Group C2BEC 307 Highway LaboratoryLaboratory 3 – Softening Test

Experiment 3: Softening Test

3.0 Introduction

The softening point is defined as the mean of the temperatures at which the bitumen disks

soften and sag downwards a distance of 25 mm under the weight of a steel ball. Instead, as the

temperature rises, these materials slowly change from brittle or very thick and slow-flowing

materials to softer and less viscous liquids. For this reason, the determination of 'softening point'

must be made by a fixed, arbitrary and closely defined method if results are to be comparable.

In general, with materials of these types, softening does not take at a definite temperature.

When temperature rises, these materials gradually and imperceptibly change from brittle or

exceedingly slow-flowing materials to softer and less vicious liquids. For this reason, the

determination of the softening point must be made by a fixed, arbitrary and closely defined

method if the results are to be comparable. This method is useful in determining the consistency

of bitumen in establishing the uniformity of shipments or sources of supply.

Being very simple in concept and equipment, the Ring-and-Ball Test has remained a

valuable consistency test for control in refining operations, particularly in the production of air-

blown bitumen. It is also an indirect measure of viscosity or, rather, the temperature at which a

given viscosity is evident. The softening point value has particular significance for materials

which are to be used as thick films, such as joint and crack fillers and roofing materials. A high

softening point ensures that they will not flow in service. For bitumen of a given penetration, the

higher the softening point the lower the temperature sensitivity.

Research has shown that, for conventional paving grade bitumen, the Ring-and- Ball

softening point temperature is the same as that which would give a penetration of 800 d-mm, can

be used to compute the Penetration Index.

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Group C2BEC 307 Highway LaboratoryLaboratory 3 – Softening Test

3.1 Objective

To determine the temperature at which phase change occurs in the asphalt cement. It is measure

by ring and ball accordance with ASTM D36.

3.2 Apparatus

1. Steel ball

2. Ring

3. Ball-centering guide

4. Ring holder

5. Bath

6. Thermometer

3.3 Procedure

1. Hot asphalt is poured into the ring and cooled at room temperature for about 30 minutes. The

sample is then leveled.

2. The ring is then placed on the ring holder.

3. Maintained the temperature in the water at 5 ± 1oC for 40 minutes and kept the sample in the

water bath at a level of not less than 102 mm and not more than 108 mm from the bottom of

the bath.

4. Place the ball in each ball-centering guide by using forceps.

5. Then apply heat at rate of 5oC per minute and make sure it is increasing uniformly.

6. Record for each ring and ball temperature shown by the thermometer when the specimen

surrounding the ball touches the bottom plate.

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Group C2BEC 307 Highway LaboratoryLaboratory 3 – Softening Test

Figure 3: Apparatus for bitumen Softening Point Test.

3.4 Safety, Health and Precaution

a) Lab Coat – To prevent the harmful chemical expose to body when accident happened.

b) Safety Shoes - Safety footwear is designed to protect feet against a variety of injuries.

Impact, compression, chemical splashes and puncture are most common types of injuries.

Footwear should be chosen according to the hazard and should be properly rated.

c) Safety Glove – To protect hand from expose to harmful chemical.

3.5 Results

SOFTENING POINT OF BITUMEN (RING & BALL)

BS 2000: PART 58: 1983

Bitumen’s Grade: 80/100

TEST NO ºC AVERAGE (ºC)

SAMPLE (1) 49.249.2

SAMPLE (2) 49.2

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Group C2BEC 307 Highway LaboratoryLaboratory 3 – Softening Test

3.6 Discussion

Based on JKR specification (2008), the bitumen which is grade 80/100, the softening

point must be between 45 ºC to 52 ºC. The test that has been conducted shows that the softening

point is 49.2 ºC which is within the range that required under JKR specification. So, the test is

considered success.

To get the accurate data, the main factor that affected the result is the procedure during

transfer the bitumen into the water. The other factors are timing and the temperature, which is the

bitumen supposed to be held within room temperature in 30 minutes.

3.7 Conclusion

From the experiment that was carried out, bitumen that was tested produces a softening

point of 49.2oC. The test should be conducted the according to the procedure provided and the

time, environment and also the temperature should be aware.

3.8 References

Millard, R.S. (1993). Road building in the Tropics. Transport Research

Laboratory State-of-the-art Review 9, HMSO, London.

PWD (1992). PWD General Specification. Public Works Department,

Singapore 1987 (with amendments, 1992).

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Group C2BEC 307 Highway LaboratoryLaboratory 3 – Softening Test

3.9 Appendix

Figure 1: Apply heat at rate 5C per minute. Figure 2: Specimen cooled in cool water.

Figure 3: Ring is placed on ball. Figure 4: Thermometer immersed in water.

Figure 5: Hot asphalt poured into ring and

cooled.Figure 6: Ball touches bottom plate.

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