NRMCA CONCRETE TECHNOLOGIST LEVEL 2
CERTIFICATION EXAMINATION COMPLETE QUESTIONS
AND DETAILED SOLUTIONS LATEST UPDATE THIS YEAR
JUST RELEASED
1.
A concrete mixture has adequate compressive strength but repeatedly
shows excessive slump loss during transportation. Which factor should
be investigated first?
A. Aggregate color
B. Cement fineness only
C. Water demand, admixture compatibility, and temperature effects
D. Formwork dimensions
Answer: C
Rationale: Slump loss can result from temperature, hydration rate,
aggregate absorption, and interactions between cementitious materials
and chemical admixtures.
2.
When determining concrete yield from batch weights and measured
unit weight, which calculation provides the most appropriate estimate?
A. Total batch mass divided by measured unit weight
B. Cement mass divided by water mass
,C. Aggregate mass divided by cement content
D. Water mass multiplied by slump
Answer: A
Rationale: Concrete yield is calculated by dividing the total mass of
freshly batched materials by the measured unit weight of concrete.
3.
Why is maintaining a consistent water-cementitious materials ratio
particularly important when producing strength-controlled concrete
mixtures?
A. It controls aggregate color
B. It strongly influences strength, durability, permeability, and
consistency
C. It eliminates air entrainment
D. It determines cement storage capacity
Answer: B
Rationale: The water-to-cementitious-materials ratio substantially
affects hydration products, porosity, strength development,
permeability, and durability.
4.
A technician obtains significantly different slump results from two
samples taken from the same truck. What should be evaluated?
,A. Testing procedure, sampling location, and concrete uniformity
B. Cement bag labeling
C. Aggregate mineral color
D. Truck tire pressure
Answer: A
Rationale: Sampling and testing inconsistencies, segregation, discharge
timing, and batch nonuniformity can produce substantially different
slump measurements.
5.
What is the primary purpose of determining the moisture condition of
aggregates before batching concrete?
A. To determine cement color
B. To accurately calculate aggregate and mixing-water contributions
C. To increase aggregate size
D. To eliminate air entrainment
Answer: B
Rationale: Aggregate moisture directly changes both aggregate batch
weights and effective mixing water, influencing slump and water-
cementitious ratio.
6.
If aggregate contains free surface moisture exceeding its absorption
capacity, what happens to the concrete mixture?
, A. Aggregate contributes additional water to the mixture
B. Aggregate removes all mixing water
C. Cement content automatically increases
D. Air content becomes zero
Answer: A
Rationale: Surface moisture beyond aggregate absorption contributes
water to the concrete and must be included when adjusting batch
water.
7.
Which aggregate condition represents saturated surface-dry material?
A. Completely dry pores and dry surface
B. Pores filled with water while the external surface remains dry
C. Completely submerged aggregate
D. Aggregate containing visible free surface water
Answer: B
Rationale: Saturated surface-dry aggregate has its internal pores filled
while no free water remains on the particle surface.
8.
What is the principal purpose of an air-entraining admixture in concrete
exposed to repeated freezing and thawing?
CERTIFICATION EXAMINATION COMPLETE QUESTIONS
AND DETAILED SOLUTIONS LATEST UPDATE THIS YEAR
JUST RELEASED
1.
A concrete mixture has adequate compressive strength but repeatedly
shows excessive slump loss during transportation. Which factor should
be investigated first?
A. Aggregate color
B. Cement fineness only
C. Water demand, admixture compatibility, and temperature effects
D. Formwork dimensions
Answer: C
Rationale: Slump loss can result from temperature, hydration rate,
aggregate absorption, and interactions between cementitious materials
and chemical admixtures.
2.
When determining concrete yield from batch weights and measured
unit weight, which calculation provides the most appropriate estimate?
A. Total batch mass divided by measured unit weight
B. Cement mass divided by water mass
,C. Aggregate mass divided by cement content
D. Water mass multiplied by slump
Answer: A
Rationale: Concrete yield is calculated by dividing the total mass of
freshly batched materials by the measured unit weight of concrete.
3.
Why is maintaining a consistent water-cementitious materials ratio
particularly important when producing strength-controlled concrete
mixtures?
A. It controls aggregate color
B. It strongly influences strength, durability, permeability, and
consistency
C. It eliminates air entrainment
D. It determines cement storage capacity
Answer: B
Rationale: The water-to-cementitious-materials ratio substantially
affects hydration products, porosity, strength development,
permeability, and durability.
4.
A technician obtains significantly different slump results from two
samples taken from the same truck. What should be evaluated?
,A. Testing procedure, sampling location, and concrete uniformity
B. Cement bag labeling
C. Aggregate mineral color
D. Truck tire pressure
Answer: A
Rationale: Sampling and testing inconsistencies, segregation, discharge
timing, and batch nonuniformity can produce substantially different
slump measurements.
5.
What is the primary purpose of determining the moisture condition of
aggregates before batching concrete?
A. To determine cement color
B. To accurately calculate aggregate and mixing-water contributions
C. To increase aggregate size
D. To eliminate air entrainment
Answer: B
Rationale: Aggregate moisture directly changes both aggregate batch
weights and effective mixing water, influencing slump and water-
cementitious ratio.
6.
If aggregate contains free surface moisture exceeding its absorption
capacity, what happens to the concrete mixture?
, A. Aggregate contributes additional water to the mixture
B. Aggregate removes all mixing water
C. Cement content automatically increases
D. Air content becomes zero
Answer: A
Rationale: Surface moisture beyond aggregate absorption contributes
water to the concrete and must be included when adjusting batch
water.
7.
Which aggregate condition represents saturated surface-dry material?
A. Completely dry pores and dry surface
B. Pores filled with water while the external surface remains dry
C. Completely submerged aggregate
D. Aggregate containing visible free surface water
Answer: B
Rationale: Saturated surface-dry aggregate has its internal pores filled
while no free water remains on the particle surface.
8.
What is the principal purpose of an air-entraining admixture in concrete
exposed to repeated freezing and thawing?
