ACI Concrete Field-Testing Technician
Grade 1 Exam Actual Exam 2026/2027
with Detailed Rationales | Complete
Exam-Style Questions | Pass Guaranteed
– A+ Graded
Q1: According to ASTM C172/C172M, what is the minimum sample size for fresh
concrete?
A. 0.5 ft³ (14 L)
B. 0.75 ft³ (21 L)
C. 1 ft³ (28 L) [CORRECT]
D. 1.5 ft³ (42 L)
Correct Answer: C
Rationale: Correct because ASTM C172/C172M explicitly states the minimum sample size
is 1 ft³ (28 L) for fresh concrete testing. This ensures the sample is representative of the
entire batch.
Q2: What is the diameter of the tamping rod used for slump testing per ASTM
C143/C143M?
A. 1/2 inch (12.7 mm)
,B. 5/8 inch (16 mm) [CORRECT]
C. 3/4 inch (19 mm)
D. 1 inch (25 mm)
Correct Answer: B
Rationale: Correct because ASTM C143/C143M specifies a tamping rod with a 5/8 inch
(16 mm) diameter and a hemispherical tip. This matches the standard equipment
requirements for slump testing.
Q3: How is the theoretical density of concrete calculated per ASTM C138/C138M?
A. Mass of concrete divided by volume of measure
B. Combined mass of all ingredients divided by absolute volume of all ingredients
C. Combined mass of all ingredients divided by absolute volume of all ingredients
[CORRECT]
D. Actual density minus air content
Correct Answer: C
Rationale: Correct because ASTM C138/C138M defines theoretical density as the
combined mass of all ingredients divided by the absolute volume of all ingredients. This is
used to calculate air content gravimetrically.
Q4: What is the initial air pressure typically applied during the air content test using the
pressure method (ASTM C231/C231M)?
A. 10 psi (69 kPa)
B. 12 psi (83 kPa)
C. 14.5 psi (100 kPa) [CORRECT]
D. 20 psi (138 kPa)
Correct Answer: C
Rationale: Correct because ASTM C231/C231M requires an initial air pressure of 14.5 psi
,(100 kPa) for the pressure method, which aligns with Boyle's Law for measuring air
volume. This is the standard starting pressure for the test.
Q5: When testing air content using the volumetric method (ASTM C173/C173M), how
much 70% isopropyl alcohol is added to the concrete sample?
A. 0.5 mL
B. 1 mL [CORRECT]
C. 2 mL
D. 5 mL
Correct Answer: B
Rationale: Correct because ASTM C173/C173M specifies adding 1 mL of 70% isopropyl
alcohol to break foam and release entrained air during the volumetric test. This is a critical
step to ensure accurate air content measurement.
Q6: What is the required accuracy of a thermometer used for measuring concrete
temperature per ASTM C1064/C1064M?
A. ±1°F (0.5°C)
B. ±0.5°F (0.5°C) of standard [CORRECT]
C. ±2°F (1°C)
D. ±0.25°F (0.1°C)
Correct Answer: B
Rationale: Correct because ASTM C1064/C1064M mandates that the thermometer must
have an accuracy of ±0.5°F (0.5°C) of the standard to ensure precise temperature
measurements of fresh concrete.
Q7: What is the loading rate for a 6x12 inch concrete cylinder during compressive strength
testing per ASTM C39/C39M?
A. 35 ± 7 psi/s (0.25 ± 0.05 MPa/s)
, B. 30 ± 5 psi/s [CORRECT]
C. 25 ± 5 psi/s
D. 40 ± 7 psi/s
Correct Answer: B
Rationale: Correct because ASTM C39/C39M specifies a loading rate of 30 ± 5 psi/s for
6x12 inch cylinders, which is different from the 35 ± 7 psi/s rate for 4x8 inch cylinders. This
ensures consistent failure rates during testing.
Q8: How many layers are required when rodding a 6x12 inch concrete cylinder mold per
ASTM C31/C31M?
A. 2 layers
B. 3 layers [CORRECT]
C. 4 layers
D. 5 layers
Correct Answer: B
Rationale: Correct because ASTM C31/C31M specifies that 6x12 inch cylinder molds
must be filled in 3 equal layers, each rodded 25 times, to ensure proper consolidation of
the concrete specimen.
Q9: What is the minimum immersion depth required for a bi-metallic thermometer when
measuring concrete temperature per ASTM C1064/C1064M?
A. 1 inch (25 mm)
B. 2 inches (50 mm)
C. 3 inches (75 mm) [CORRECT]
D. 4 inches (100 mm)
Correct Answer: C
Rationale: Correct because ASTM C1064/C1064M requires a minimum immersion depth
Grade 1 Exam Actual Exam 2026/2027
with Detailed Rationales | Complete
Exam-Style Questions | Pass Guaranteed
– A+ Graded
Q1: According to ASTM C172/C172M, what is the minimum sample size for fresh
concrete?
A. 0.5 ft³ (14 L)
B. 0.75 ft³ (21 L)
C. 1 ft³ (28 L) [CORRECT]
D. 1.5 ft³ (42 L)
Correct Answer: C
Rationale: Correct because ASTM C172/C172M explicitly states the minimum sample size
is 1 ft³ (28 L) for fresh concrete testing. This ensures the sample is representative of the
entire batch.
Q2: What is the diameter of the tamping rod used for slump testing per ASTM
C143/C143M?
A. 1/2 inch (12.7 mm)
,B. 5/8 inch (16 mm) [CORRECT]
C. 3/4 inch (19 mm)
D. 1 inch (25 mm)
Correct Answer: B
Rationale: Correct because ASTM C143/C143M specifies a tamping rod with a 5/8 inch
(16 mm) diameter and a hemispherical tip. This matches the standard equipment
requirements for slump testing.
Q3: How is the theoretical density of concrete calculated per ASTM C138/C138M?
A. Mass of concrete divided by volume of measure
B. Combined mass of all ingredients divided by absolute volume of all ingredients
C. Combined mass of all ingredients divided by absolute volume of all ingredients
[CORRECT]
D. Actual density minus air content
Correct Answer: C
Rationale: Correct because ASTM C138/C138M defines theoretical density as the
combined mass of all ingredients divided by the absolute volume of all ingredients. This is
used to calculate air content gravimetrically.
Q4: What is the initial air pressure typically applied during the air content test using the
pressure method (ASTM C231/C231M)?
A. 10 psi (69 kPa)
B. 12 psi (83 kPa)
C. 14.5 psi (100 kPa) [CORRECT]
D. 20 psi (138 kPa)
Correct Answer: C
Rationale: Correct because ASTM C231/C231M requires an initial air pressure of 14.5 psi
,(100 kPa) for the pressure method, which aligns with Boyle's Law for measuring air
volume. This is the standard starting pressure for the test.
Q5: When testing air content using the volumetric method (ASTM C173/C173M), how
much 70% isopropyl alcohol is added to the concrete sample?
A. 0.5 mL
B. 1 mL [CORRECT]
C. 2 mL
D. 5 mL
Correct Answer: B
Rationale: Correct because ASTM C173/C173M specifies adding 1 mL of 70% isopropyl
alcohol to break foam and release entrained air during the volumetric test. This is a critical
step to ensure accurate air content measurement.
Q6: What is the required accuracy of a thermometer used for measuring concrete
temperature per ASTM C1064/C1064M?
A. ±1°F (0.5°C)
B. ±0.5°F (0.5°C) of standard [CORRECT]
C. ±2°F (1°C)
D. ±0.25°F (0.1°C)
Correct Answer: B
Rationale: Correct because ASTM C1064/C1064M mandates that the thermometer must
have an accuracy of ±0.5°F (0.5°C) of the standard to ensure precise temperature
measurements of fresh concrete.
Q7: What is the loading rate for a 6x12 inch concrete cylinder during compressive strength
testing per ASTM C39/C39M?
A. 35 ± 7 psi/s (0.25 ± 0.05 MPa/s)
, B. 30 ± 5 psi/s [CORRECT]
C. 25 ± 5 psi/s
D. 40 ± 7 psi/s
Correct Answer: B
Rationale: Correct because ASTM C39/C39M specifies a loading rate of 30 ± 5 psi/s for
6x12 inch cylinders, which is different from the 35 ± 7 psi/s rate for 4x8 inch cylinders. This
ensures consistent failure rates during testing.
Q8: How many layers are required when rodding a 6x12 inch concrete cylinder mold per
ASTM C31/C31M?
A. 2 layers
B. 3 layers [CORRECT]
C. 4 layers
D. 5 layers
Correct Answer: B
Rationale: Correct because ASTM C31/C31M specifies that 6x12 inch cylinder molds
must be filled in 3 equal layers, each rodded 25 times, to ensure proper consolidation of
the concrete specimen.
Q9: What is the minimum immersion depth required for a bi-metallic thermometer when
measuring concrete temperature per ASTM C1064/C1064M?
A. 1 inch (25 mm)
B. 2 inches (50 mm)
C. 3 inches (75 mm) [CORRECT]
D. 4 inches (100 mm)
Correct Answer: C
Rationale: Correct because ASTM C1064/C1064M requires a minimum immersion depth
