SAMPLING AND TESTING HIGHWAY MATERIALS. 



9 



the side of the cylinder 6 inches from the bottom. The spout is inclined at an angle 

 of 2° with the horizontal and is 2\ inches long. A notch is filed across its lower end, 

 as shown, to stop the drip from the displaced water. To determine the specific 

 gravity, the dried and cooled sample shall be weighed to the nearest 0.5 gram and 

 immersed in water for 24 hours. The pieces shall then be surface-dried individually 

 with a towel, the sample reweighed and immediately placed in the cylinder, which 

 has been previously filled to overflowing with water at room temperature. 



(2) The weight of water displaced by the sample shall be used to calculate its 

 apparent specific gravity. The difference between the original weight of the sample 

 and its weight after 24 hours shall be used to determine the absorption. 



£1 Galvanized 



Iron ^ p r5 "D. 



Note: Notch is filed across 

 lower end of spout j/g|" (2°) 

 to prevent drip.zz=-.. r 



F>~* 



<o 



JLX 



CO 



Tl 



XThree lugs soldered on) 

 bottom lymmetrically. 



Fig. 7. — Vessel used in making specific-gravity and absorption tests. 



6. TESTS FOR APPARENT SPECIFIC GRAVITY OF SAND, STONE, OR 

 SLAG SCREENINGS AND OTHER FINE NON-BITUMINOUS HIGHWAY 

 MATERIALS. 



(A. S. T. M. Standard Methods, Serial Designation: D 55-19.) 



(1) The following tests, "Le Chatelier" and "Jackson," are equally suited for use 

 in determining the apparent specific gravity of sand, stone, and slag screenings and 

 other fine non-bituminous highway materials and may be considered as alternates. 



I. LE CHATELIER TEST. 



(2) The determination of specific gravity shall be made with a standardized Le 

 Chatelier apparatus which conforms to the requirements illustrated in figure 8. This 

 apparatus is standardized by the United States Bureau of Standards. Kerosene free 

 from water, or benzine not lighter than 62° Baume, shall be used in making this 

 determination. 



