1. Which of the below IS code gives guidelines for the flash and fire point test?
a) IS 1202
b) IS 1208
c) IS 1203
d) IS 1209
Explanation: IS 1209 gives the details for conducting the flash and fire point test. IS 1202 deals with specific gravity, IS 1208 with ductility and IS 1203 gives details for penetration test.
2. Float test is used to identify the impurities in bitumen.
a) true
b) false
Explanation: The viscosity of bitumen cannot be found easily in some consistency range using viscometer or penetration test. In such cases, the float test is carried out on bitumen to assess its viscosity.
3. The ductility value of sample tested is found to be 80 mm. What is the grade of the sample?
a) VG-40
b) VG-30
c) VG-20
d) VG-10
Explanation: The ductility value of bitumen can vary from 5 to 100 mm. For grade VG-40, the minimum ductility is 25mm, for VG-30 it is 40mm, VG-20 it is 50mm and for Vg-10 it is 75mm. The value for the sample is 80mm, hence it should be of the grade VG-10.
4. What height should the steel ball fall through in a softening point test to ascertain the temperature?
a) 25 cm
b) 2.5 cm
c) 50 cm
d) 5 cm
Explanation: As per IS 334-1982, the definition for softening point is that temperature at which the standard steel ball passes through the sample and falls through a height of 2.5 cm when heated under water at standard test conditions.
5. Solubility test in bitumen is used to determine ______ of bitumen.
a) Contamination
b) Solubility
c) Dispersion
d) Composition
Explanation: Bitumen is almost completely soluble in solutions of carbon disulphide and carbon tetrachloride. So, after conducting the solubility test, if there are any undissolved particles, those would indicate the presence of impurities or the contamination of bitumen.
6. What is the standard load applied to the sample when the needle is immersed in the penetration test?
a) 100 mg
b) 100 g
c) 200 mg
d) 200 g
Explanation: The standard load for the penetration test is 100 g and it is in accordance with IS 1203:1978. The needle is allowed to penetrate the sample and it imposes a load of 100 g when it does so.
7. The formula to calculate the specific gravity of bitumen is given by \(\frac{c-a}{(b-a)-(d-c)}\). Which of the below symbol and explanations is incorrect?
a) a – weight of specific gravity bottle
b) b – weight of specific gravity bottle filled with distilled water
c) c – weight of specific gravity bottle filled with bituminous material
d) d – weight of specific gravity bottle half filled with bituminous material and rest with water
Explanation: The symbol c indicates the weight of specific gravity bottle half filled with bituminous material. All the measurements are taken in grams. All the symbols are relative to each other and by combining them, the specific gravity can be found out.
8. What are the acceptable viscosity limits for bitumen emulsion RS-2 when tested using saybolt furol viscometer?
a) 30 – 150
b) 20 – 100
c) 50 – 300
d) 100 – 300
Explanation: The test is conducted as per IS 3117 and the viscosity limits are mentioned in IS 8887. The acceptable viscosity limits for RS-2 are 100 to 300. For RS-1, it is 20 to 100; for MS, it is 50 to 300; for SS-1, it is 20 to 100 and for SS-2, it is 30 to 150.
9. When is the bitumen sample considered cracked in the spot test?
a) Spot spreads
b) Spot with uniform colour
c) Spot fades
d) Spot with varying colour
Explanation: The spot test consists of dropping two spots at different times on a filter paper. The spot spreads and if the colour is varying in the form of annular rings, darker at the centre, the bitumen sample is sadi to have cracked. It is not cracked if the spot spreads and has a uniform colour.
10. At what speed is the specimen pulled in the ductility test?
a) 50 cm per minute vertically
b) 50 mm per minute horizontally
c) 50 mm per minute vertically
d) 50 cm per minute horizontally
Explanation: The sample is filled in the briquette mould and the end clips are pulled uniformly at 50 mm per minute in the horizontal direction. When pulled horizontally, the sample would stretch and break, giving the ductility value.