2. 



Broken Stone for Water-'bound Base. 



The broken stone shall consist of angular fragments of rock, excluding General. 

 granite, gneiss, sandstone, quartzite, schist, shale, and slate, of uniform 

 quality throughout, free from thin or elongated pieces, soft or disin- 

 tegrated stone, dirt, or other objectionable matter. 



The stone shall meet the following requirement : ProBorties 



French coefficient of wear, not less than 5 



That portion of the product of the crusher, including the dust of frac- Screenings, 

 ture, which, when tested by means of laboratory screens, will, meet the 

 following requirements : 



Per cent. 



Passing 1-inch screen, not less than 95 



Total passing J-inch screen 40 to 80 



That portion of the product of the crusher which, when 

 tested by means of laboratory screens, will meet the following Stone. 



requirements : 



Passing 3-inch screen, not less than 95 



Total passing 2-Jnch 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 provides primarily for stone to be used in the 

 construction of water-bound base upon which some higher type 

 of wearing course will be placed, preferably after the base has 

 been finally compacted by traffic. For the softer grades of rock 

 it may also serve for both foundation and wearing courses, pro- 

 vided the thickness of each is not less than 4 Inches. In case 

 the broken-stone base is not to be water bound, granite, gneiss, 

 sandstone, and quartzite may be allowed. 



SPECIFICATION RS-1. 



Coarse Broken Stone for Bituminous Surface Treatment. 

 The broken stone shall consist of angular fragments of clean, hard. General. 

 tough, durable rock of uniform quality throughout, free from soft or 

 disintegrated stone, dirt, or other objectionable matter. 



It shall be that product of the crusher, which when tested by means Size. 



of laboratory screens, will meet the following requirements : 



Per cent. 



Passing 1-inch screen, not less than 95 



Retained on J-inch screen, not less than 85 



Tests of the size of broken stone shall be made in accordance with the Method of 



following method : Testing. 



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



This specification provides for a broken-stone product which 

 may be used as cover for a bituminous material applied hot to a 

 road surface. For this purpose it should be evenly spread at the 

 rate of 1 cubic yard to every 50 to 75 square yards of treated 

 road surface, depending upon the amount of bituminous material 

 which has been applied per square yard. Under traffic, prefer- 

 ably preceded by rolling, it is expected to produce, in combination 

 with the bituminous material, a wearing mat or carpet. When the 

 treatment of bituminous material is less than ^ gallon per square 

 yard a product meeting Specification RS-2 is to be preferred. 



