58 BULLETIN 940, U. S. DEPARTMENT OF AGRICULTURE. 



the final aggregate and the original amount taken gives the amount of bitumen ex- 

 tracted which is subject to correction of the amount, of ash determined from the wash- 

 ings. Ash correction to he made as given under A. 



34. DETERMINATION OF WATER IN BITUMINOUS MATERIALS. 



The apparatus consists of a copper still, G by 31 inches; a ring burner to fit the still; 

 connecting tube: condenser trough; condenser tube: separatory funnel; and a ther- 

 mometer, 0°-250° C. 



In the case of coal-tar material, 50 c. c. of coal tar naphtha or light oil shall be 

 measured into a 250 c. c. graduated cylinder, and 200 c. c. of the material, to be tested 

 shall be added. In the case of petroleum products, petroleum naphtha may be used. 

 The contents shall be transferred to the copper still and the cylinder shall be washed 

 with 100 to 150 c. c. more of naphtha, and the washings added to the contents of the 

 still. The lid and clamp shall be attached, using a paper gasket, and the apparatus 

 set up as shown in figure 27. The condenser trough should be filled with water. 

 Heat should be applied by means of the ring burner and distillation, continued, until 

 the vapor temperature has reached 205° C. (401° F.). The distillate shall be collected 

 in the separatory funnel, in which 15 to 20 c. c. of benzol or naphtha have been pre- 

 ■ApproxJ&cm. 



■Appjvx. 2.85cm. 



Appro** 

 /.25cm 



Capacity of Bulb 

 250 to 290 cc. 



Fig. 32.— Retort for distillation test. 



viously placed. This effects a clean separation of the water and oil. The reading 

 shall be made after twirling the funnel and allowing to settle for a few minutes. The 

 percentage shall be figured by volume. 



When fresh supplies of naphtha or light oil are obtained they shall be tested to deter- 

 mine freedom from water. 



It is recommended that further investigation be made on this method by using a 

 water-saturated solution of naphtha. This criticism has been made on the method 

 due to the fact that naphtha possibly possesses an affinity for water. 



35. TESTS OF PREMOLDED JOINT FILLERS. 



The bituminous material before manufacture into the premolded joint fillers should 

 be subjected to the tests as for poured expansion joint fillers. 



36. TESTS FOR EMULSIONS. 



The essential tests on emulsions are per cent of water and quality of bitumen. 

 The percentage of water may be obtained by the methods of water determinations 

 in test No. 34 without the addition of naphtha or benzol. The emulsion can be broken 



