1124 
Journal of Agricultural Research 
Vol. V, No. 24 
Table II .—Results of an asphalt penetration test with a needle made from a steel drill 
rod 0.041 inch in diameter 
Taper of needles. 
Sample No. 
5284 (blown 
oil asphalt). 
Sample No. 
5963 (oil 
asphalt). 
Sample No. 
5985 (blown 
oil asphalt). 
Sample No. 
8928 (fluxed 
native 
asphalt). 
Standard. 
30 
153 
75 
109 
T^-inch taper. 
30 
148 
70 
106 
X-hich taper. 
32 
ISO 
74 
109 
T^-inch taper. 
34 
153 
80 
112 
It will be noted from the above that on all four samples, representing 
three different types of material, the needle with %-mch. taper gave results 
in comparatively closer accord with those obtained by the standard 
needle than did the others. Three new needles of this type were there¬ 
fore made and tested in comparison with the standard needle on various 
types of bituminous material having a wide range of penetration. The 
results are given in Table III. When it was found that all three needles 
checked with the standard throughout, the No. 1 new needle was run 
comparatively with the standard on six additional products, covering 
a still wider range of materials, in order to determine whether products 
varying in their general adhesive character might have any effect on the 
results. It will be noted by referring to Table III that the needle which 
the writers have designed yields in all cases results practically identical 
with those obtained with the standard needle. In cases where no results 
are given for the No. 3 needle the omission is due to the fact that the 
samples were run before the third needle had been prepared. In all cases 
but one the results are given by two operators. 
Table III. —Results of a comparative test of the new penetration needle with a standard 
needle 
Sample No. 
Material. 
Standard 
needle. 
Needle 
No. 1. 
Needle 
No. 2. 
Needle 
No. 3. 
Oper¬ 
ator 
A. 
Oper¬ 
ator 
B. 
Oper¬ 
ator 
A. 
Oper¬ 
ator 
B. 
Oper¬ 
ator 
A. 
Oper¬ 
ator 
B. 
Oper¬ 
ator 
A. 
Oper¬ 
ator 
B. 
5959 
C28d. 
Blown Texas oil asphalt . 
8 
8 
9 
9 
8 
8 
.. do. 
30 
31 
32 
32 
33 
32 
Mexican oil asphalt. 
41. 5 
41.5 
43 
41.5 
41 
41' 
5 
8961 
California oil asphalt. 
49 
47 
47 
48 
48 
49 
49 
47 
68l I 
Texas oil asphalt . 
77 
76 
92 
77 
78 
76 
76 
8916 
. do. 
93 
95 
95 
93 
93 
8962 
California oil asphalt. 
94 
94 
94 
94 
93 
93 
94 
94 
Texa* 5 oil asphalt 
108 
no 
no 
no 
109 
108 
5406 
Oil asphalt (cut-back). 
114 
114 
in 
in 
114 
114 
Ii3 
112 
8966 
Mexican oil asphalt. 
118 
121 
118 
120 
117 
117 
117 
119 
8970 
119 
118 
117 
119 
119 
119 
118 
119 
8963 
California oil asphalt. 
135 
133 
134 
133 
135 
133 
135 
136 
5381 
Oil asphalt (cut-back). 
133 
134 
135 
135 
135 
135 
134 
135 
5963 
Texas oil asphalt ... 
151. 5 
150 
150 
151 
151. s 
151 
5559 
Oil asphalt (cut-back). 
168 
170 
170 
170 
170 
168 
170 
169 
8963 A 
Fluxed California asphalt. 
192 
193 
192 
194 
195 
196 
195 
193 
8963B 
236 
239 
235 
236 
234 
238 
233 
234 
8963 C 
do. 
292 
295 
295 
295 
291 
ctt8 
Fluxed Trinidad asphalt 
83 
85 
83 
85 
5110 
Flpxed Piihan asphalt . 
65 
65 
65 
67 
5 1J 9 
8326 
Fluked Bermudez asphalt .... 
46 
46 
46 
8615 
do . 
*T J 
II 1 ? 
115 
140 
113 
n s 
6293 
fiilsnnitp oil asphalt 
140 
138 
59 
138 
do , 1 , t t , ., , . 1 1 . . . 1 1 .. 1 « . T f .. t ^ 1 1 f t T 
60 
60 
60 
5 io 4 
