1. Why is natural cement used very limitedly?
a) Brown in Colour
b) Standard consistency is not met with
c) Sets too quickly
d) Particle size is too fine
Discussion
Explanation: Natural cement sets very quickly after the addition of water and hence it is not quite workable. Artificial cement is preferred over this.
2. Who invented Portland cement and in which year?
a) William Aspdin, 1824
b) William Aspdin, 1840s
c) Joseph Aspdin, 1840s
d) Joseph Aspdin, 1824
Discussion
Explanation: Joseph Aspdin patented Portland cement in 1824. William Aspdin, his son is regarded as the inventor of modern Portland cement due to his developments in 1840s
3. What is the average particle size of cement?
a) 15 microns
b) 45 microns
c) 75 microns
d) 100 microns
Discussion
Explanation: Approximately 95% of cement particles are smaller than 45 microns and the average particle size is 15 microns.
4. What is the meaning of soundness of cement?
a) Ability to flow when mixed
b) Ability to make ringing noise when struck
c) Ability to form strong and sound structure
d) Ability to retain volume after setting.
Discussion
Explanation: When cement paste hardens and sets, it should not undergo any volume change. Soundness ensures this and is tested using Autoclave expansion test.
5. Time elapsed from the instance of adding water until paste ceases to behave as fluid is called:
a) Initial setting time
b) Final setting time
c) Intermediate setting time
d) Absolute setting time
Discussion
Explanation: Final setting time is the time required for cement paste to reach a certain state of hardness. Option c and d does not exist.
6. Which of the below mentioned is not a result of field test performed on cement?
a) There should not be any lumps
b) It should feel cold when you put your hand in bag of cement
c) The colour should be blackish grey
d) It should not be gritty when rubbed with finger
Discussion
Explanation: The colour of cement is normally grey with a greenish tint. There are different shades – lighter and darker, but it does not go as dark as blackish grey.
7. Which equipment is used to test the setting time of cement?
a) Core cutter
b) Vibrator
c) Universal testing machine (UTM)
d) Vicat apparatus
Discussion
Explanation: Core cutter is used to determine dry density of soil. Vibrator is used in sieve analysis. UTM can be used to test various parameters – tension, bending, shear of various materials. Vicat apparatus consists of a needle, used to penetrate the cement paste sample.
8. What is the initial setting time of cement?
a) 1 hour
b) 30 minutes
c) 15 minutes
d) 30 hours
Discussion
Explanation: As per IS code 4031-part 5, the initial setting time of cement is minimum of 30 minutes. After this cement will start losing its plasticity and will not be workable.
9. Use of coarser cement particles leads to:
a) Low durability
b) Higher strength
c) Low consistency
d) Higher soundness
Discussion
Explanation: For coarser particles, hydration starts on the surface of particles, hence, it might not be completely hydrated. This causes low strength and low durability.
10. Green cement is:
a) Green coloured cement
b) Cement mixed with plant products
c) Cement mixed with recycled materials
d) Cement mixed with green algae
Discussion
Explanation: Green cement is a cementitious material which employs the use of optimized recycled materials. These can meet or even exceed the functional performance of Portland cement.