ACI Concrete Strength Testing Technician Exam
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Question 1
What is the standard size of a concrete cylinder used for compressive
strength testing in most field applications?
A. 3 in × 6 in
B. 4 in × 8 in
C. 6 in × 12 in
D. 8 in × 16 in
Answer: C
Rationale: The most commonly used standard cylinder size for
compressive strength testing under ASTM C39 is 6 in × 12 in, which
provides reliable and consistent strength results for structural
concrete.
,Question 2
According to ASTM standards, concrete test cylinders should initially be
stored in a curing environment at what temperature range?
A. 10–15°C
B. 18–24°C
C. 23 ± 2°C
D. 30–35°C
Answer: C
Rationale: Initial curing of concrete cylinders requires a controlled
environment of 23 ± 2°C to ensure proper hydration and consistent
strength development.
Question 3
What is the purpose of capping concrete cylinders before compression
testing?
A. To increase cylinder height
B. To prevent moisture loss
C. To provide smooth, parallel loading surfaces
D. To reduce testing time
,Answer: C
Rationale: Capping ensures that the ends of the cylinder are smooth
and parallel so that load is evenly distributed during compressive
strength testing.
Question 4
Which ASTM standard governs the compressive strength testing of
cylindrical concrete specimens?
A. ASTM C31
B. ASTM C39
C. ASTM C143
D. ASTM C1064
Answer: B
Rationale: ASTM C39 outlines the procedure for determining
compressive strength of cylindrical concrete specimens.
Question 5
What is the typical loading rate applied during a concrete compressive
strength test?
A. 10–15 psi/sec
, B. 25–30 psi/sec
C. 35 ± 7 psi/sec
D. 50–60 psi/sec
Answer: C
Rationale: ASTM C39 specifies a loading rate of 35 ± 7 psi per second
to ensure consistent failure conditions.
Question 6
How long should concrete cylinders remain in initial field curing
conditions before being transported to a laboratory?
A. 12 ± 2 hours
B. 24 ± 8 hours
C. 48 ± 12 hours
D. 72 ± 24 hours
Answer: B
Rationale: Cylinders are typically kept in field curing conditions for 24
± 8 hours before transport to a controlled curing facility.
Question 7
Questions With Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A | Instant
Download Pdf
Question 1
What is the standard size of a concrete cylinder used for compressive
strength testing in most field applications?
A. 3 in × 6 in
B. 4 in × 8 in
C. 6 in × 12 in
D. 8 in × 16 in
Answer: C
Rationale: The most commonly used standard cylinder size for
compressive strength testing under ASTM C39 is 6 in × 12 in, which
provides reliable and consistent strength results for structural
concrete.
,Question 2
According to ASTM standards, concrete test cylinders should initially be
stored in a curing environment at what temperature range?
A. 10–15°C
B. 18–24°C
C. 23 ± 2°C
D. 30–35°C
Answer: C
Rationale: Initial curing of concrete cylinders requires a controlled
environment of 23 ± 2°C to ensure proper hydration and consistent
strength development.
Question 3
What is the purpose of capping concrete cylinders before compression
testing?
A. To increase cylinder height
B. To prevent moisture loss
C. To provide smooth, parallel loading surfaces
D. To reduce testing time
,Answer: C
Rationale: Capping ensures that the ends of the cylinder are smooth
and parallel so that load is evenly distributed during compressive
strength testing.
Question 4
Which ASTM standard governs the compressive strength testing of
cylindrical concrete specimens?
A. ASTM C31
B. ASTM C39
C. ASTM C143
D. ASTM C1064
Answer: B
Rationale: ASTM C39 outlines the procedure for determining
compressive strength of cylindrical concrete specimens.
Question 5
What is the typical loading rate applied during a concrete compressive
strength test?
A. 10–15 psi/sec
, B. 25–30 psi/sec
C. 35 ± 7 psi/sec
D. 50–60 psi/sec
Answer: C
Rationale: ASTM C39 specifies a loading rate of 35 ± 7 psi per second
to ensure consistent failure conditions.
Question 6
How long should concrete cylinders remain in initial field curing
conditions before being transported to a laboratory?
A. 12 ± 2 hours
B. 24 ± 8 hours
C. 48 ± 12 hours
D. 72 ± 24 hours
Answer: B
Rationale: Cylinders are typically kept in field curing conditions for 24
± 8 hours before transport to a controlled curing facility.
Question 7
