1. What is the orifice size and temperature for testing cut-back bitumen using orifice viscometer?
a) 4 mm at 25°C
b) 10 mm at 45°C
c) 4 mm at 45°C
d) 10 mm at 50°C
Explanation: The orifice viscometer can be used to test the viscosity of tar and cut-back bitumen. For testing tar, the conditions are 10 mm orifice at 35/40/45/55°C. for cut-back bitumen, the conditions are 4mm orifice at 25°C or 10 mm orifice at 25/40°C.
2. Bitumen having a higher softening point is preferred in hot climates.
a) true
b) false
Explanation: Higher softening point would indicate that the bitumen sample has lower temperature susceptibility. It would take some time for the bitumen sample to be liquid. It can be used in hot climatic conditions, as higher temperature is required for bitumen to attain the liquid state.
3. The dial reading after conducting a penetration test is found to be 73. What is the penetration value of the sample?
a) 730 mm
b) 73 mm
c) 7.3 mm
d) 0.73 mm
Explanation: The dial readings are marked from zero to four hundred. Each reading is 1/10th of a millimetre i.e. if the reading is 73, the corresponding penetration value is 7.3 mm.
4. What does TSR stand for?
a) Temporary Softening Rate
b) Thermal Sensitivity Ratio
c) Terminal Strength Rate
d) Tensile Strength Ratio
Explanation: TSR of bitumen gives a measure of its resistance to moisture susceptibility.it is important to ascertain the sensitivity of bitumen to water, it affects the binding property. A higher TSR value indicates good resistance to moisture.
5. Kinematic viscosity is related to absolute viscosity by ______
a) Volume
b) Mass
c) Weight
d) Density
Explanation: Kinematic viscosity is determined by the ratio of absolute viscosity to density. The unit of kinematic viscosity is m2/s and the unit of absolute viscosity is N s/m2. Density is used to relate both the terms.
6. There are two methods to find the specific gravity of bitumen.
a) true
b) false
Explanation: As per IS 1202:1978, there are two methods to determine the specific gravity of bitumen. The first method is using a pycnometer and the second one is using a balance beam method. The descriptions for both are given in the code.
7. What is the temperature of the oven in the loss on heating test?
a) 163°C
b) 153°C
c) 110°C
d) 120°C
Explanation: As per IS 1212-1978, the oven is heated to a temperature of 163±1°C and the sample is placed in it for 5 hours. The container is heated to 100-110°C for 30 minutes, then cooled and weighed. Then the sample is poured into it.
8. What is the speed of rotation of stirrer used in flash and fire point test for cut-back bitumen?
a) 90 rpm
b) 60 rpm
c) 70 rpm
d) 50 rpm
Explanation: As per IS 1209-1978, the speed of rotation for bitumen is 60 rpm. For cut-back bitumen, it is taken as 70 to 80 rpm. All other things for conducting the test are the same for all types of bitumen.
9. What is the temperature at which softening point test has a different procedure??
a) 90°C
b) 80°C
c) 75°C
d) 65°C
Explanation: The test procedure is explained in IS 1205-1978. There is a change in the bath used when the material of softening point below 80°C and above 80°C is tested. For below 80°C, the bath used is water and for above 80°C, the bath is glycerine.
10. Marshall mix design method was developed by ______ in the year ______
a) George Marshall, 1959
b) George Marshall, 1939
c) Bruce Marshall, 1959
d) Bruce Marshall, 1939
Explanation: Marshall mix design method was developed by Bruce Marshall in the year 1939. He used to work in the Mississippi highway Department and his method was refined by the US army. George Marshall was an American soldier and he passed away in 1959.