DUST PREVENTION" AND ROAD PRESERVATION. 
Table 1. — Description of various sections of experiment No. 3. 
Section. 
Location (stations). 
Paint coat. 
Carpet coat. 
From — 
To— 
A 
12+50 
15+00 
17+50 
20+00 
21 + 25 
22+50 
25+00 
26+50 
28+00 
29+50 
15+00 
17+50 
20+00 
21+25 
22+50 
25+00 
26+50 
28+00 
29+5(5 
30+90 
None 
Refined coal tar. 
B 
do 
Water-gas tar preparation 
No. 2. 
Fluxed native asphalt No. 2. 
c 
do 
D 
Water-gas tar preparation 
No. 1. 
Native asphalt emulsion .... 
Water-gas tar preparation 
No. 1. 
Do. 
E 
Fluxed native asphalt No. 1. 
F 
Oil-asphalt No. 1. 
G 
Refined coal tar. 
H 
do 
Water-gas tar preparation 
No. 2. 
I 
do 
J 
do 
Oil -asphalt No. 2. 
Analyses of the various materials used are given in Tables Nos. 2 
and 3. A sample of the asphaltic emulsion was not obtained, but it 
was the same product as was used on section No. 11 of the 1911 project 
and reported in Circular No. 99. For a paint coat the emulsion was 
diluted with an equal volume of water. 
From station 33+60 to station 34 + 15 the concrete was given a 
paint coat of the crude water-gas tar, the analysis of wdiich is given in 
Table 2. The application was made at the rate of approximately 0.1 
gallon per square yard. It was absorbed to a slight extent and soon 
dried, and was distinctly evident as a brown stain on the surface wdien 
last inspected. 
Table 2. — Analyses of tar products used in surface treatment of concrete. 
Materials. 
Water-gas tar preparation. 
gas tar. 
No. 1. 
No. 2. 
A and G. 
D and F. 
B and H. 
Specific gravity 25°/25° C 
1.082 
1.219 
1.108 
14.0 
1.144 
Viscosity, Engler, 50° C, 50 c. c. spe- 
cific 
Float test 32° C 
1' 23" 
40" 
16.29 
3' 27" 
Float test 50° C 
1' 15" 
Per cent of free carbon 
0.32 
0.25 
0.95 
By vol- 
ume. 
By 
weight. 
By vol- 
ume. 
By 
weight. 
By vol- 
ume. 
By 
weight. 
By vol-) By 
ume. | weight. 
Distillation: 
Water 
P.ct. 
i7.5 
16.3 
il.l 
4 25.1 
6 16.4 
43.6 
P.ct. 
6.9 
5.1 
.8 
23.4 
15.5 
47.8 
P.ct. 
0.0 
2.8 
3.3 
5 16.4 
7 10.0 
72.5 
P.ct. 
0.0 
.5 
.2 
14.7 
8.7 
75.8 
P.ct. 
0.0 
il.7 
1.6 
118.5 
8 18.4 
60.8 
P.ct. 
0.0 
1.4 
.4 
16.3 
17.0 
64.8 
P.ct. 
0.0 
1.2 
1.2 
17.5 
9 11.8 
80.3 
P.ct. 

First light oils to 110° C 
1 
Second light oils 110° to 170° C. . . . 
Heavy oils 170° to 270° C 
.2 
6 4 
Heavy oils 270° to 315° C . . . 
10 4 
Pitch 
82 8 
100.0 
99.5 
100.0 
99.9 
100.0 
99.9 
100.0 
99.9 
1 Clear. 2 One-half solid, s Cloudy. < Three-fourths solid. » Two-thirds solid. 6 Two-fifths solid. 7 Solid. 
8 Clear. Showed 7.5 per cent insoluble in dimethyl sulphate. A 315°-350° C. fraction showed 7.5 per 
cent, and a 350°-375° C. fraction showed 17.5 per cent insoluble in dimethyl sulphate. 
9 Clear. Thisjraction, and also a 315°-350° C. fraction and a 350°-375° C. fraction each showed 7.5 per cent 
insoluble in dimethyl sulphate. 
