ATT Materials Finer Than No. 200 Sieve (Washing Test) 1 — Questions and Answers
Question 1: Which ASTM standard governs the test for materials finer than the 75-µm (No. 200) sieve in mineral aggregates by washing?
- ASTM C136
- ASTM C117 (Correct answer)
- ASTM C127
- ASTM C131
Correct answer: ASTM C117
ASTM C117 is the standard test method for materials finer than 75-µm (No. 200) sieve in mineral aggregates by washing.
Question 2: What is the minimum sample size for a washing test on a fine aggregate (maximum size 3/8 in.) per ASTM C117?
- 100 g
- 200 g
- 300 g (Correct answer)
- 500 g
Correct answer: 300 g
ASTM C117 requires a minimum sample mass of 300 g for fine aggregate with a maximum size of 3/8 in.
Question 3: During the ASTM C117 washing test, the aggregate is washed over which sieve to capture all fine material?
- No. 100 (150 µm)
- No. 200 (75 µm) (Correct answer)
- No. 325 (45 µm)
- No. 50 (300 µm)
Correct answer: No. 200 (75 µm)
The wash water and suspended fines pass through the No. 200 (75-µm) sieve, retaining only particles coarser than 75 µm.
Question 4: After washing, the retained aggregate must be dried to a constant mass at what temperature range?
- 90 ± 5°C (194 ± 9°F)
- 110 ± 5°C (230 ± 9°F) (Correct answer)
- 130 ± 5°C (266 ± 9°F)
- 150 ± 5°C (302 ± 9°F)
Correct answer: 110 ± 5°C (230 ± 9°F)
ASTM C117 specifies drying the washed sample to constant mass at 110 ± 5°C (230 ± 9°F), the standard oven-dry temperature for aggregates.
Question 5: The percentage of material finer than the No. 200 sieve by washing is calculated using which formula?
- (A − B) / A × 100 (Correct answer)
- (B − A) / B × 100
- (A + B) / A × 100
- (A − B) / B × 100
Correct answer: (A − B) / A × 100
The formula (A − B) / A × 100 gives the percent passing No. 200, where A is the original dry mass and B is the dry mass after washing.
Question 6: Which type of material is primarily removed during the ASTM C117 washing procedure that could not be removed by dry sieving alone?
- Coarse particles bonded by cement
- Clay coatings and silt adhering to larger particles (Correct answer)
- Organic materials floating on the surface
- Oversized particles larger than 1.5 in.
Correct answer: Clay coatings and silt adhering to larger particles
The washing test removes clay coatings and silt that adhere to larger particles and cannot be separated by dry sieving alone.
Question 7: If the original oven-dry mass of a fine aggregate sample is 498 g and the oven-dry mass after washing is 485 g, what is the percentage of material finer than the No. 200 sieve?
- 2.0%
- 2.6% (Correct answer)
- 2.8%
- 3.2%
Correct answer: 2.6%
(498 − 485) / 498 × 100 = 13/498 × 100 = 2.61%, which rounds to 2.6%.
ATT Materials Finer Than No. 200 Sieve (Washing Test) 1
Which ASTM standard governs the test for materials finer than the 75-µm (No. 200) sieve in mineral aggregates by washing?