Softening Point

1.0

OBJECTIVE

To determine the softening point of bitumen within the range 30 to 157 º C by means of the Ring-and-Ball apparatus.

2.0

PROCEDURE

1. Select one of the following both liquids and thermometers appropriate for the expected softening point. 2. Use the ice water to maintain the temperature of bath liquid at 5 ℃ . Starting bath liquid for 15 min. 3. Forceps was using to place a ball from the bottom of the bath in each bal centering point. 4. Bath liquids were boiled between 30 and 80 ° C . Use the thermometer to check the temperature of water. The starting temperature is 5 ± ℃ 5. The maximum permissible variation for any 1 min period after the first 3 min should be ± 0.5 ℃ . 6. Temperature of each ring and ball was recorded by thermometer to indicate the bitumen surrounding the ball touches the bottom plate.

3.0

RESULT AND ANALYSIS Timer Reading (minutes) 0 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Temperature (⁰C) 5 7 11 15 18 22 24 26 28 29 30 30.5 31 31.5 32 33 33.2

4.0

DISCUSSION a) The source and type of bitumen.

Bitumen is a non-crystalline viscous material, black or dark brown, which is substantially soluble in carbon disulphide (CS2), possessing adhesive and water-proofing qualities. It consists essentially of hydrocarbons and would typically comprise at least 80% carbon and 15% hydrogen, the remainder being oxygen, sulphur, nitrogen and traces of various metals. Asphalt is a word with different meanings. In American usage asphalt, or, in full, asphalt cement, is used to mean bitumen (or bitumen binder). In the term 'rock asphalt' it defines a mineral substance that may be impregnated with bitumen or pitch. Outside America the word asphalt means a mixture of bitumen and mineral aggregates laid as a road surface. Bitumen can be obtained from various sources. It occurs naturally, but for most purposes it is petroleum on which the world relies for its supplies of bitumen. The bitumen content of crude petroleum oil can vary between 15% and 80%, but the more normal range is 25% to 40%. The three broad classifications for crude oils are: bitumen based; paraffin based; or bitumen and paraffin based. Depending on the type of crude petroleum oil, bitumen is present either in the form of a colloidal dispersion, or in a true solution. During the refining process, as petroleum oils are taken away by distillation, the proportion of oil to bitumen particles changes. Instead of these particles being dispersed and relatively few in number, they become closer to one another and their size increases. Bitumen is a strong and durable adhesive that binds together a very wide variety of other materials without affecting their properties. Its durability is essential to major engineering projects such as roads and waterways where it must perform for up to 20 years or more.

b) Report the bath liquid in the test and quote the mean softening point of your specimen. Give comment.

For a given bitumen specimen, the softening point determined in a water bath will be lower than that determined in a glycerin bath. Since the softening point determination is necessarily arbitrary, this difference matters only for softening points slightly above 80˚C. under any circumstances, if the mean of the two temperature determined in glycerin is 80.0˚C or lower for bitumen or 77.5˚C or lower for coal-tar pitch. The softening point is the temperature at which a substance attains a particular degree of softness under specified conditions of test. The average softening point test is 33.1˚C. According to the reference that we used in this experiment, the type of bitumen used should achieve softening point 45°C 52°C. However, in our experiment, the softening point achieve only 33°C to melt which is to fast to melt. Other reason why the softening point not achieve as reference is specimen at brass ring not achieve at least 30 minutes before test during immersion process using ice and distilled water as in procedure even the temperature not more than 10°C. With all this carelessness, that may affect the result in overall experiment.

c) If the two test temperature differ by more than 1˚C, offer an explanation. The difference between the two test is not more than 1˚C. The temperature is accepted.

5.0

CONCLUSION

Refer to the range of the result of experiment, we can conclude that our penetration grades is 200-300 which is softening point at 33 ℃ as min value. Besides, the parallex error occur in case of reading of the temperature and it may effected the result of this experiment. The value of penetration index is -6 and the bitumen type is temperature susceptible bitumen (tars).