54 



BULLETIN 407, U. S. DEPARTMENT OF AGEICULTURE. 



Tables 54 and 55 show comparative cost data to date for the various 

 experiments included in this project. 



Table 54. — Surface maintenance costs of 1913 experiments on Rockville Pike, Mont- 

 gomery County, Md., to December 31, 1915. 



Ex- 

 peri- 

 ment 

 No. 



Bituminous material. 



Date 

 com- 

 pleted. 





Total 

 cost 1 

 per 



Surface 2 

 main- 

 tenance 



Total 

 cost of 

 surface 



Surface 

 main- 



Length. 



square 



yard 



prior to 



Jan. 1, 



1915. 



per 

 square 



yard 

 during 



1915. 



per 

 square 

 yard to 

 Dec. 31, 



1915. 



tenance 



per mile 



per year 



1915. 



1913. 

 Sept. 22 



Feet. 

 9,060 



Cents. 

 12.34 



Cents. 

 15.36 



S27. 70 



§1,129.90 



Sept. 24 



4,425 



9.55 



9.34 



18.89 



137.81 



Sept. 30 



7,400 



9.05 



11.37 



20.42 



401.20 



Oct. 15 

 Nov. 21 



7,100 

 6,775 



11.28 

 11.30 



3.93 

 4.02 



15.21 

 15.32 



170. 20 

 141. 78 



Nov. 26 



6,325 



11.71 



15.82 



27.53 



1,200.48 



Dec. 5 



6,689 



10.03 



10.38 



20.41 



828.84 



Total 

 main- 

 tenance 

 per mile 



for 

 1 year. 



Refined coal tar (hot). . . . 



Refined water-gas tar 

 (cold) 



Asphaltic petroleum 

 (cold) 



Residual asphaltic pe- 

 troleum (hot) 



do 



Water-gas tar prepara- 

 tion (hot) 



Asphaltic petroleum 

 (cold) , 



§1,486.49 



202.22 



529.25 



276. 73 

 226.68 



1,270.93 



894.24 



Average for trap and gravel. 



2 To December 31, 1915. 



Table 55. — Materials and cost data for surface retreatments in 1915 on Rockville Pike, 



1913 project. 



Reo- 



Bituminous material. 



Area 



of 



section. 



Quantity of material per 

 square yard. 



Cost per square 

 yard (cents). 



tion 

 No. 



Bitum- 

 inous 

 material. 



Gravel. 



Sand. 



Bitum- 

 inous 

 material. 



Gravel. 



1 



Refined coal tar, hot application. .... 



Asphalticpetroleum,coldapplication 

 Water-gas tar preparation, hot appli- 



Sq.ft. 

 15,000 

 7,400 



10,542 

 11, 148 



CfalloTis. 



0.425 



.165 



.474 

 .204 



Cu. yds. 

 0.014 



Cu. yd. 



0.038 

 .014 



0.043 



•^ 



0.016 





6 



.018 





7 





.011 



.022 















Bituminous material. 



Cost per square yard (cents). 



Sec- 

 tion 

 No. 



Sand. 



Cleaning 

 surface. 



Applymg 

 bitu- 

 minous 

 material. 



Applying 

 sand or 

 gravel. 



Super- 

 vision. 



Total. 



1 







0.003 

 .002 



0.007 

 .008 



0.015 

 .005 



0.003 

 .005 



0.109 



3 



6 



Asphaltic petroleum, cold application 

 Water-gas tar preparation, not appli- 

 cation 



0.036 



.070 

 1.111 



7 



Asphaltic petroleum 



.023 



.001 



.006 



-.004 



.002 



.058 









1 Work done by contract. 



