1
ACI EN STANDARDS CONCRETE COMPRESSIVE STRENGTH
TESTING TECHNICIAN EXAM FULL PACKAGE QUESTIONS ANSWERS
AND RATIONALES 2026-27 LATEST UPDATED VERSION INSTANT
DOWNLOAD PDF..!!
INTRODUCTION
The ACI EN Standards Concrete Compressive Strength Testing Technician Exam is a specialised certification
assessment administered jointly by the American Concrete Institute (ACI) and the Institute of Concrete
Technology (ICT), designed to validate a technician's competence in performing compressive strength tests on
hardened concrete in accordance with European Norm (EN) standards. This certification is a critical milestone
for laboratory technicians, quality control personnel, and testing operatives who must demonstrate that
concrete meets specified strength requirements using the EN 12390 series of standards rather than the more
familiar ASTM methods. The examination requires candidates to possess a working knowledge of specimen
preparation, curing regimes, testing machine requirements, loading procedures, and the interpretation of
results, all within the framework of EN 12390-1 (shape, dimensions and moulds), EN 12390-2 (making and
curing specimens), EN 12390-3 (compressive strength of test specimens), and EN 12504-1 (cored specimens).
The written examination consists of approximately 30 to 36 multiple-choice questions, but true competency
demands a far deeper understanding than a minimal question count might suggest. This question bank has
been expanded to 200 items to provide exhaustive coverage of the technical content, procedural nuances, and
practical judgment required to pass on the first attempt and to perform testing that is both accurate and
defensible.
CORE DOMAINS TESTED
1. EN 12390-1: Specimen Geometry and Moulds – Cube and cylinder dimensions, tolerances, mould
construction, and the relationship between specimen size and aggregate size.
2. EN 12390-2: Making and Curing Specimens – Sampling, mould preparation, compaction methods,
demoulding, initial curing, standard curing conditions, and transport.
3. EN 12390-3: Compressive Strength Testing – Machine verification, bearing plate requirements,
specimen centring, loading rate, failure modes, and calculation of compressive strength.
4. EN 12504-1: Cored Specimens – Core extraction, examination, preparation (cutting, grinding,
capping), length-to-diameter ratios, and strength correction.
5. Test Machine Requirements and Calibration – Force indication, accuracy, verification intervals, and
the classification of testing machines.
6. Specimen Preparation and Surface Condition – Capping materials, grinding, sulphur mortars, and the
effect of surface irregularity on results.
7. Curing Regimes and Age at Test – Standard 28-day curing, accelerated curing, early-age testing, and
the effect of temperature and moisture.
8. Quality Control, Records, and Reporting – Test report content, traceability, calculation checks, and the
evaluation of results against conformity criteria.
9. Safety and Laboratory Practice – Handling heavy specimens, machine guarding, dust control, and safe
disposal of fractured concrete.
,2
Q1: According to EN 12390-1, which nominal cube size is the
reference specimen for compressive strength testing, although other
sizes are permitted?
A) 100 mm
B) 150 mm
C) 200 mm
D) 300 mm
Rationale: The correct answer is B. EN 12390-1 establishes the 150
mm cube as the reference specimen, and the compressive strength of
other cube sizes is converted to the equivalent 150 mm cube strength
using established factors. Option A is a permitted smaller size used
when aggregate grading is suitable, but it is not the reference. Option
C is a permitted larger size, not the reference. Option D is not a
standard cube dimension for routine compressive strength testing
under EN 12390-1.
Q2: A technician is preparing to cast 100 mm cubes. According to EN
12390-1, which maximum aggregate size is generally considered
acceptable for this mould size?
A) 40 mm
B) 31.5 mm
C) 22.4 mm
D) 10 mm
Rationale: The correct answer is C. EN 12390-1 requires the specimen
dimension to be at least three times the maximum aggregate size, so
a 100 mm cube is appropriate for concrete with a maximum
aggregate size of approximately 22.4 mm or smaller. Option A is too
large and would violate the three-times rule. Option B is also too
large for a 100 mm cube. Option D is unnecessarily restrictive and
,3
would exclude many normal concretes, but the question asks what is
acceptable, and 22.4 mm is the practical upper limit.
Q3: When casting cylindrical specimens under EN 12390-2, which
mould dimension is most commonly used for compressive strength
testing?
A) 100 mm diameter × 200 mm height
B) 150 mm diameter × 300 mm height
C) 150 mm diameter × 150 mm height
D) 200 mm diameter × 400 mm height
Rationale: The correct answer is B. The standard cylinder for
compressive strength testing under EN 12390-2 is 150 mm diameter
by 300 mm height, giving the required length-to-diameter ratio of 2.
Option A is a smaller cylinder used for some applications but is not
the standard reference size. Option C is a cube-like proportion and is
not the standard cylinder geometry. Option D is an oversized cylinder
that is rarely used for routine testing.
Q4: Under EN 12390-2, what is the required curing temperature for
standard moist curing of test specimens?
A) 15 ± 2°C
B) 20 ± 2°C
C) 23 ± 2°C
D) 25 ± 2°C
Rationale: The correct answer is B. EN 12390-2 specifies a standard
curing temperature of 20 ± 2°C for specimens cured in water or a
moist environment. Option A is the curing temperature used in some
other standards but is not the EN requirement. Option C is the ASTM
C511 curing temperature, not the EN standard. Option D is outside
the tolerance permitted by EN 12390-2.
, 4
Q5: A technician is verifying the compression testing machine before
use. According to EN 12390-3, what is the maximum permissible
error of the force indication over the relevant range?
A) ± 0.5%
B) ± 1.0%
C) ± 2.0%
D) ± 3.0%
Rationale: The correct answer is B. EN 12390-3 requires the force-
indicating system to have a maximum permissible error of ± 1.0% of
the indicated force, or ± 1.0% of the true force, depending on the
verification method. Option A is more stringent than the standard
requires and would be difficult to achieve with many machines.
Option C is too loose and would not satisfy the accuracy requirements
of EN 12390-3. Option D is substantially outside the acceptable
tolerance and would invalidate test results.
Q6: During a compressive strength test, the loading rate must be
controlled. Which rate is specified by EN 12390-3 for standard cube
specimens?
A) 0.1 ± 0.05 MPa/s
B) 0.5 ± 0.2 MPa/s
C) 1.0 ± 0.5 MPa/s
D) 2.0 ± 1.0 MPa/s
Rationale: The correct answer is B. EN 12390-3 specifies a loading
rate of 0.5 ± 0.2 MPa/s for cube specimens, ensuring that failure
occurs within a reasonable time without introducing dynamic effects.
Option A is too slow and may allow creep or environmental effects to
influence the result. Option C is too fast and may produce a higher
apparent strength. Option D is far too rapid and would not comply
with the standard.
ACI EN STANDARDS CONCRETE COMPRESSIVE STRENGTH
TESTING TECHNICIAN EXAM FULL PACKAGE QUESTIONS ANSWERS
AND RATIONALES 2026-27 LATEST UPDATED VERSION INSTANT
DOWNLOAD PDF..!!
INTRODUCTION
The ACI EN Standards Concrete Compressive Strength Testing Technician Exam is a specialised certification
assessment administered jointly by the American Concrete Institute (ACI) and the Institute of Concrete
Technology (ICT), designed to validate a technician's competence in performing compressive strength tests on
hardened concrete in accordance with European Norm (EN) standards. This certification is a critical milestone
for laboratory technicians, quality control personnel, and testing operatives who must demonstrate that
concrete meets specified strength requirements using the EN 12390 series of standards rather than the more
familiar ASTM methods. The examination requires candidates to possess a working knowledge of specimen
preparation, curing regimes, testing machine requirements, loading procedures, and the interpretation of
results, all within the framework of EN 12390-1 (shape, dimensions and moulds), EN 12390-2 (making and
curing specimens), EN 12390-3 (compressive strength of test specimens), and EN 12504-1 (cored specimens).
The written examination consists of approximately 30 to 36 multiple-choice questions, but true competency
demands a far deeper understanding than a minimal question count might suggest. This question bank has
been expanded to 200 items to provide exhaustive coverage of the technical content, procedural nuances, and
practical judgment required to pass on the first attempt and to perform testing that is both accurate and
defensible.
CORE DOMAINS TESTED
1. EN 12390-1: Specimen Geometry and Moulds – Cube and cylinder dimensions, tolerances, mould
construction, and the relationship between specimen size and aggregate size.
2. EN 12390-2: Making and Curing Specimens – Sampling, mould preparation, compaction methods,
demoulding, initial curing, standard curing conditions, and transport.
3. EN 12390-3: Compressive Strength Testing – Machine verification, bearing plate requirements,
specimen centring, loading rate, failure modes, and calculation of compressive strength.
4. EN 12504-1: Cored Specimens – Core extraction, examination, preparation (cutting, grinding,
capping), length-to-diameter ratios, and strength correction.
5. Test Machine Requirements and Calibration – Force indication, accuracy, verification intervals, and
the classification of testing machines.
6. Specimen Preparation and Surface Condition – Capping materials, grinding, sulphur mortars, and the
effect of surface irregularity on results.
7. Curing Regimes and Age at Test – Standard 28-day curing, accelerated curing, early-age testing, and
the effect of temperature and moisture.
8. Quality Control, Records, and Reporting – Test report content, traceability, calculation checks, and the
evaluation of results against conformity criteria.
9. Safety and Laboratory Practice – Handling heavy specimens, machine guarding, dust control, and safe
disposal of fractured concrete.
,2
Q1: According to EN 12390-1, which nominal cube size is the
reference specimen for compressive strength testing, although other
sizes are permitted?
A) 100 mm
B) 150 mm
C) 200 mm
D) 300 mm
Rationale: The correct answer is B. EN 12390-1 establishes the 150
mm cube as the reference specimen, and the compressive strength of
other cube sizes is converted to the equivalent 150 mm cube strength
using established factors. Option A is a permitted smaller size used
when aggregate grading is suitable, but it is not the reference. Option
C is a permitted larger size, not the reference. Option D is not a
standard cube dimension for routine compressive strength testing
under EN 12390-1.
Q2: A technician is preparing to cast 100 mm cubes. According to EN
12390-1, which maximum aggregate size is generally considered
acceptable for this mould size?
A) 40 mm
B) 31.5 mm
C) 22.4 mm
D) 10 mm
Rationale: The correct answer is C. EN 12390-1 requires the specimen
dimension to be at least three times the maximum aggregate size, so
a 100 mm cube is appropriate for concrete with a maximum
aggregate size of approximately 22.4 mm or smaller. Option A is too
large and would violate the three-times rule. Option B is also too
large for a 100 mm cube. Option D is unnecessarily restrictive and
,3
would exclude many normal concretes, but the question asks what is
acceptable, and 22.4 mm is the practical upper limit.
Q3: When casting cylindrical specimens under EN 12390-2, which
mould dimension is most commonly used for compressive strength
testing?
A) 100 mm diameter × 200 mm height
B) 150 mm diameter × 300 mm height
C) 150 mm diameter × 150 mm height
D) 200 mm diameter × 400 mm height
Rationale: The correct answer is B. The standard cylinder for
compressive strength testing under EN 12390-2 is 150 mm diameter
by 300 mm height, giving the required length-to-diameter ratio of 2.
Option A is a smaller cylinder used for some applications but is not
the standard reference size. Option C is a cube-like proportion and is
not the standard cylinder geometry. Option D is an oversized cylinder
that is rarely used for routine testing.
Q4: Under EN 12390-2, what is the required curing temperature for
standard moist curing of test specimens?
A) 15 ± 2°C
B) 20 ± 2°C
C) 23 ± 2°C
D) 25 ± 2°C
Rationale: The correct answer is B. EN 12390-2 specifies a standard
curing temperature of 20 ± 2°C for specimens cured in water or a
moist environment. Option A is the curing temperature used in some
other standards but is not the EN requirement. Option C is the ASTM
C511 curing temperature, not the EN standard. Option D is outside
the tolerance permitted by EN 12390-2.
, 4
Q5: A technician is verifying the compression testing machine before
use. According to EN 12390-3, what is the maximum permissible
error of the force indication over the relevant range?
A) ± 0.5%
B) ± 1.0%
C) ± 2.0%
D) ± 3.0%
Rationale: The correct answer is B. EN 12390-3 requires the force-
indicating system to have a maximum permissible error of ± 1.0% of
the indicated force, or ± 1.0% of the true force, depending on the
verification method. Option A is more stringent than the standard
requires and would be difficult to achieve with many machines.
Option C is too loose and would not satisfy the accuracy requirements
of EN 12390-3. Option D is substantially outside the acceptable
tolerance and would invalidate test results.
Q6: During a compressive strength test, the loading rate must be
controlled. Which rate is specified by EN 12390-3 for standard cube
specimens?
A) 0.1 ± 0.05 MPa/s
B) 0.5 ± 0.2 MPa/s
C) 1.0 ± 0.5 MPa/s
D) 2.0 ± 1.0 MPa/s
Rationale: The correct answer is B. EN 12390-3 specifies a loading
rate of 0.5 ± 0.2 MPa/s for cube specimens, ensuring that failure
occurs within a reasonable time without introducing dynamic effects.
Option A is too slow and may allow creep or environmental effects to
influence the result. Option C is too fast and may produce a higher
apparent strength. Option D is far too rapid and would not comply
with the standard.
