DM G+1 EXAM | 200 QUESTIONS | WITH COMPLETE
VERIFIED ANSWERS AND DETAILED RATIONALE
Question 1
The minimum grade of concrete recommended for reinforced concrete
work in general building construction is:
A) M10
B) M15
C) M20
D) M25
E) M30
Correct Answer: C) M20
Rationale: As per IS 456:2000, the minimum grade of concrete for
reinforced concrete work is M20. This ensures adequate strength and
durability for structural members in buildings.
Question 2
The initial setting time of Ordinary Portland Cement should not be less
than:
A) 15 minutes
B) 30 minutes
C) 45 minutes
D) 60 minutes
E) 90 minutes
,Correct Answer: B) 30 minutes
Rationale: The initial setting time of OPC is a minimum of 30 minutes as
per IS 4031. This allows sufficient time for mixing, transporting, and
placing the concrete before it begins to harden.
Question 3
What is the maximum free fall height for concrete placement without
segregation?
A) 0.5 m
B) 1.0 m
C) 1.5 m
D) 2.0 m
E) 2.5 m
Correct Answer: C) 1.5 m
Rationale: Concrete should not be dropped from a height exceeding 1.5
meters to prevent segregation of aggregates from the cement paste,
which would weaken the structure.
Question 4
The characteristic compressive strength of concrete is defined as the
strength below which not more than what percentage of test results are
expected to fall?
A) 2%
B) 5%
C) 10%
D) 15%
E) 20%
,Correct Answer: B) 5%
Rationale: Characteristic strength (fck) is the value below which not
more than 5% of test results are expected to fall. This statistical
definition ensures structural safety standards.
Question 5
Which of the following is NOT a property of good brick?
A) Uniform shape and size
B) High thermal conductivity
C) Low water absorption
D) Good compressive strength
E) Free from cracks
Correct Answer: B) High thermal conductivity
Rationale: Good bricks should have low thermal conductivity to provide
insulation. High thermal conductivity would allow heat transfer, making
buildings uncomfortable in hot climates.
Question 6
The minimum cover for reinforced concrete columns as per IS 456 is:
A) 20 mm
B) 25 mm
C) 30 mm
D) 40 mm
E) 50 mm
Correct Answer: D) 40 mm
Rationale: The minimum clear cover for columns is 40 mm to protect
, reinforcement from corrosion and fire. This is greater than for beams
and slabs due to the critical nature of column failure.
Question 7
A slump test is used to measure the:
A) Strength of concrete
B) Workability of concrete
C) Durability of concrete
D) Permeability of concrete
E) Density of concrete
Correct Answer: B) Workability of concrete
Rationale: The slump test measures the consistency and workability of
fresh concrete. It indicates how easily concrete flows and is placed, with
higher slump values indicating more workable concrete.
Question 8
The maximum water-cement ratio for moderate exposure conditions as
per IS 456 is:
A) 0.35
B) 0.40
C) 0.45
D) 0.50
E) 0.55
Correct Answer: D) 0.50
Rationale: For moderate exposure conditions, the maximum water-
VERIFIED ANSWERS AND DETAILED RATIONALE
Question 1
The minimum grade of concrete recommended for reinforced concrete
work in general building construction is:
A) M10
B) M15
C) M20
D) M25
E) M30
Correct Answer: C) M20
Rationale: As per IS 456:2000, the minimum grade of concrete for
reinforced concrete work is M20. This ensures adequate strength and
durability for structural members in buildings.
Question 2
The initial setting time of Ordinary Portland Cement should not be less
than:
A) 15 minutes
B) 30 minutes
C) 45 minutes
D) 60 minutes
E) 90 minutes
,Correct Answer: B) 30 minutes
Rationale: The initial setting time of OPC is a minimum of 30 minutes as
per IS 4031. This allows sufficient time for mixing, transporting, and
placing the concrete before it begins to harden.
Question 3
What is the maximum free fall height for concrete placement without
segregation?
A) 0.5 m
B) 1.0 m
C) 1.5 m
D) 2.0 m
E) 2.5 m
Correct Answer: C) 1.5 m
Rationale: Concrete should not be dropped from a height exceeding 1.5
meters to prevent segregation of aggregates from the cement paste,
which would weaken the structure.
Question 4
The characteristic compressive strength of concrete is defined as the
strength below which not more than what percentage of test results are
expected to fall?
A) 2%
B) 5%
C) 10%
D) 15%
E) 20%
,Correct Answer: B) 5%
Rationale: Characteristic strength (fck) is the value below which not
more than 5% of test results are expected to fall. This statistical
definition ensures structural safety standards.
Question 5
Which of the following is NOT a property of good brick?
A) Uniform shape and size
B) High thermal conductivity
C) Low water absorption
D) Good compressive strength
E) Free from cracks
Correct Answer: B) High thermal conductivity
Rationale: Good bricks should have low thermal conductivity to provide
insulation. High thermal conductivity would allow heat transfer, making
buildings uncomfortable in hot climates.
Question 6
The minimum cover for reinforced concrete columns as per IS 456 is:
A) 20 mm
B) 25 mm
C) 30 mm
D) 40 mm
E) 50 mm
Correct Answer: D) 40 mm
Rationale: The minimum clear cover for columns is 40 mm to protect
, reinforcement from corrosion and fire. This is greater than for beams
and slabs due to the critical nature of column failure.
Question 7
A slump test is used to measure the:
A) Strength of concrete
B) Workability of concrete
C) Durability of concrete
D) Permeability of concrete
E) Density of concrete
Correct Answer: B) Workability of concrete
Rationale: The slump test measures the consistency and workability of
fresh concrete. It indicates how easily concrete flows and is placed, with
higher slump values indicating more workable concrete.
Question 8
The maximum water-cement ratio for moderate exposure conditions as
per IS 456 is:
A) 0.35
B) 0.40
C) 0.45
D) 0.50
E) 0.55
Correct Answer: D) 0.50
Rationale: For moderate exposure conditions, the maximum water-
