SPECIFICATIONS FOR NONBITUMINOUS ROAD 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 : Physical 
Properties. 
Hrenchw coehicient ol wwerl noe wleSssh tianeea eee eee 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. 
Passinom -inch sereen. not elessi thane ee eae ape ee 7 95 
ERO EA ASSIMN OF Soir CHES CIee Cyaan g  e RO 40 to 80 
That portion of the product of the crusher which, when 
; ; Coarse 
_tested by means of laboratory screens, will meet the following Stone. 
requirements: 
Passing ¢s-ineh screens mot wless) than 2s See 95 
Ado Moser aR Mer aKelay So Reed DT ACO ESS 
Retained on wMeinehs Sereen= Note less) ‘than en 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. 8. Department of Agriculture Bulletin 
SA Deo: 
2. Size, U. S. Department of Agriculture Bulletin 555, p. 382. 
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______________ pY aainken + ryt Pied REg 95 
Reviinedsones-nehsereen) not less than! 222) 520 eee 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 4 gallon per square 
yard a product meeting Specification RS-2 is to be preferred. 
