Illinois Materials Testing Technician

Illinois Materials Testing Technician Certification Examination Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary purpose of a slump test in concrete testing?
• Determine compressive strength
• Measure air content
• Assess workability
• Evaluate water-cement ratio

Rationale: The slump test measures the consistency or workability of

fresh concrete, indicating how easily it can be placed and compacted.

• Which type of aggregate is most suitable for concrete pavements

requiring high durability?

• Lightweight aggregate 1 / 4

• Crushed stone
• Pea gravel
• Expanded shale

Rationale: Crushed stone provides better interlock and strength,

making it suitable for durable concrete pavements.

• What is the standard curing period for concrete to achieve 70% of its

design strength?

• 3 days
• 7 days
• 28 days
• 56 days

Rationale: Concrete generally reaches about 70% of its design

strength at 28 days under standard curing conditions.

• Which device is commonly used to test the compressive strength of

concrete cylinders in the field?

• Slump cone
• Air meter
• Compression testing machine
• Vicat needle

Rationale: A compression testing machine applies controlled load to

concrete cylinders to measure compressive strength.

5. The purpose of a sieve analysis in soil testing is to determine:

• Moisture content 2 / 4

• Compaction
• Particle size distribution
• Shear strength

Rationale: Sieve analysis separates soil into size fractions, allowing

determination of particle size distribution.

• Which method is used to determine in-place density of soils?
• Proctor test
• Nuclear density gauge
• Grain size analysis
• Atterberg limits

Rationale: Nuclear density gauges measure the density of soil in the

field, providing quick in-place compaction results.

• The Atterberg limits are used to classify which type of material?
• Sand
• Clay
• Gravel
• Crushed stone

Rationale: Atterberg limits (liquid and plastic limits) describe the

consistency and plasticity of fine-grained soils like clay.

• What is the minimum curing temperature for freshly placed concrete

to ensure proper hydration?

• 25°F (-4°C)
• 40°F (4°C) 3 / 4

• 50°F (10°C)
• 70°F (21°C)

Rationale: Concrete should be maintained above 50°F (10°C) during

curing to allow adequate hydration and strength development.

• Which test is used to determine the air content of freshly mixed

concrete?

• Slump test
• Compressive test
• Pressure method or volumetric method
• Flexural test

Rationale: Air content in fresh concrete is measured using pressure or

volumetric methods, ensuring durability and freeze-thaw resistance.

10. The Proctor compaction test determines:

• Soil permeability
• Particle size distribution
• Maximum dry density and optimum moisture content
• Shear strength

Rationale: The Proctor test identifies the moisture content at which

soil achieves maximum dry density.

• What is the purpose of a penetration test in asphalt testing?
• Measure compaction
• Determine viscosity
• Determine hardness or consistency
• / 4