28 BULLETIN 407, U. S. DEPARTMENT OF AGEICULTUBE. 



the plant was still slightly warm from the refining process. The 

 distance from the plant to the near end of the section was about 12 

 miles. 



Experiment No. 5. — ^Repined Coal Tar, Hot Application, Similar to Experi- 

 ment No. 1, ON ROCKVILLE PlJEE. 



Location: Station 226+20 to station 295+00. 



Length: 5,880 feet. 



Total area: 9,800 square yards. 



Date of application: September 13, 14, 15, and 16. 



Temperature of tar: 180° F. 



Table 29. — Analysis of refined coal tar used on experiment No. 5. 



Specific gravity, 25°/25° C 1. 181 



Float test at 32° C. (time) 1M5'' 



Free carbon (insoluble in CSg), per cent 9. 39 



_. .,, . Percent Percent 



Distillation: by volume, by weight. 



Water 0.0 0.0 



Fii-st Ught oils (to 110° C) .0 



Second Ught oils (110° to 170° C.) .0 



Heavy oils (170° to 270° C.) 13. 5 11. 4 



Heavy oils (270° to 315° C.) 13. 2 IL 3 



Pitch residue 73. 3 77. 8 



Total 100. 100. 5 



The surface of section No. 5 was also in excellent condition, and 

 the experiment was conducted similarly to experiments Nos. 3 and 

 4. The bitumen was prepared in a local plant and was hauled to 

 the work in the distributors ready for apph cation. The haul from 

 the plant to the near end of the section was about 11 miles. 



The cost data given in Table 30 are based upon the following unit 

 prices for labor and materials. 



Foreman, per 8-hour day $4. 00 



Distributor operator, per 8-hour day 2. 50 



Roller operator, per 8-hour day 3. 00 



Motor-truck driver, per 8-hour day 2. 50 



Teams, per 8-hour day 4. 00 



Laborers, per 8-hour day 1. 60-2. 00 



Gravel on siding, per ton 1. 65 



Asphaltic petroleum on siding, per gallon ^.05 



Residual asphaltic petroleum on siding, per gallon •*. 07| 



Coal-tar preparation on siding, per gallon ■'. 09J 



Refined water-gas tar at plant, per gallon '. 08^ 



Refined coal tar at plant, per gallon '-08 



1 Estimated. 



