DUST PREVENTION AND ROAD PRESERVATION, 1916. 61 
TABLE 65.— Materials and cost data for surface re-treatment, Chevy Chase, Md., in 1916. 
Experi- E = 
xperi- Experi- 
ae ment No. | ment No. 
Item. SPAS 9, asphal- | 10, asphal- 
tar Hoes tie petro- | tic petro- 
eration leum. leum. 
PRO EEORE CG: sae tee ore as Bee ace se sah see sesso uare yards: - 1,477 761 1,013 
Quantity of material per square yard: 
I FLLIMIINOHS WIALOLTIAL -. 0" dose oes cisco e = once oceans ae -gallons. “0.149 0. 289 0. 299 
Gravee oe) aoe e eedies | Soodos 1obise nuke eee aee cubiesvards=.|2:=-22-.52.- - 0138 -0114 
SHNEG! -.- He CeR CO CBG EOE Se GEDEC OCC CED ESE SS Dna Se HaHa Reena dose: OULS oi ccmese cn ascles aiceen cess 
Cost per square yard (cents): 
AUMIMINONSIMN ALCL Abs e)) 2s 2 a= 2s sos ess = os =~ ones 1.85 3.47 3.59 
PIG cob dee bots cn bebdods beesbd odode eseerocdeseesecsadeds Sdest das sécc 3.53 2.91 
DG eee os ee ea se ee eee oh aoe sebigrtaces sock. Sues PAA Aer. Sse eee See 
Cleaning surface......---..------------------------------------- -13 -03 -30 
PRA NN SoH AL CEIAISae oo ped = ss = no Noreen eee ee eine Dose 41 54 -49 
Applying bituminous materials........-....--.-.--------------- -55 -19 E23 
Applying sand or gravel...------------------------.------------ -25 -26 -36 
SVE DB ATSIOE  cccoc ose sdctnes sooeececedeode odectoce ae seco seseesec -41 74 1.02 
BRS a mee eee ree ae ee oe cies ocinc (oe = aidteimiasietel= Slee sie e/alce= am 6.55 8.76 8.$9 
TABLE 66.—Surface maintenance costs of 1911 experiments at Chevy Chase, Md., 
December 31, 1916. 
Maintenance cost of experiments. Total cost per square yard. 
ess, Total for 
Experiment No. 
Con- Main- 
Donat 1916 Total. | struction. | tenance. Total, 
1915 
Cents. Cents. Cents: 
$128. 45 $4. 23 $132. 68 46. 8. 5 
16.14 4.55 20. 69 64. 42 2.93 67.35 
14.71 5.92 20. 63 64.69 1.33 66. 02 
46.77 10.32 57.09 57.18 3. 67 60. 85 
305.50 7.75 313.25 58.27 21.65 79. 92 
2 2 8.85 44.47 & = 2.86 71. 08 
oO is 
(eee \ 2.90 103.19 { a \ 10.54 66.03 
130. 80 117.05 247.85 39. 59 16.78 56.38 
148. 22 77.97 226.19 42. 01 29.72 71.73 
437. 84 131.16 569. 00 44.31 56.17 100. 48 
0.00 ad 5. 88 81.51 1.56 83.07 
Section No 11—WNative asphalt emulsion, macadam surfacing.— 
This section never has been re-treated and it has required no patching 
until the past season, when a few slight breaks were repaired. The 
mat was breaking rapidly and at date of inspection there were 
numerous places where the aggregate was exposed and four or five 
places where raveling was imminent, with moisture coming through 
about 60 per cent of the surface. It was probable that considerable 
patching and a reseal would be required in the spring. 
Maintenance during 1916—In addition to the general re-treatments, 
as above described, the patrol system of maintenance was continued 
during the year. Table 66 presents the total cost of all maintenance, 
including the re-treatments shown in Table 65 
