ATT Fine Aggregate Quality Tests 3 — Questions and Answers
Question 1: What is the minimum sample mass required for a sieve analysis (ASTM C136) of fine aggregate?
- 300 g (Correct answer)
- 100 g
- 500 g
- 1000 g
Correct answer: 300 g
ASTM C136 requires a minimum sample mass of 300 g for fine aggregate sieve analysis to ensure representative results.
Question 2: Which ASTM standard governs the mortar-making properties test used to evaluate fine aggregate with elevated organic content?
- ASTM C87 (Correct answer)
- ASTM C40
- ASTM C117
- ASTM C88
Correct answer: ASTM C87
ASTM C87 compares the compressive strength of mortar made with the suspect aggregate to mortar made with washed aggregate to determine if organics are harmful.
Question 3: The acceptable fineness modulus range for fine aggregate used in concrete typically falls between:
- 2.3 and 3.1 (Correct answer)
- 1.5 and 2.0
- 3.1 and 4.0
- 4.0 and 5.0
Correct answer: 2.3 and 3.1
ACI 301 and ASTM C33 specify that the fineness modulus of fine aggregate should be between 2.3 and 3.1 for concrete applications.
Question 4: When performing the bulk density (unit weight) test per ASTM C29 on fine aggregate using rodding, how many layers are used?
- 3 layers, each rodded 25 times (Correct answer)
- 2 layers, each rodded 50 times
- 5 layers, each rodded 10 times
- 1 layer, rodded 75 times
Correct answer: 3 layers, each rodded 25 times
ASTM C29 rodding procedure uses three equal layers, each consolidated by 25 strokes of the tamping rod.
Question 5: ASTM C123 is used to determine the percentage of which material in fine aggregate?
- Lightweight pieces (Correct answer)
- Clay lumps
- Organic matter
- Chert particles
Correct answer: Lightweight pieces
ASTM C123 uses a heavy liquid (such as zinc chloride solution) to float and separate lightweight pieces from the aggregate.
Question 6: During the ASTM C88 soundness test, how many cycles of immersion and drying are typically performed?
- 5 cycles (Correct answer)
- 3 cycles
- 10 cycles
- 7 cycles
Correct answer: 5 cycles
The standard soundness test procedure performs 5 cycles of immersion in sulfate solution followed by oven drying.
Question 7: For ASTM C40 (organic impurities), the sodium hydroxide solution used has a concentration of:
- 3% NaOH by mass (Correct answer)
- 10% NaOH by mass
- 1% NaOH by mass
- 5% NaOH by mass
Correct answer: 3% NaOH by mass
ASTM C40 specifies a 3% sodium hydroxide (NaOH) solution by mass to extract organic compounds from the aggregate for color comparison.
ATT Fine Aggregate Quality Tests 3
What is the minimum sample mass required for a sieve analysis (ASTM C136) of fine aggregate?