KEROSENE PLUS TAR, KEROSENE PLUS
ASPHALT CEMENT OR ASPHALT CUTBACK.
BEADS FORMED BY ASPHALT EMULSION IN
Figure 8-22.Solubility test for asphalt, tar,
When you perform the volubility test
and the bituminous material dissolves, an
asphalt productasphalt cement or asphalt
cutbackis present. At room temperature
(77 F) asphalt cements are solids, and asphalt
cutbacks are fluids. With these facts in mind,
you may run a second test, a pour test, to
determine whether a sample is an asphalt
cement or an asphalt cutback.
In the pour test, an attempt is made to pour
the material from a small container. Asphalt
cements are solids and will not pour. Asphalt
cutbacks are fluids at 77 F and will pour (fig. 8-
A pour test is also used to identify the 12
viscosity grades of tar. Viscosity grades of road tar
are comparable to the viscosity grades of asphalt
cutbacks and asphalt cement (table 8-5). RT-1, the
most fluid, is similar in viscosity to the grade 30 of
the rapid-curing, medium-curing, and slow-curing
types of asphalt cutbacks. RT-8 is similar to grade
800 asphalt cutback. RT-12 has the approximate
Road tar grades 4, 5, and 7, which are identical
in appearance to road tar cutback grades 5 and 6 may be
distinguished through a smear test. Like asphalt
ASPHALT CEMENT ON LEFT.
ASPHALT CUTBACK ON RIGHT.
LEFT TO RIGHT: ASPHALT CUTBACKS GRADE
30, 70, 250, 800, AND 3,000 THREE SECONDS
AFTER TIPPING FULL JARS.
THIRTEEN SECONDS AFTER
TIPPING FULL JARS.
Figure 8-23.Pour test for asphalt
cutbacks, road tar cutbacks cure rapidly since they
are thinned with highly volatile materials that
evaporate quickly and leave a sticky substance within
a 10-minute period. On the other hand, because the
fluid coal oil in road tars evaporates slowly, road tars
will remain at the same consistency at the end of an