34. BULLETIN 257, U. S. DEPARTMENT OF AGRICULTURE. 
TaBLe 25.—Surface maintenance of 1911 experiments at Chevy Chase, Md., to December - 
Silas h lees 
Maintenance cost of experiment. Cost per square yard (cents). 
A er Date Area 
ment No Tata d Cre. Construc-| Maint 
Ea eted. yards). ustruc- alnte- 
Pp / 1912 1913 1914 Total. Fiat aaron Ul boa: 
1911 
ilepereat ate ere Cc si 1,581 £0.00 $0. 00 $91.33 $91. 33 46.18 ae 51.96 
Das, ne heat pecan ee dost 705 - 00 - 00 - 00 - 00 77.62 - 000 77.62 
Siameae asa Nov. 18 1550 00 _. 00 00 . 00 64. 69 - 000 64. 69 
AEA EIN Nov. 8 12559 . 00 4.05 1.90 5.95 57.16 - 383 57.54 
tas ams Dec. 2 1, 447 260. 26 2.31 67 263. 24 58. 27 18.192 76. 46 
Gre ee Nov. 23 1,555 . 00 3.47 - 00 3.47 68. 22 . 223 68. 44 
Wie Bo eea\\ DOD 131 1. 43 . 00 . 60 1. 43 59. 96 1.092 61.05. 
eee ee Ol ee 848 67. 88 . 00 133 69. 21 54. 80 8.162 62.96 
1912. 
Se Saaeaele Aug. 24 ae A/pul eee ee ae 80. 64 - 00 80. 64 39.59 5. 460 45.05 
Oe ers Se June 4 Gla eee 39. 65 44.78 84. 43 42.01 11.095 53. 11 
LORE) Cee | Nov. 22 LAOS iA| ees 2 19. 05 284. 64 303. 09 44.31 29. 920 74. 23 
shes erieece os Dec. 16 Sil alsa oe . 00 -00 | - 00 81.51 - 000 seaiginit 
SUPPLEMENTARY REPORT OF EXPERIMENTS MADE AT JAMAICA, N. Y.,- 
1911. 
OIL-CEMENT CONCRETE, OIL-ASPHALT, TAR, AND FLUXED NATIVE ASPHALT. 
The original report of these experiments was published in Circular 
No. 98, and reports of annual inspection and repairs may be found 
in Circular No. 99, Office of Public Roads, and in U. 8S. Depart- 
ment of Agriculture Bulletin No. 105. The following report covers 
the condition of the sections when inspected January 18, 1915. 
EXPERIMENT No. 1 (O1t-CEMENT CONCRETE). 
In May, 1914, the Borough of Queens highway department patched 
the bare spots which were reported in the inspection of December, - 
1913, with an application of hot, refined coal tar and sand, and the 
addition of ?-inch stone in the deeper holes. The bare spots had 
developed somewhat larger in the section treated with water-gas tar 
products than in that treated with refined coal tar. At the time of 
the inspection the entire section was in very good condition with the 
exception of about 20 small bare spots where the carpet coat had 
worn off. The entire coat seemed to be worn very thin. 
EXXPERIMENT No. 2 (Cut-Back Om AspHatT—MIxIna METHOD). 
‘In May, 1914, the condition of this experiment was a little worse 
than in December, 1913, and in consequence the entire section was 
scarified to a depth of 3 inches and about one-third of the soft 
bituminous top mixture was thrown away. The remaining mixture 
was then shaped and lightly rolled to a thickness of about 2 inches, 
after which it was covered with a thin layer of 3-inch stone, thoroughly 
rolled, and opened to traffic. The following day a thin layer of 
trap-rock screenings was rolled in. 
