46 
BULLETIN 040, TJ. S. DEPARTMENT OF AGRICULTURE. 
It is sometimes necessary to make several trials before the desired result is obtained, 
"When the required penetration is reached, the residue left from evaporation is weighed 
and its per cent of the original sample taken is computed. 
29. TEST FOR PENETRATION OF BITUMINOUS MATERIALS. 
(A. S. T. M. Standard Method, Serial Designation: D 5-16.) 
I. DEFINITION. 
(1) Penetration is defined as the consistency of a bituminous material expressed as 
the distance that a standard needle vertically penetrates a sample of the material 
under known conditions of loading, time, and temperature. Where the conditions 
of test are not specifically mentioned, the load. time, and temperature are understood 
to be 100 grams. 5 seconds. 25° C (77° P.), respectively, and the units of penetration 
to indicate hundredths of a centimeter. 
Fig. 24.— New York Testing Laboratory penetrometer. 
n. APPARATUS. 
(2) The container for holding the material to be tested shall be a flat-bottom, cylin- 
drical dish, 55 mm. (2^ inches) in diameter and 35 mm. (If inches) deep. 8 (See 
figs. 21 and 25.) 
(3) The needle 9 for this test shall be of cylindrical steel rod 50.8 mm. (2 inches) 
long and having a diameter of 1.016 mm. (0.01 inch) and turned on one end to a 
sharp point having a taper of 6.35 mm. (one-fourth inch). 
(1) The water bath shall be maintained at a temperature not varying more than 
0.1° C. from 25° C. (77° F.) The volume of water shall be not less than 10 liters and 
the sample shall be immersed to a depth of not less than 10 cm. (4 inches) and shall 
be supported on a perforated shelf not less than 5 cm. (2 inches) from the bottom of 
the bath. 
3 This requirement is fulfilled by the American Can Co.'s gill style ointment box, deep pattern, 3-ounce 
capacity. 
9 It is recommended that the Roberts No. 2 parabola needle be used until such a lime as Committee D-4 
of the American Society for Testing Materials are in a position to make a recommendation relative to a 
type of needle which may generally be obtained. 
