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EXAMINATION OF BITUMINOUS ROAD MATERIALS. 19 
VOLATILIZATION TEST. 
EQUIPMENT. 
1 constant-temperature hot-air oven with rubber tubing. (Fig. 11.) 
1 thermo-reeulator. (Fig. 11-a.) 
2 chemical thermometers reading from —10° C. to 250° ©. 
1 tin box, 6 centimeters in diameter by 2 centimeters deep. 
1 analyticat balance, capacity 100 grams, sensitive to 0.1 milligram. 
METHCD. 
The object of the volatilization test is to determine the percentage 
of loss which the material undergoes when 20 grams in a standard- 
sized container are subjected to a uniform temperature of 163° C. for 
five hours, and also to ascertain any changes in the character of the 
material due to such 
heating. 
The oven shown in 
figure 11, known as 
the New York Test- 
ing Laboratory oven, 
is used by the Office 
of Public Roads and 
Rural Engineering, , 
although any other 
form may be used 
that will give a uni- 
form temperature 
throughout all parts 
where samples are 
placed. The bulb of 
one of the thermometers is immersed in a sample of some fluid, non- 
volatile bitumen, while the other is kept in air at the same eon 
The first theca serves to show the temperature of the samples 
during the test, while the latter gives prompt warning of any sudden 
changes in temperature due to irregularities in the gas pressure, etc. 
Before making the test the interior of the oven should show a tem- 
perature of 163° C. as registered by the thermometer in air. The tin 
box is accurately weighed after carefully wiping with a towel to 
remove any grease or dirt. About 20 grams of the material to be 
tested is then placed in the box. The material may then be weighed 
on a rough balance, if one is at hand, after which the accurate weight, 
which should not vary more than 0.2 gram from the specified amount, 
is obtained. It may be necessary to warm some of the material in 
order to handle it conveniently, after which it must be allowed to 
cool before determining the accurate weight. 
Fig. 11.—New York Testmg Laboratory oven. 
