1. Which of the following has the highest compressive strength?
A) Brick
B) Cement mortar
C) Concrete
D) Steel
Answer: D) Steel
Steel has the highest compressive and tensile strength among common construction materials.
2. Which test is used to determine the workability of concrete?
A) Vicat test
B) Slump test
C) Compaction factor test
D) Impact test
Answer: B) Slump test
The slump test measures how easily freshly mixed concrete can flow.
3. The minimum water-cement ratio required for hydration is approximately:
A) 0.15
B) 0.25
C) 0.35
D) 0.45
Answer: B) 0.25
A ratio of about 0.25 is needed for complete hydration, though 0.4–0.5 is used for better workability.
4. Which of the following is a non-destructive test for concrete?
A) Slump test
B) Cube test
C) Rebound hammer test
D) Compaction factor test
Answer: C) Rebound hammer test
This test estimates surface hardness and strength without damaging the concrete.
5. The process of removing air bubbles from freshly placed concrete is called:
A) Mixing
B) Curing
C) Compacting
D) Setting
Answer: C) Compacting
Compaction ensures dense concrete and prevents honeycombing.
6. The main cause of spalling in concrete is:
A) Over-curing
B) Excessive heat
C) Corrosion of reinforcement
D) Low water-cement ratio
Answer: C) Corrosion of reinforcement
Corrosion causes expansion of steel, leading to cracking and spalling.
7. The main constituent responsible for the strength of cement is:
A) Lime
B) Silica
C) Alumina
D) Iron oxide
Answer: A) Lime
Lime (CaO) provides strength and hardness to cement.
8. The initial setting time of ordinary Portland cement should not be less than:
A) 10 minutes
B) 30 minutes
C) 45 minutes
D) 60 minutes
Answer: B) 30 minutes
According to IS 4031, the initial setting time should be at least 30 minutes.
9. The bearing capacity of soil depends primarily on:
A) Moisture content
B) Grain size
C) Density and type of soil
D) All of the above
Answer: D) All of the above
All these factors influence how much load soil can safely support.
10. The main purpose of curing concrete is to:
A) Reduce heat of hydration
B) Prevent shrinkage
C) Maintain moisture for hydration
D) Increase workability
Answer: C) Maintain moisture for hydration
Curing ensures sufficient moisture is available for complete cement hydration, improving strength and durability.