AK CONCRETE CONTRACTOR EXAM QUESTIONS
AND CORRECT ANSWERS (VERIFIED ANSWERS)
Q&A 2027 |INSTANT DOWNLOAD PDF
1. What is the primary purpose of Portland cement in
concrete?
A. To provide color
B. To act as the coarse aggregate
C. To bind the aggregate together
D. To increase air temperature
Correct answer: C. To bind the aggregate together
Rationale: Cement reacts with water through hydration and
forms the paste that binds aggregates into a solid mass.
2. Which ingredient generally makes up the largest volume of
conventional concrete?
A. Cement
B. Water
C. Aggregate
D. Admixture
Correct answer: C. Aggregate
Rationale: Fine and coarse aggregates commonly constitute
most of concrete's volume and provide dimensional stability.
3. What is the water-cement ratio?
,A. Ratio of aggregate to cement
B. Ratio of water to cement by weight
C. Ratio of cement to sand by volume
D. Ratio of water to aggregate
Correct answer: B. Ratio of water to cement by weight
Rationale: The water-cement ratio is a major factor affecting
concrete strength, durability, and permeability.
4. What generally happens when excessive water is added to a
concrete mix?
A. Strength usually increases
B. Permeability usually decreases
C. Strength and durability may decrease
D. Hydration stops immediately
Correct answer: C. Strength and durability may decrease
Rationale: Excess water can increase porosity after
evaporation, reducing strength and increasing permeability.
5. What is hydration in concrete?
A. Drying of aggregate
B. Chemical reaction between cement and water
C. Removal of cement paste
D. Compaction of soil
Correct answer: B. Chemical reaction between cement and
water
Rationale: Cement compounds chemically react with water,
producing hydration products that cause concrete to harden.
,6. What is the main purpose of coarse aggregate?
A. Provide bulk and structural stability
B. Replace all cement
C. Prevent hydration
D. Increase water content
Correct answer: A. Provide bulk and structural stability
Rationale: Coarse aggregate forms the structural skeleton of
concrete and reduces the amount of cement paste required.
7. What is fine aggregate commonly known as?
A. Gravel
B. Sand
C. Cement
D. Slag
Correct answer: B. Sand
Rationale: Fine aggregate generally consists of particles passing
the applicable sieve used to distinguish it from coarse
aggregate.
8. What is the purpose of an air-entraining admixture?
A. Eliminate all air from concrete
B. Create controlled microscopic air voids
C. Replace aggregate
D. Prevent cement hydration
, Correct answer: B. Create controlled microscopic air voids
Rationale: Entrained air can improve resistance to freeze-thaw
cycles, which is particularly important in cold climates.
9. What does concrete slump primarily measure?
A. Compressive strength
B. Cement content
C. Consistency or workability
D. Aggregate density
Correct answer: C. Consistency or workability
Rationale: The slump test provides an indication of fresh
concrete consistency and is not a direct strength test.
10. What instrument is used for a standard concrete slump
test?
A. Pressure gauge
B. Slump cone
C. Proctor mold
D. Compression cylinder
Correct answer: B. Slump cone
Rationale: Fresh concrete is placed and compacted in a
standardized slump cone, which is then lifted to measure the
resulting subsidence.
11. Why is concrete consolidated after placement?
A. To introduce large voids
B. To remove entrapped air and improve contact with forms
AND CORRECT ANSWERS (VERIFIED ANSWERS)
Q&A 2027 |INSTANT DOWNLOAD PDF
1. What is the primary purpose of Portland cement in
concrete?
A. To provide color
B. To act as the coarse aggregate
C. To bind the aggregate together
D. To increase air temperature
Correct answer: C. To bind the aggregate together
Rationale: Cement reacts with water through hydration and
forms the paste that binds aggregates into a solid mass.
2. Which ingredient generally makes up the largest volume of
conventional concrete?
A. Cement
B. Water
C. Aggregate
D. Admixture
Correct answer: C. Aggregate
Rationale: Fine and coarse aggregates commonly constitute
most of concrete's volume and provide dimensional stability.
3. What is the water-cement ratio?
,A. Ratio of aggregate to cement
B. Ratio of water to cement by weight
C. Ratio of cement to sand by volume
D. Ratio of water to aggregate
Correct answer: B. Ratio of water to cement by weight
Rationale: The water-cement ratio is a major factor affecting
concrete strength, durability, and permeability.
4. What generally happens when excessive water is added to a
concrete mix?
A. Strength usually increases
B. Permeability usually decreases
C. Strength and durability may decrease
D. Hydration stops immediately
Correct answer: C. Strength and durability may decrease
Rationale: Excess water can increase porosity after
evaporation, reducing strength and increasing permeability.
5. What is hydration in concrete?
A. Drying of aggregate
B. Chemical reaction between cement and water
C. Removal of cement paste
D. Compaction of soil
Correct answer: B. Chemical reaction between cement and
water
Rationale: Cement compounds chemically react with water,
producing hydration products that cause concrete to harden.
,6. What is the main purpose of coarse aggregate?
A. Provide bulk and structural stability
B. Replace all cement
C. Prevent hydration
D. Increase water content
Correct answer: A. Provide bulk and structural stability
Rationale: Coarse aggregate forms the structural skeleton of
concrete and reduces the amount of cement paste required.
7. What is fine aggregate commonly known as?
A. Gravel
B. Sand
C. Cement
D. Slag
Correct answer: B. Sand
Rationale: Fine aggregate generally consists of particles passing
the applicable sieve used to distinguish it from coarse
aggregate.
8. What is the purpose of an air-entraining admixture?
A. Eliminate all air from concrete
B. Create controlled microscopic air voids
C. Replace aggregate
D. Prevent cement hydration
, Correct answer: B. Create controlled microscopic air voids
Rationale: Entrained air can improve resistance to freeze-thaw
cycles, which is particularly important in cold climates.
9. What does concrete slump primarily measure?
A. Compressive strength
B. Cement content
C. Consistency or workability
D. Aggregate density
Correct answer: C. Consistency or workability
Rationale: The slump test provides an indication of fresh
concrete consistency and is not a direct strength test.
10. What instrument is used for a standard concrete slump
test?
A. Pressure gauge
B. Slump cone
C. Proctor mold
D. Compression cylinder
Correct answer: B. Slump cone
Rationale: Fresh concrete is placed and compacted in a
standardized slump cone, which is then lifted to measure the
resulting subsidence.
11. Why is concrete consolidated after placement?
A. To introduce large voids
B. To remove entrapped air and improve contact with forms
