DUST PEEVEITTION AN^D ROAD PRESERVATION", 1915. 



17 



215 + 28 to 219 + 00 it was necessary to remove entirely the old mac- 

 adam base to correct the profile, and a new base was built of "l^- 

 inch" granite spread to a loose depth of 6 inches and rolled with a 

 10-ton roUer until compacted, without the addition of any binder. 



The surface was exactly similar to that in experiment No. 16, 

 except that the stone was granite, with physical properties and 

 mechanical analyses as shown in Tables 4 and 6, respectively. The 

 mechanical analyses of the chips used are shown in Table No. 7. The 

 percentage of the weight of asphalt to the total weight of asphalt and 

 stone was 6.73. The mixing was done near station 215 + 00. 



Experiment No. 20. — Bituminous Macadam (Mixing Method). 

 WITH Fluxed Native Asphalt A. 



Gkanite 



Location: Station 225+10 to station 235+50. 



Total length: 1,040 feet. 



Total area: 1,866.7 square yards. 



The base of this experiment was an old trap-rock water-bound 

 macadam road, which was scarified and reshaped. Considerable 

 extra stone C'lJ-inch" granite) was added from stations 229 + 00 

 to 234 + 00 to supplement weak places ia the old macadam. 



The surface was laid exactly as in experiment No. 19, except that 

 fluxed native asphalt of the analysis shown in Table 8 was used 

 instead of oil-asphalt. 



SUMMARY OF COST DATA FOR ENTIRE PROJECT. 



The cost data for the experiments described above are presented in 

 the tables which follow, Nos. 13 to 23. 



Table 13. — Cost data for subgrade, 

 [Subgrade, stations -(1+61) to 235+50.] 



Items. 



Clearing 



and 

 grubbiag. 



Excava- 

 tion. 



Sliaping. 



Scarifying 



and 

 reshaping. 



Rolling. 



Subgrade, 

 complete. 



Qnantity 



Acres. 

 5.0000 



Cubic yards. 

 28,575 



Square yds. 

 45,835 



Square yds. 

 11,378 



Square yds. 

 67, 213 



Square yds. 

 1 42 111 







Labor 



$125.57 



S8,237.71 

 287.05 



$.3,a35.83 



$348.17 

 6.80 



$72. 74 

 30.55 



$11,820.02 

 324.40 



Materials 











Total 



125.57 



8,524.76 



3,035.83 



354.97 



103. 29 



12 144.42 







Unit cost 



Acre. 

 $25. 114 

 .22 



Cubic yard. 



$0. 298.3 



15. 24 



Square yard. 



$0.0662 

 5.42 



Square yard. 



.$0.0312 



.64 



Square yard. 



$0.0018 



.19 



Square yard. 

 $0. 2884 



Per cent of total cost 



21.71 







52086°— Bull. 407— 1( 



1 Does not include shoulders. 

 —3 



