AK Concrete Contractor Exam Questions
and Correct Answers (Verified Answers)
Plus Rationale 2027 Q&A| Instant
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1. What is the primary purpose of Portland cement in a concrete
mixture?
a. To provide color
b. To reduce aggregate size
c. To bind the aggregates together
d. To prevent all cracking
Rationale: Portland cement reacts chemically with water through
hydration to form cementitious compounds that bind the fine and
coarse aggregates into a hardened concrete mass.
2. Which ingredient generally makes up the largest volume of a
conventional concrete mixture?
,a. Cement
b. Water
c. Admixtures
d. Aggregate
Rationale: Fine and coarse aggregates commonly constitute most of the
concrete volume. They provide dimensional stability, reduce shrinkage,
and contribute significantly to the strength and economy of the mixture.
3. What is the water-cement ratio?
a. The ratio of aggregate weight to cement weight
b. The ratio of water volume to aggregate volume
c. The ratio of the weight of water to the weight of cementitious
material
d. The ratio of cement volume to total concrete volume
Rationale: The water-cement ratio compares the mass of mixing water
with the mass of cementitious material. Controlling this ratio is critical
because excessive water generally reduces strength and durability.
4. What is the primary effect of adding excessive water to fresh
concrete?
a. It always increases durability
b. It eliminates shrinkage
,c. It increases cement content
d. It generally reduces strength and durability
Rationale: Excess water increases the amount of capillary pore space
left after hydration. This can reduce compressive strength and increase
permeability, shrinkage, and susceptibility to deterioration.
5. What does concrete slump primarily measure?
a. Compressive strength
b. Air content
c. Consistency and workability of fresh concrete
d. Aggregate hardness
Rationale: The slump test provides an indication of the consistency of
freshly mixed concrete. It does not directly measure compressive
strength, although an unusually high slump caused by added water can
affect strength.
6. What is the main purpose of reinforcing steel in reinforced
concrete?
a. To make concrete waterproof
b. To eliminate curing
c. To resist tensile stresses
d. To replace coarse aggregate
, Rationale: Concrete performs very well in compression but is
comparatively weak in tension. Reinforcing steel is placed strategically
to resist tensile forces and control cracking.
7. What is concrete curing?
a. Removing forms immediately after placement
b. Adding aggregate after finishing
c. Maintaining suitable moisture and temperature conditions so
hydration can continue
d. Increasing the water-cement ratio after placement
Rationale: Proper curing allows cement hydration to continue and helps
concrete develop its intended strength and durability. Inadequate curing
can result in a weaker and more permeable surface.
8. Why is concrete consolidation performed?
a. To increase the water content
b. To cool the concrete
c. To remove trapped air and ensure proper contact around
reinforcement and forms
d. To stop cement hydration
and Correct Answers (Verified Answers)
Plus Rationale 2027 Q&A| Instant
Download Pdf
1. What is the primary purpose of Portland cement in a concrete
mixture?
a. To provide color
b. To reduce aggregate size
c. To bind the aggregates together
d. To prevent all cracking
Rationale: Portland cement reacts chemically with water through
hydration to form cementitious compounds that bind the fine and
coarse aggregates into a hardened concrete mass.
2. Which ingredient generally makes up the largest volume of a
conventional concrete mixture?
,a. Cement
b. Water
c. Admixtures
d. Aggregate
Rationale: Fine and coarse aggregates commonly constitute most of the
concrete volume. They provide dimensional stability, reduce shrinkage,
and contribute significantly to the strength and economy of the mixture.
3. What is the water-cement ratio?
a. The ratio of aggregate weight to cement weight
b. The ratio of water volume to aggregate volume
c. The ratio of the weight of water to the weight of cementitious
material
d. The ratio of cement volume to total concrete volume
Rationale: The water-cement ratio compares the mass of mixing water
with the mass of cementitious material. Controlling this ratio is critical
because excessive water generally reduces strength and durability.
4. What is the primary effect of adding excessive water to fresh
concrete?
a. It always increases durability
b. It eliminates shrinkage
,c. It increases cement content
d. It generally reduces strength and durability
Rationale: Excess water increases the amount of capillary pore space
left after hydration. This can reduce compressive strength and increase
permeability, shrinkage, and susceptibility to deterioration.
5. What does concrete slump primarily measure?
a. Compressive strength
b. Air content
c. Consistency and workability of fresh concrete
d. Aggregate hardness
Rationale: The slump test provides an indication of the consistency of
freshly mixed concrete. It does not directly measure compressive
strength, although an unusually high slump caused by added water can
affect strength.
6. What is the main purpose of reinforcing steel in reinforced
concrete?
a. To make concrete waterproof
b. To eliminate curing
c. To resist tensile stresses
d. To replace coarse aggregate
, Rationale: Concrete performs very well in compression but is
comparatively weak in tension. Reinforcing steel is placed strategically
to resist tensile forces and control cracking.
7. What is concrete curing?
a. Removing forms immediately after placement
b. Adding aggregate after finishing
c. Maintaining suitable moisture and temperature conditions so
hydration can continue
d. Increasing the water-cement ratio after placement
Rationale: Proper curing allows cement hydration to continue and helps
concrete develop its intended strength and durability. Inadequate curing
can result in a weaker and more permeable surface.
8. Why is concrete consolidation performed?
a. To increase the water content
b. To cool the concrete
c. To remove trapped air and ensure proper contact around
reinforcement and forms
d. To stop cement hydration
