AL CC Concrete Construction Contractor Exam
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1. What is the primary purpose of properly proportioning a concrete
mix?
a. To eliminate the need for curing
b. To increase the amount of mixing water
c. To achieve the required strength, workability, durability, and
economy
d. To prevent aggregate from being used
Rationale: Concrete mix proportioning balances cementitious materials,
water, aggregates, and admixtures to produce concrete with the
required performance characteristics. Proper proportions help achieve
strength and durability while maintaining workable concrete at a
reasonable cost.
, 2. Which material primarily acts as the binding agent in ordinary
Portland cement concrete?
a. Fine aggregate
b. Coarse aggregate
c. Water
d. Cement paste
Rationale: Cement reacts chemically with water through hydration and
forms a hardened paste that binds the aggregate particles together.
The aggregate provides most of the concrete's volume, but the cement
paste provides the bonding matrix.
3. What is the water-cement ratio most directly associated with?
a. Aggregate size only
b. Concrete color
c. Concrete strength and durability
d. Formwork dimensions
Rationale: The water-cement ratio strongly affects the porosity of
hardened cement paste. In general, reducing unnecessary water
improves strength and durability, provided the concrete remains
sufficiently workable for placement.
4. What is the main purpose of coarse aggregate in concrete?
,a. To provide hydration water
b. To chemically cure cement
c. To provide bulk, stability, and reduce the amount of cement paste
required
d. To replace all cement
Rationale: Coarse aggregate makes up a substantial portion of concrete
volume. Properly graded aggregate improves dimensional stability and
economy while reducing the quantity of cement paste needed.
5. What is the term for the chemical reaction between cement and
water?
a. Carbonation
b. Evaporation
c. Segregation
d. Hydration
Rationale: Hydration is the chemical reaction between cement
compounds and water. It produces hydration products that cause
cement paste to stiffen and eventually harden.
6. What is the primary purpose of concrete slump testing?
a. To determine compressive strength directly
b. To measure aggregate density
, c. To evaluate the consistency and workability of fresh concrete
d. To determine cement fineness
Rationale: A slump test measures the change in height of a fresh
concrete sample after the slump cone is removed. It provides an
indication of consistency and workability, although it is not a direct
measure of compressive strength.
7. Excessive water added to a concrete mixture at the jobsite can
generally:
a. Increase long-term durability
b. Eliminate shrinkage
c. Reduce strength and increase permeability
d. Eliminate the need for curing
Rationale: Additional water increases the water-cement ratio and can
leave more capillary pores after the concrete hardens. This commonly
reduces strength and durability and may increase shrinkage and
permeability.
8. Which aggregate is normally classified as fine aggregate?
a. Gravel retained on a large sieve
b. Crushed stone larger than 1 inch
Questions and Correct Answers (Verified
Answers) Plus Rationale 2027 Q&A| Instant
Download Pdf
1. What is the primary purpose of properly proportioning a concrete
mix?
a. To eliminate the need for curing
b. To increase the amount of mixing water
c. To achieve the required strength, workability, durability, and
economy
d. To prevent aggregate from being used
Rationale: Concrete mix proportioning balances cementitious materials,
water, aggregates, and admixtures to produce concrete with the
required performance characteristics. Proper proportions help achieve
strength and durability while maintaining workable concrete at a
reasonable cost.
, 2. Which material primarily acts as the binding agent in ordinary
Portland cement concrete?
a. Fine aggregate
b. Coarse aggregate
c. Water
d. Cement paste
Rationale: Cement reacts chemically with water through hydration and
forms a hardened paste that binds the aggregate particles together.
The aggregate provides most of the concrete's volume, but the cement
paste provides the bonding matrix.
3. What is the water-cement ratio most directly associated with?
a. Aggregate size only
b. Concrete color
c. Concrete strength and durability
d. Formwork dimensions
Rationale: The water-cement ratio strongly affects the porosity of
hardened cement paste. In general, reducing unnecessary water
improves strength and durability, provided the concrete remains
sufficiently workable for placement.
4. What is the main purpose of coarse aggregate in concrete?
,a. To provide hydration water
b. To chemically cure cement
c. To provide bulk, stability, and reduce the amount of cement paste
required
d. To replace all cement
Rationale: Coarse aggregate makes up a substantial portion of concrete
volume. Properly graded aggregate improves dimensional stability and
economy while reducing the quantity of cement paste needed.
5. What is the term for the chemical reaction between cement and
water?
a. Carbonation
b. Evaporation
c. Segregation
d. Hydration
Rationale: Hydration is the chemical reaction between cement
compounds and water. It produces hydration products that cause
cement paste to stiffen and eventually harden.
6. What is the primary purpose of concrete slump testing?
a. To determine compressive strength directly
b. To measure aggregate density
, c. To evaluate the consistency and workability of fresh concrete
d. To determine cement fineness
Rationale: A slump test measures the change in height of a fresh
concrete sample after the slump cone is removed. It provides an
indication of consistency and workability, although it is not a direct
measure of compressive strength.
7. Excessive water added to a concrete mixture at the jobsite can
generally:
a. Increase long-term durability
b. Eliminate shrinkage
c. Reduce strength and increase permeability
d. Eliminate the need for curing
Rationale: Additional water increases the water-cement ratio and can
leave more capillary pores after the concrete hardens. This commonly
reduces strength and durability and may increase shrinkage and
permeability.
8. Which aggregate is normally classified as fine aggregate?
a. Gravel retained on a large sieve
b. Crushed stone larger than 1 inch
