NRMCA Concrete Technologist Level 2
Certification Exam Practice Questions and
Verified Answers with Detailed Rationales
(2026 Edition)
What is the primary function of Portland cement in concrete?
A. To provide aggregate volume
B. To act as the binding material
C. To prevent all cracking
D. To increase aggregate absorption
Correct Answer: B. To act as the binding material
Rationale: Portland cement reacts chemically with water during hydration and
forms cementitious products that bind the aggregate particles into a hardened
concrete mass.
Which property of aggregate has a major effect on concrete workability?
A. Color
B. Particle shape and surface texture
C. Mineral color
D. Electrical conductivity
Correct Answer: B. Particle shape and surface texture
Rationale: Rounded, smooth aggregates generally require less paste for a given
workability, whereas angular and rough-textured particles increase internal
friction and can reduce workability.
What does the water-cementitious materials ratio primarily influence?
A. Concrete color
B. Concrete strength and permeability
,C. Aggregate mineralogy
D. Form dimensions
Correct Answer: B. Concrete strength and permeability
Rationale: For a given set of materials and adequate curing, reducing the water-
to-cementitious-materials ratio generally produces a denser paste with higher
strength and lower permeability.
What is the primary purpose of an air-entraining admixture?
A. To eliminate cement hydration
B. To improve resistance to freezing and thawing
C. To increase aggregate size
D. To eliminate curing
Correct Answer: B. To improve resistance to freezing and thawing
Rationale: Air-entraining admixtures create a system of small, distributed air voids
that provides pressure-relief space when water freezes within concrete.
The fineness modulus of an aggregate is primarily an indication of:
A. Aggregate color
B. Aggregate gradation or relative coarseness
C. Aggregate absorption alone
D. Cement content
Correct Answer: B. Aggregate gradation or relative coarseness
Rationale: Fineness modulus is an empirical index calculated from sieve-analysis
results. A higher value generally indicates a coarser aggregate.
Which material is considered a supplementary cementitious material?
A. Fly ash
B. Coarse aggregate
C. Mixing water
D. Reinforcing steel
_Correct Answer: A. Fly ash
,Rationale: Fly ash is a supplementary cementitious material that can contribute to
concrete properties such as strength development, workability, and durability.
What is the purpose of controlling aggregate moisture before batching concrete?
A. To determine cement color
B. To adjust aggregate quantities and batch water
C. To eliminate aggregate testing
D. To increase aggregate size
_Correct Answer: B. To adjust aggregate quantities and batch water
Rationale: Aggregate moisture changes both the aggregate batch weight and the
amount of water entering the concrete. Moisture corrections help maintain the
intended mixture proportions.
Which aggregate moisture condition represents pores filled with water but no water
on the particle surface?
A. Oven-dry
B. Air-dry
C. Saturated surface-dry
D. Wet with free moisture
_Correct Answer: C. Saturated surface-dry
Rationale: In the saturated surface-dry condition, the aggregate pores are filled
with water while the particle surface contains no free water.
What does slump primarily measure?
A. Concrete compressive strength
B. Consistency of fresh concrete
C. Cement fineness
D. Aggregate absorption
_Correct Answer: B. Consistency of fresh concrete
Rationale: The slump test provides an indication of the consistency or relative
fluidity of fresh concrete. It does not directly measure strength.
, Which ASTM test method is commonly associated with the slump test?
A. ASTM C39
B. ASTM C143/C143M
C. ASTM C231
D. ASTM C1064/C1064M
_Correct Answer: B. ASTM C143/C143M
Rationale: ASTM C143/C143M covers the slump test for hydraulic-cement
concrete and is commonly used to evaluate fresh-concrete consistency.
Which test is commonly used to determine compressive strength of cylindrical
concrete specimens?
A. ASTM C39/C39M
B. ASTM C143/C143M
C. ASTM C231
D. ASTM C138/C138M
_Correct Answer: A. ASTM C39/C39M
Rationale: ASTM C39/C39M covers the determination of compressive strength of
cylindrical concrete specimens.
Which test method is associated with determining air content of freshly mixed
concrete using the pressure method?
A. ASTM C39
B. ASTM C143
C. ASTM C231
D. ASTM C78
_Correct Answer: C. ASTM C231
Rationale: ASTM C231 covers the pressure method for determining air content of
freshly mixed concrete containing relatively dense aggregate.
What is the primary purpose of determining concrete temperature during
production?
Certification Exam Practice Questions and
Verified Answers with Detailed Rationales
(2026 Edition)
What is the primary function of Portland cement in concrete?
A. To provide aggregate volume
B. To act as the binding material
C. To prevent all cracking
D. To increase aggregate absorption
Correct Answer: B. To act as the binding material
Rationale: Portland cement reacts chemically with water during hydration and
forms cementitious products that bind the aggregate particles into a hardened
concrete mass.
Which property of aggregate has a major effect on concrete workability?
A. Color
B. Particle shape and surface texture
C. Mineral color
D. Electrical conductivity
Correct Answer: B. Particle shape and surface texture
Rationale: Rounded, smooth aggregates generally require less paste for a given
workability, whereas angular and rough-textured particles increase internal
friction and can reduce workability.
What does the water-cementitious materials ratio primarily influence?
A. Concrete color
B. Concrete strength and permeability
,C. Aggregate mineralogy
D. Form dimensions
Correct Answer: B. Concrete strength and permeability
Rationale: For a given set of materials and adequate curing, reducing the water-
to-cementitious-materials ratio generally produces a denser paste with higher
strength and lower permeability.
What is the primary purpose of an air-entraining admixture?
A. To eliminate cement hydration
B. To improve resistance to freezing and thawing
C. To increase aggregate size
D. To eliminate curing
Correct Answer: B. To improve resistance to freezing and thawing
Rationale: Air-entraining admixtures create a system of small, distributed air voids
that provides pressure-relief space when water freezes within concrete.
The fineness modulus of an aggregate is primarily an indication of:
A. Aggregate color
B. Aggregate gradation or relative coarseness
C. Aggregate absorption alone
D. Cement content
Correct Answer: B. Aggregate gradation or relative coarseness
Rationale: Fineness modulus is an empirical index calculated from sieve-analysis
results. A higher value generally indicates a coarser aggregate.
Which material is considered a supplementary cementitious material?
A. Fly ash
B. Coarse aggregate
C. Mixing water
D. Reinforcing steel
_Correct Answer: A. Fly ash
,Rationale: Fly ash is a supplementary cementitious material that can contribute to
concrete properties such as strength development, workability, and durability.
What is the purpose of controlling aggregate moisture before batching concrete?
A. To determine cement color
B. To adjust aggregate quantities and batch water
C. To eliminate aggregate testing
D. To increase aggregate size
_Correct Answer: B. To adjust aggregate quantities and batch water
Rationale: Aggregate moisture changes both the aggregate batch weight and the
amount of water entering the concrete. Moisture corrections help maintain the
intended mixture proportions.
Which aggregate moisture condition represents pores filled with water but no water
on the particle surface?
A. Oven-dry
B. Air-dry
C. Saturated surface-dry
D. Wet with free moisture
_Correct Answer: C. Saturated surface-dry
Rationale: In the saturated surface-dry condition, the aggregate pores are filled
with water while the particle surface contains no free water.
What does slump primarily measure?
A. Concrete compressive strength
B. Consistency of fresh concrete
C. Cement fineness
D. Aggregate absorption
_Correct Answer: B. Consistency of fresh concrete
Rationale: The slump test provides an indication of the consistency or relative
fluidity of fresh concrete. It does not directly measure strength.
, Which ASTM test method is commonly associated with the slump test?
A. ASTM C39
B. ASTM C143/C143M
C. ASTM C231
D. ASTM C1064/C1064M
_Correct Answer: B. ASTM C143/C143M
Rationale: ASTM C143/C143M covers the slump test for hydraulic-cement
concrete and is commonly used to evaluate fresh-concrete consistency.
Which test is commonly used to determine compressive strength of cylindrical
concrete specimens?
A. ASTM C39/C39M
B. ASTM C143/C143M
C. ASTM C231
D. ASTM C138/C138M
_Correct Answer: A. ASTM C39/C39M
Rationale: ASTM C39/C39M covers the determination of compressive strength of
cylindrical concrete specimens.
Which test method is associated with determining air content of freshly mixed
concrete using the pressure method?
A. ASTM C39
B. ASTM C143
C. ASTM C231
D. ASTM C78
_Correct Answer: C. ASTM C231
Rationale: ASTM C231 covers the pressure method for determining air content of
freshly mixed concrete containing relatively dense aggregate.
What is the primary purpose of determining concrete temperature during
production?
