exp ring n ball

Ring and Ball (R and B) Softening Point Test

INTRODUCTION

The softening point is defined as the mean of the temperatures at which the bituminous material

is softened and sagged downward at a distance of 25 mm under the weight of steel ball. In

general, with materials of these types, softening does not take place at the definite temperature.

As the temperature rises, the bituminous material gradually and imperceptibly changes from

brittle or exceedingly slow flowing material to softer and less viscous. 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 (MS 687: 1995).

This method is useful in determining the consistency of bituminous material assign

element in establishing the uniformity of shipments or sources of supply. (The engineering term

consistency is an empirical measure of the resistance offered by a fluid to continue deformation

when it is subjected to shearing stress). The consistency is a function of the chemical constituents

of bituminous material viz. the relative proportions of asphaltenes, resins and oils. The type and

amount of these constituents are determined by the source of crude petroleum and the method of

processing at the refinery plant (ASTM Designation D36).

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OBJECTIVES

The OBJECTIVES lives of this experiment are:

i. To determine the temperature at which a given bituminous material specimen reaches a

certain degree of softness.

ii. To deduce the penetration index (Pl) value of the specimens directly from PI Nomograph

in Figure 2.2.

APPARATUS

Two steel balls of diameters 9.5 mm and each weighing 3.50 ± 0.05 g, tapered ring made of

brass, ball-centering guides, ring moulds and suspended ring holder, thermometers, ice cubes,

stop watches, spatula, forceps, magnetic stirrers, beakers and heaters.

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PROCEDURES

i. Some water was poured in a beaker to prepare a water bath. A magnetic stirrer was put in

the water bath. Some ice cubes was also put into the beaker.

ii. The temperature of the water bath was measured by a thermometer. A suspended ring

holder was then put in the water bath, followed by placing the thermometer in the centre

part of the suspended ring holder.

iii. The temperature of the water bath was maintained at 5° ± 2°C for 15 minutes. The

specimens in the ring holders were placed once stabilizing the temperature.

iv. A few minutes before a-fifteen minute conditioning period was set, the steel balls was

placed in the ball-centering guides using a forceps.

v. After 15 minutes, an electric heater was positioned just next to the suspended ring holder

and switches it on.

vi. The water bath which should be heated up at 5° ± 2°C per minutes were monitored and

make sure it is increasing uniformly, that is, the increment of 4° - 5°C per minute and no

more than 7°C.

vii. Temperature and the corresponding time was noted and recorded at instant the

bituminous material was sagged downward, dropping at the base plate of the suspended

ring holder.

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RESULTS OF OBSERVATIONS

Timer

Reading

(Minutes)

Temperature

(°C)

Timer

Reading

(Minutes)

Temperature

(°C)

0 5 11 27

1 7 12 30

2 8 13 32

3 10 14 34

4 11 15 36

5 13 16 38

6 15 17 40

7 19 18 42

8 20 19 44

9 23 20 45

10 25 21 46

NOTE:

The test is recommended to be done all over again if the difference between the two temperature

of the water bath for two steel balls exceeds 1OC (MS 687: 1995).

Softening point, R = (R1 + R2) / 2

= (45 + 46) / 2

= 45.5

Where, R= average temperature of the water bath for two steel balls.

The temperature and the corresponding time at which a tested bituminous material specimen

reaches a certain degree of softness:

Softening point: 45.5 °C and 20.5 minutes

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DISCUSSION

Table 1.0 Characteristic of bitumen according to PI value

PI values can be used to determine the stiffness (modulus) of a bitumen at any temperature and

loading time. It can also, to a limited extent, be used to identify a particular type of bituminous

material. One drawback of the PI system is that it uses the change in bitumen properties over a

relatively small range of temperatures to characteristic as bitumen; extrapolations to extremes of

the behaviour can sometimes be misleading. PI range between -1 < PI < +1 is suitable for road

construction.

1. From the data above, the temperature of the first specimen to drop is 45°C while for the

second specimen is 46°C. From these last two data, we can determine the softening point

by taking the average, and the value that we get is 45.5°C.

2. It is observed that the softening point increases by the addition of polymer to the bitumen.

The influence over the softening point is depended on the chemical nature of the polymer

added. This will differ in the classification of bitumen.

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3. Bitumen can be classified into several grades and each grade has different softening point

and physical characteristics. For this experiment, the grade used is 80/100. As the

temperature rises, the bitumen gradually becomes softer and less viscous. Based from the

result, the maximum temperature for this specimen to sagged downward is at 46°C.

Compared to the other group that used a grade of 60/70, the temperature for the specimen

to soften is a bit higher. Thus the higher the grade, the softer the bitumen.

4. After relate to the depth of penetration, we can determine that the penetration index or PI

for grade 80/100 is -3.4. According to the table of characteristic, since the value is less

than -2, the type of bitumen is Temperature Susceptible Bitumen (Tars).

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CONCLUSION

1. This test method covers the determination of the softening point of bitumen in the range

from 30 to 157°C (86 to 315°F) using the ring-and-ball apparatus immersed in distilled

water (30 to 80°C).

2. The softening point is useful in the classification of bitumen, as one element in

establishing the uniformity of shipments or sources of supply, and is indicative of the

tendency of the material to flow at elevated temperatures encountered in service.

3. Rigid adherence to the prescribed preparation of specimens and heating is absolutely

essential for reproducibility of the results. The mean temperature of the two specimens

(which shall not differ by more than 1oC) is recorded as the softening point. This

temperature is to be used in conjunction with the penetration value to obtain the

Penetration Index (PI). The temperature of the two specimens is 45 oC and 46 oC, which

the difference is 1 ºC.

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RECOMMENDATIONS

Recommended value of Softening point indicates the temperature at which binders possess the

same viscosity. Bitumens are viscoelastic materials without sharply defined melting points.

Rather, the change of state from solid to liquid is gradual over a wide range of temperature.

Softening point has particular significance for materials to be used as joint and crack fillers.

Higher softening point ensures that they will not flow during service. Higher the softening point,

lesser the temperature susceptibility. Bitumen with higher softening point is preferred in warmer

places.

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REFERENCES

[1] AB. Karim, S. N., Tey, L.S., Ishak, S.Z., Abd Rahman, M.Y., and Adnan, M.A., (2010).

Highway engineering laboratory manual, 2nd .Edition, University Publication Centre

(UPENA) : UiTM, 5 – 8.

[2] ASTM D0036 - 06: 2008. Standard Test Method for Softening Point of Bitumen (Ring-and-

Ball Apparatus), Annual Book of American Society for Testing and Materials (ASTM)

Standards, Volume 04.04, Roofing Standards, ASTM International, PA, USA.

[3] Historical Standard: ASTM D36-95: 2000 el. Standard Test Method for Softening Point of

Bitumen (Ring-and-Ball Apparatus), Annual Book of American Society for Testing and

Materials (ASTM) Standards, Volume 04.04, Roofing Standards, ASTM International, PA,

USA.

[4] Malaysia. Standards and Industrial Research Institute of Malaysia (SIRIM), 1995. MS 687:

1995. Malaysian Standard: Method of Test for Softening Point of Bitumen (Ring-And-Ball

Apparatus) (First Revision), Shah Alam: SIRIM Board.

[5] Website Google search : http://theconstructor.org/practical-guide/softening-point-of-

biuminous-material/2571/

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http://theconstructor.org/practical-guide/softening-point-of-biuminous-material/2571/

http://theconstructor.org/practical-guide/softening-point-of-biuminous-material/2571/


APPENDICES

Sample of hot bituminous Beaker and heater

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Magnetic stirrer

Thermometer Suspended ring holder

Steel Ball

Ring mould


i) Before the experiment starts ii) Ice cubes were put into beaker

to reduce the temperature

iii) The bituminous material is sagged downward

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Group members (from left) :

Siti Sarah, Nurul Hidayah, Nur Insyirahnadia, Siti Aishah and Nur Asyikin.

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exp ring n ball

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