CPII Material Testing 2 — Questions and Answers
Question 1: What does the Los Angeles Abrasion test measure for aggregates?
- Moisture absorption capacity
- Resistance to degradation by abrasion and impact (Correct answer)
- Specific gravity and density
- Gradation and particle size distribution
Correct answer: Resistance to degradation by abrasion and impact
The LA Abrasion test measures the resistance of coarse aggregate to degradation by abrasion and impact using a rotating steel drum with steel spheres.
Question 2: A concrete cylinder fails at 3,800 psi at 28 days when the specified strength is 4,000 psi. What is the appropriate inspector action?
- Accept the concrete since it is close to specification
- Immediately reject all concrete placed that day
- Document the results and notify the engineer of record (Correct answer)
- Require a core sample from the structure before any action
Correct answer: Document the results and notify the engineer of record
The inspector must document the failing results and notify the engineer of record, who will determine if further investigation or remediation is required.
Question 3: Which ASTM standard governs the Standard Test Method for Penetration of Bituminous Materials?
- ASTM D 1586
- ASTM D 5 (Correct answer)
- ASTM D 4318
- ASTM D 698
Correct answer: ASTM D 5
ASTM D 5 is the standard test method for penetration of bituminous materials, measuring asphalt consistency by needle penetration depth.
Question 4: When testing soil for Proctor density, what does the term 'optimum moisture content' refer to?
- The moisture content at which soil becomes saturated
- The moisture content that achieves the maximum dry density (Correct answer)
- The natural in-situ moisture of the undisturbed soil
- The moisture content required for compaction equipment to operate
Correct answer: The moisture content that achieves the maximum dry density
Optimum moisture content is the water content at which a given compactive effort produces the maximum dry unit weight of a soil.
Question 5: A Marshall stability test is primarily used to evaluate which type of construction material?
- Portland cement concrete mixes
- Hot mix asphalt pavement (Correct answer)
- Stabilized subbase materials
- Structural steel connections
Correct answer: Hot mix asphalt pavement
The Marshall stability test evaluates the load-carrying capacity and flow characteristics of compacted hot mix asphalt specimens.
Question 6: What is the purpose of performing a flat and elongated particle test on coarse aggregate?
- To determine the aggregate's resistance to freeze-thaw cycles
- To measure the percentage of particles exceeding shape ratio limits (Correct answer)
- To evaluate aggregate surface texture for bonding
- To classify aggregate according to geological origin
Correct answer: To measure the percentage of particles exceeding shape ratio limits
Flat and elongated particle tests identify the percentage of aggregate particles whose longest dimension exceeds a specified ratio to the shortest dimension, as such particles can reduce pavement performance.
Question 7: Which field test is used to estimate the in-place density of asphalt pavement without destructive sampling?
- Sand cone test
- Nuclear density gauge (Correct answer)
- Rubber balloon method
- Drive cylinder method
Correct answer: Nuclear density gauge
The nuclear density gauge uses gamma radiation to non-destructively measure the in-place density and moisture content of compacted asphalt or soil.
CPII Material Testing 2
What does the Los Angeles Abrasion test measure for aggregates?