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Ahmed Hani Salem Al-Omari
Civil Engineering
431900
Abstract:
We defined the softening point as the temperature at which a disc of bitumen softens enough
to allow a standard ball resting on it to move downward a distance of 25 mm.
Introduction:
Because the softening of a bituminous material does not take place at any definite
temperature, but rather involves a gradual change in consistency with increasing temperature,
any procedure that is adopted for determining the softening point must be of a somewhat
arbitrary nature. The procedure in common use in highway materials laboratories is known as
the "ring-and-ball method" and may be applied to semisolid and solid materials.
Practically, the temperature at which the softening bituminous material touch the bottom
metal plate placed 25 mm below the rings holders is recorded as the softening point.
Objective:
To obtain the point at which the bitumen becomes softening to use it to:
 Classify bitumen according to their susceptibility to heat.
 Classify bitumen according to their suitability to use in hot or cold regions.
 Check the uniformity of sources supplies.
 Indicate the tendency of bitumen to flow at elevated temperatures.
Equipments & Apparatus:
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Two brass rings.
Two 9.5 mm diameter steel balls, each weight 3.5 g.
Ball centering guides.
Flat brass plate.
Water bath in the form of a glass vessel.
Heating source.
Stirrer.
Thermometer.
Ahmed Hani Salem Al-Omari
Civil Engineering
431900
Procedure:
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We will get two-ring assembly to put them into a piston.
Fill the bath with water.
Heat the sample carefully until we arrive the starting temperature.
Put the ball at the center by the ball centering guide.
We heat in a rate of 5 0 C/min.
Record the point when the sample reach the metal plate.
Data & Analysis:
o
At 5
0
C
Ball
Softening Point (
1
2
AVG
0C)
59.0
59.5
59.25
Table ( 1 )
o
If water was not the liquid and the result was > 800 C, adjust the values as follows:
- The correction factor should be ( - 4.2 0 C ), as asphalt material.
- As using the asphalt material we follow this rule:
SP (water) = 0.974 * SP (ethylene glycol) – 1.44 0C.
Discussion & Conclusion:
o If the difference between the two samples in the same test exceeds 1 0C, the test must be
repeated.
o As we looking for our sample we can see that it has a low viscosity, so we can say that it
can be used in Jordan and Sweden but not in Kuwait because the hot weather in there.
o When we change the liquid in the bath there will be different in the results because every
liquid has a different boiling point and that affected the softening point, so the lower
boiling point need low temperature.
o Because the water has a boiling point @ 100 0 C; we can not use it as a liquid for testing
material having high softening points.
o When we increasing the rate of heating, the softening point will be less than the standard
( original ).
o If there is sand in the sample the boiling point will be increase, then the softening point
will be increase.
o When we use the same sample many times in this test ( reheating and retesting ) the
results will have an error in the softening point because that will make the material less
viscous and we will get error in the results.