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NICET Soils Level 1 Ultimate Guide to Soil and Aggregate
Testing EXAM Questions and Correct Answers with
EXPLANATIONS LATEST THIS YEAR
Exam Coverage Summary: ASTM C117 (Washing #200), C136 (Sieve Analysis), D75 (Sampling), D698
(Standard Proctor), D1557 (Modified Proctor), D1140 (Soil Washing), D1556 (Sand Cone), D2166
(Unconfined Strength), D2216 (Moisture Content), D2488 (Visual Classification), D4318 (Atterberg
Limits), D6938 (Nuclear Gauge), and D3665 (Random Sampling).
1. A technician performs a sieve analysis on a coarse aggregate sample. According to ASTM C136, what
defines the endpoint of the sieving operation?
A) 5 minutes of continuous machine shaking
B) When the material turns dark in color
C) Not more than 1% of the material retained on any sieve passes during 1 minute of hand sieving
D) When the material stops moving on the sieve
Rationale: The endpoint is determined by adequacy of sieving, verified when hand sieving moves less
than 1% of the retained mass through the sieve.
2. During ASTM D2216, a soil sample is placed in a drying oven. What is the standard temperature range
required for moisture content determination?
A) 60 ± 5°C
B) 110 ± 5°C
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C) 200 ± 5°C
D) 350 ± 5°C
Rationale: The standard oven drying temperature is 110±5°C, hot enough to drive off free water without
burning organic matter or breaking down clay minerals.
3. A contractor is compacting fill for a highway embankment. Which laboratory test data is required to
calculate the percent compaction in the field?
A) Atterberg Limits (D4318)
B) Maximum Dry Density (D698 or D1557)
C) Unconfined Compressive Strength (D2166)
D) Specific Gravity (D854)
Rationale: Percent compaction is the ratio of field dry density to laboratory maximum dry density
(Proctor) multiplied by 100.
4. A technician observes material accumulating on the No. 200 sieve during a wash test (C117). What
does this retained material represent?
A) Hydrated cement paste
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B) Particles larger than 75 µm
C) Silt and clay particles passing the sieve
D) Organic impurities
*Rationale: The No. 200 sieve has 75-micron openings; material retained on it is sand-sized or larger,
representing the coarse fraction.*
5. Following ASTM D3665 for random sampling, how should a technician select locations from a
stockpile to avoid bias?
A) Sample only the top surface for convenience
B) Sample the top, middle, and base on a random grid pattern regardless of appearance
C) Take one large sample from the center
D) Sample only the edges where material fell first
Rationale: Random sampling requires unbiased selection of increments from the entire mass to produce
a representative sample.
6. While performing a Standard Proctor (D698) on a clay soil, the technician notices the soil is "pumping"
or pushing up under the rammer. What is the most likely cause?
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A) The mold is too large
B) The moisture content is too high (wet of optimum)
C) The soil has too much gravel
D) The rammer weight is calibrated wrong
Rationale: When moisture exceeds optimum, water fills the voids and prevents compaction energy from
densifying the soil, causing the mass to extrude.
7. When performing visual classification (D2488), the technician defines a soil as "lean clay" based on
the feel test. What are the defining characteristics of clay?
A) Gritty texture and visible individual particles
B) High dry strength and slow reaction to water (dilatancy)
C) No plasticity and decomposed vegetation
D) Uniform particle size and high permeability
Rationale: Fine-grained soils (clays) exhibit plasticity, high dry strength, and slow water shaking reactions
compared to silts.
NICET Soils Level 1 Ultimate Guide to Soil and Aggregate
Testing EXAM Questions and Correct Answers with
EXPLANATIONS LATEST THIS YEAR
Exam Coverage Summary: ASTM C117 (Washing #200), C136 (Sieve Analysis), D75 (Sampling), D698
(Standard Proctor), D1557 (Modified Proctor), D1140 (Soil Washing), D1556 (Sand Cone), D2166
(Unconfined Strength), D2216 (Moisture Content), D2488 (Visual Classification), D4318 (Atterberg
Limits), D6938 (Nuclear Gauge), and D3665 (Random Sampling).
1. A technician performs a sieve analysis on a coarse aggregate sample. According to ASTM C136, what
defines the endpoint of the sieving operation?
A) 5 minutes of continuous machine shaking
B) When the material turns dark in color
C) Not more than 1% of the material retained on any sieve passes during 1 minute of hand sieving
D) When the material stops moving on the sieve
Rationale: The endpoint is determined by adequacy of sieving, verified when hand sieving moves less
than 1% of the retained mass through the sieve.
2. During ASTM D2216, a soil sample is placed in a drying oven. What is the standard temperature range
required for moisture content determination?
A) 60 ± 5°C
B) 110 ± 5°C
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C) 200 ± 5°C
D) 350 ± 5°C
Rationale: The standard oven drying temperature is 110±5°C, hot enough to drive off free water without
burning organic matter or breaking down clay minerals.
3. A contractor is compacting fill for a highway embankment. Which laboratory test data is required to
calculate the percent compaction in the field?
A) Atterberg Limits (D4318)
B) Maximum Dry Density (D698 or D1557)
C) Unconfined Compressive Strength (D2166)
D) Specific Gravity (D854)
Rationale: Percent compaction is the ratio of field dry density to laboratory maximum dry density
(Proctor) multiplied by 100.
4. A technician observes material accumulating on the No. 200 sieve during a wash test (C117). What
does this retained material represent?
A) Hydrated cement paste
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B) Particles larger than 75 µm
C) Silt and clay particles passing the sieve
D) Organic impurities
*Rationale: The No. 200 sieve has 75-micron openings; material retained on it is sand-sized or larger,
representing the coarse fraction.*
5. Following ASTM D3665 for random sampling, how should a technician select locations from a
stockpile to avoid bias?
A) Sample only the top surface for convenience
B) Sample the top, middle, and base on a random grid pattern regardless of appearance
C) Take one large sample from the center
D) Sample only the edges where material fell first
Rationale: Random sampling requires unbiased selection of increments from the entire mass to produce
a representative sample.
6. While performing a Standard Proctor (D698) on a clay soil, the technician notices the soil is "pumping"
or pushing up under the rammer. What is the most likely cause?
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A) The mold is too large
B) The moisture content is too high (wet of optimum)
C) The soil has too much gravel
D) The rammer weight is calibrated wrong
Rationale: When moisture exceeds optimum, water fills the voids and prevents compaction energy from
densifying the soil, causing the mass to extrude.
7. When performing visual classification (D2488), the technician defines a soil as "lean clay" based on
the feel test. What are the defining characteristics of clay?
A) Gritty texture and visible individual particles
B) High dry strength and slow reaction to water (dilatancy)
C) No plasticity and decomposed vegetation
D) Uniform particle size and high permeability
Rationale: Fine-grained soils (clays) exhibit plasticity, high dry strength, and slow water shaking reactions
compared to silts.
