CSLB-CONTRACTOR EXAMINATION (C-8)
QUESTIONS AND CORRECT ANSWERS (VERIFIED
ANSWER) 2027|INSTANT DOWNLOAD PDF
1. What is the primary purpose of a concrete mix design?
A. To eliminate curing
B. To determine suitable proportions of cementitious materials,
water, aggregates, and admixtures
C. To prevent all cracking
D. To eliminate reinforcement
Correct answer: B. To determine suitable proportions of
cementitious materials, water, aggregates, and admixtures
Rationale: A mix design establishes proportions needed to
achieve the required strength, workability, durability, and other
performance characteristics.
2. Which ingredient primarily acts as the binder in
conventional concrete?
A. Coarse aggregate
B. Fine aggregate
C. Portland cement
D. Water
Correct answer: C. Portland cement
Rationale: Cement reacts chemically with water through
hydration and binds the aggregate particles together.
,3. What is the main function of water in a concrete mixture?
A. Only to cool the concrete
B. To hydrate cement and provide workability
C. To increase aggregate size
D. To prevent hydration
Correct answer: B. To hydrate cement and provide workability
Rationale: Water is necessary for cement hydration and
contributes to the workability of fresh concrete.
4. Which aggregate generally has the largest particle size?
A. Cement
B. Fine aggregate
C. Coarse aggregate
D. Mineral admixture
Correct answer: C. Coarse aggregate
Rationale: Coarse aggregate typically consists of gravel or
crushed stone retained on the applicable sieve.
5. What is the water-cement ratio?
A. Ratio of aggregate to cement
B. Ratio of water to cementitious material by weight
C. Ratio of sand to gravel
D. Ratio of cement to air
,Correct answer: B. Ratio of water to cementitious material by
weight
Rationale: The water-cementitious materials ratio is a major
factor affecting concrete strength and durability.
6. Increasing the water-cement ratio generally has what effect
on concrete strength?
A. Increases strength indefinitely
B. Generally decreases strength
C. Has no effect
D. Converts concrete into mortar
Correct answer: B. Generally decreases strength
Rationale: Excess water can leave additional capillary pores
after evaporation, reducing strength and durability.
7. What is the purpose of a concrete slump test?
A. Measure compressive strength directly
B. Determine cement fineness
C. Evaluate consistency or workability of fresh concrete
D. Measure aggregate density only
Correct answer: C. Evaluate consistency or workability of fresh
concrete
Rationale: The slump test provides an indication of the
consistency of freshly mixed concrete.
, 8. Which tool is commonly used to perform a slump test?
A. Proctor mold
B. Slump cone
C. Compression machine
D. Transit level
Correct answer: B. Slump cone
Rationale: A standard slump cone is filled and consolidated
according to the applicable testing procedure.
9. What does concrete hydration refer to?
A. Evaporation of all water
B. Chemical reactions between cement and water
C. Mixing aggregate with sand
D. Freezing concrete
Correct answer: B. Chemical reactions between cement and
water
Rationale: Hydration is the chemical process through which
cement reacts with water and develops binding properties.
10. Why is curing concrete important?
A. It removes all moisture immediately
B. It promotes continued hydration and strength development
QUESTIONS AND CORRECT ANSWERS (VERIFIED
ANSWER) 2027|INSTANT DOWNLOAD PDF
1. What is the primary purpose of a concrete mix design?
A. To eliminate curing
B. To determine suitable proportions of cementitious materials,
water, aggregates, and admixtures
C. To prevent all cracking
D. To eliminate reinforcement
Correct answer: B. To determine suitable proportions of
cementitious materials, water, aggregates, and admixtures
Rationale: A mix design establishes proportions needed to
achieve the required strength, workability, durability, and other
performance characteristics.
2. Which ingredient primarily acts as the binder in
conventional concrete?
A. Coarse aggregate
B. Fine aggregate
C. Portland cement
D. Water
Correct answer: C. Portland cement
Rationale: Cement reacts chemically with water through
hydration and binds the aggregate particles together.
,3. What is the main function of water in a concrete mixture?
A. Only to cool the concrete
B. To hydrate cement and provide workability
C. To increase aggregate size
D. To prevent hydration
Correct answer: B. To hydrate cement and provide workability
Rationale: Water is necessary for cement hydration and
contributes to the workability of fresh concrete.
4. Which aggregate generally has the largest particle size?
A. Cement
B. Fine aggregate
C. Coarse aggregate
D. Mineral admixture
Correct answer: C. Coarse aggregate
Rationale: Coarse aggregate typically consists of gravel or
crushed stone retained on the applicable sieve.
5. What is the water-cement ratio?
A. Ratio of aggregate to cement
B. Ratio of water to cementitious material by weight
C. Ratio of sand to gravel
D. Ratio of cement to air
,Correct answer: B. Ratio of water to cementitious material by
weight
Rationale: The water-cementitious materials ratio is a major
factor affecting concrete strength and durability.
6. Increasing the water-cement ratio generally has what effect
on concrete strength?
A. Increases strength indefinitely
B. Generally decreases strength
C. Has no effect
D. Converts concrete into mortar
Correct answer: B. Generally decreases strength
Rationale: Excess water can leave additional capillary pores
after evaporation, reducing strength and durability.
7. What is the purpose of a concrete slump test?
A. Measure compressive strength directly
B. Determine cement fineness
C. Evaluate consistency or workability of fresh concrete
D. Measure aggregate density only
Correct answer: C. Evaluate consistency or workability of fresh
concrete
Rationale: The slump test provides an indication of the
consistency of freshly mixed concrete.
, 8. Which tool is commonly used to perform a slump test?
A. Proctor mold
B. Slump cone
C. Compression machine
D. Transit level
Correct answer: B. Slump cone
Rationale: A standard slump cone is filled and consolidated
according to the applicable testing procedure.
9. What does concrete hydration refer to?
A. Evaporation of all water
B. Chemical reactions between cement and water
C. Mixing aggregate with sand
D. Freezing concrete
Correct answer: B. Chemical reactions between cement and
water
Rationale: Hydration is the chemical process through which
cement reacts with water and develops binding properties.
10. Why is curing concrete important?
A. It removes all moisture immediately
B. It promotes continued hydration and strength development
