TESTS FOR NON-BITUMINOUS 

 ROAD MATERIALS. 



1. ABRASION TEST FOR BROKEN 

 STONE. 



(A. S. T. M. Standard method, serial designation 

 D 2-08, slightly modified.) 



(1) The machine (see fig. 1) shall consist 

 of one or more hollow iron cylinders, closed 

 at one end and furnished with a tightly fit- 

 ting iron cover at the other; the cylinders to 

 be 20 cm. in diameter and 34 cm. in depth 

 inside. These cylinders are to be mounted 

 on a shaft at an angle of 30° with the axis of 

 rotation of the shaft. 



(2) The rock to be tested shall be broken 

 from large irregular pieces to as nearly uni- 

 form size as possible, and as near to 50 pieces 

 as possible shall constitute a test sample. No 

 pieces having edges or faces that have been 

 rounded by wear shall be included. The 

 total weight of rock in a test shall be within 

 10 grams of 5 kilograms. All test pieces 

 shall be washed and thoroughly dried before 

 weighing. Ten thousand revolutions, at the 

 rate of between 30 and 33 per minute, shall 

 constitute a test. *Only the percentage of 

 material worn off which will pass through a 

 0.16-cm. (^-inch) mesh sieve shall be con- 

 sidered in determining the amount of wear. 

 This shall be expressed as the percentage of 

 the 5 kilograms used in the test. 



(3) For materials having a specific gravity 

 below 2.20 the quantity used for the test 

 shall be adjusted on a volume basis, re- 

 taining the specified number and size of 

 pieces. For such materials a volume of 

 4,000 c. c. of the broken stone or broken slag 

 shall be used. 



2. ABRASION TEST FOR GRAVEL. 



(1) The aggregate shall first be screened 

 through screens having circular openings 2 

 inches, 1^ inches, 1 inch, £ inch, and \ 

 inch in diameter. The material of these 

 sizes shall be washed and dried. The fol- 

 lowing weights of the dried stone shall then 

 be taken: 1,250 grams of the size passing the 

 2-inch and retained on the l-|-inch screen, 

 1,250 grams of the size passing the 1^-inch 

 and retained on the 1-inch screen, 1,250 

 grams passing the 1-inch screen and retained 

 on the f-inch screen, 1.250 grams passing 



