Technician Grade I
Practice Examination
Course: ACI Concrete Field-Testing
Technician Grade I
Total Questions: 150
Question 1 – Slump Test
A field technician is performing a slump test on a concrete sample. After
rodding the final layer and striking off the concrete, the technician
observes a slight deficiency in the amount of concrete in the measure.
What is the correct course of action?
A) Discard the sample and obtain a new one.
B) Ignore the deficiency as it is within acceptable tolerance.
C) Add a representative portion of the concrete from the sample before
strike-off.
D) Add a small amount of water to the mix to bring it to the proper level.
,Correct Answer: C
Rationale:
When there is a slight deficiency in the measure after consolidation, the
standard procedure is to add a representative portion of the concrete to
ensure a proper strike-off, which is critical for accurate measurement.
Question 2 – Air Content (Volumetric Method)
The volumetric method for determining the air content of concrete is
applicable to mixtures containing which of the following aggregate types?
A) Only lightweight aggregates.
B) Only normal-weight aggregates.
C) All types of aggregates, including lightweight, normal-weight, and
heavy-weight.
D) Only aggregates with a maximum size of 1 inch (25 mm).
Correct Answer: C
Rationale:
The volumetric method is versatile and can be used on concrete
containing any type of aggregate, whether it is lightweight, normal-
weight, or heavy-weight, as it does not rely on aggregate specific gravity
for calculations.
Question 3 – Consolidation by Rodding
,When consolidating a concrete sample by rodding in a standard slump
cone, what is the specified depth of penetration for the rod in the second
and final layers?
A) Approximately 1 inch (25 mm) into the previous layer.
B) To the full depth of the concrete in the mold.
C) To the bottom of the layer being rodded.
D) Approximately 2 inches (50 mm) into the previous layer.
Correct Answer: A
Rationale:
To ensure proper bonding and consolidation between layers, the rod must
penetrate approximately 1 inch (25 mm) into the previously rodded layer
for the second and final layers, while the first layer is rodded to its full
depth.
Question 4 – Strike-Off Tools
Following the consolidation of the final layer of concrete in a measure,
which of the following tools is permitted to be used to strike off the top
surface?
A) A wooden float.
B) A magnesium trowel.
C) A strike-off bar or a metal, glass, or acrylic plate.
D) The tamping rod.
Correct Answer: C
, Rationale:
The standard permits the use of a flat, straight strike-off bar, or a flat
metal, glass, or acrylic plate to strike off the concrete, ensuring a smooth
and even surface for accurate measurement.
[Page 2]
Question 5 – Air Content (Volumetric Method)
During the volumetric method of determining air content, what is the
approximate volume of the measuring cup used to add water to the air
meter, expressed as a percentage of the bowl’s volume?
A) 0.50% ± 0.02%
B) 1.00% ± 0.04%
C) 1.50% ± 0.05%
D) 2.00% ± 0.10%
Correct Answer: B
Rationale:
The standard specifies that the measuring cup used for adding water to
the air meter should have a volume of approximately 1.00% ± 0.04% of
the volume of the air meter bowl to ensure the correct amount of water is
introduced.
Question 6 – Tamping Rod Specifications