TESTS ON BITUMEN: - The various tests on bitumen materials are:
(a) Penetration Test. (b)
Ductility Test. (c)
Viscosity Test.
(d) Float Test. (e)
Specific Gravity Test. (f) Softening
Point Test.
(g) Flash and Fire point Test. (h) Solubility Test. (i)
Spot Test.
(j) Loss on heating test. (k) Water content test.
[1] Penetration Test: -The
penetration test determines the hardness or softness of bitumen by measuring
the depth in tenths of a millimeter to which a standard loaded needle will
penetrate vertically in five seconds.
Procedure: - [1] Soften the material to a pouring
consistency at a temperature not more than 600 C for tars and
pitches and not more than 900 C for bitumen above the approximate
respective softening points.
[2] Stir it
thoroughly until it is homogeneous and free from air bubbles and water.
[3] Pour the
melt in to the container to a depth of at least 10mm in excess of the expected
penetration.
[4] Protect
the sample from dust and allow it to cool in atmosphere at a temperature
between 15 to 300C for 1/2 to 2hours for 45mm deep container and 1
to 11/2 hours for 35mm deep container.
[5] Unless
otherwise specified carry out testing at a temperature of 25±0.10C.
[6] Place it
along with the transfer dish in the water bath at 25±0.10C. and allow it remain for 1/2 to 2hours for
45mm deep container and 1 to 11/2 hours for 35mm deep container.
[7] Fill the
transfer dish with water from the water bath to a depth sufficient to cover the
mould completely.
[8] Remove
the transfer dish along with the mould from water bath after specified period
of time and put it upon the stand of penetration apparatus.
[9] Adjust
the needle (previously washed, cleaned well with benzene and dried) just to
make contact with the surface of the sample.
[10] The sum
of the weights of the needle, carrier and super imposed weights i.e. the total
moving weight shall be 100±0.25grams.
[11] Bring
the pointer to zero.
[12] Release
the needle for five seconds and measure the distance penetrated.
[13] Make at
least three determinations at points on the surface of the sample not less than
10mm apart and not less than 10mm from the side of the dish.
[14] After
each test, return the sample and transfer dish to the water bath and wash the
needle with benzene and dry.
[15] In case
of material of penetration greater than 225 make three determinations on each
of two identical test specimens using a separate needle for each determination,
leaving the needle in the sample on completion of each determination to avoid
disturbance of the specimen.
