1. In cement hardening process ___________ instants are very important.
a) 1
b) 2
c) 3
d) 4
Explanation: In cement hardening process, two instants are very important, i.e. initial setting and final setting.
2. What is the initial setting time?
a) The time at which cement paste loses its plasticity
b) The time at which cement paste loses its elasticity
c) The time at which cement paste gains its plasticity
d) The time at which cement paste gains its elasticity
Explanation: The time at which cement paste loses its plasticity is known as initial setting time of the concrete.
3. Initial setting time of OPC should not be less than ___________
a) 15 minutes
b) 30 minutes
c) 28 minutes
d) 1 hour
Explanation: As per IS specification, the minimum initial setting time is 30 minutes for ordinary portland cement.
4. Final setting time of cement should not be more than _______
a) 1 hour
b) 2 hours
c) 5 hours
d) 10 hours
Explanation: As per IS specification, the maximum final setting time for all type of cement is 10 hours.
5. In the soundness test, the whole assembly is immersed in water for _______
a) 30 minutes
b) 1 hour
c) 24 hours
d) 48 hours
Explanation: Submerge the whole assembly immediately in water at a temperature of 27oC ± 2oC and keep it there for 24 hour for better results.
6. What is the final setting time?
a) The time at which cement paste loses its plasticity
b) The time to reach that stage at which cement paste loses its elasticity
c) The time at which cement paste gains its plasticity
d) The time when cement paste becomes hardened
Explanation: The final setting is defined as the time taken to reach the cement paste to become into a hardened mass.
7. Initial setting time of Low Heat Cement should not be less than _____________.
a) 15 minutes
b) 30 minutes
c) 60 minutes
d) 1 hour
Explanation: As per IS specification, the minimum initial setting time is 60 minutes for low heat cement.
8. If t1=Time at which water is first added to cement, t2=Time when needle fails to penetrate 5 mm to 7 mm from bottom of the mould, t3=Time when the needle makes an impression but the attachment fails to do so, then what is initial setting time?
a) t2-t1
b) t2+t1
c) t3-t1
d) 2*t1
Explanation: t2-t1 is the formula to determine the value of the initial setting time of concrete for further process.
9. If t1=Time at which water is first added to cement, t2=Time when needle fails to penetrate 5 mm to 7 mm from bottom of the mould, t3=Time when the needle makes an impression but the attachment fails to do so, then what is final setting time?
a) t2-t1
b) t2+t1
c) t3-t1
d) 2*t1
Explanation: t3-t1 is the formula to determine the value of the final setting time of concrete for further process.
10. What is the capacity of a measuring cylinder?
a) 10ml
b) 50ml
c) 100ml
d) 1000ml
Explanation: The capacity of the measuring cylinder is 100 ml with the least count of 1 ml for the setting time test.