Materials Finer Than No. 200 Sieve (Washing Test) Flashcards

Which ASTM standard governs the test for materials finer than the 75-µm (No. 200) sieve in mineral aggregates by washing?

Answer: ASTM C117

ASTM C117 is the standard test method for materials finer than 75-µm (No. 200) sieve in mineral aggregates by washing.

What is the minimum sample size for a washing test on a fine aggregate (maximum size 3/8 in.) per ASTM C117?

Answer: 300 g

ASTM C117 requires a minimum sample mass of 300 g for fine aggregate with a maximum size of 3/8 in.

During the ASTM C117 washing test, the aggregate is washed over which sieve to capture all fine material?

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.

After washing, the retained aggregate must be dried to a constant mass at what temperature range?

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.

The percentage of material finer than the No. 200 sieve by washing is calculated using which formula?

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.

Which type of material is primarily removed during the ASTM C117 washing procedure that could not be removed by dry sieving alone?

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.

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?

Answer: 2.6%

(498 − 485) / 498 × 100 = 13/498 × 100 = 2.61%, which rounds to 2.6%.