ATT Materials Finer Than No. 200 Sieve (Washing Test) 2 — Questions and Answers
Question 1: For coarse aggregate with a nominal maximum size of 1 in., what minimum sample mass is required for the ASTM C117 washing test?
- 500 g
- 1000 g
- 2000 g (Correct answer)
- 5000 g
Correct answer: 2000 g
ASTM C117 requires a minimum 2000 g (2 kg) sample for coarse aggregate with a 1-in. nominal maximum size.
Question 2: When combining results of the ASTM C117 wash test with a dry ASTM C136 sieve analysis, how is the total percent passing the No. 200 sieve reported?
- Only the dry sieve result is used
- Only the wash test result is used
- The wash test value is used as it captures more fines than dry sieving (Correct answer)
- The average of both values is reported
Correct answer: The wash test value is used as it captures more fines than dry sieving
The ASTM C117 wash test captures fines adhered to particles that dry sieving misses, so it yields a higher and more accurate value for material finer than No. 200.
Question 3: What is the purpose of using a large enough container during the washing operation in ASTM C117?
- To prevent aggregate from absorbing too much water
- To allow complete immersion and vigorous agitation without losing aggregate over the rim (Correct answer)
- To slow the rate of washing so fines settle before decanting
- To maintain a constant water temperature during washing
Correct answer: To allow complete immersion and vigorous agitation without losing aggregate over the rim
Using a container large enough to submerge the sample fully and agitate vigorously prevents coarse particles from spilling over the rim and being counted as fines.
Question 4: How many times should washing and decanting be repeated per ASTM C117 until the process is considered complete?
- Exactly once
- Exactly three times
- Until the wash water is clear (Correct answer)
- Until the No. 200 sieve shows no visible fines
Correct answer: Until the wash water is clear
ASTM C117 requires repeated washing and decanting until the wash water is clear, indicating all fines have been removed.
Question 5: Which sieve must be placed beneath the No. 200 sieve to prevent damage during the ASTM C117 wash procedure?
- No. 100 sieve (Correct answer)
- No. 50 sieve
- No. 16 sieve
- No. 4 sieve
Correct answer: No. 100 sieve
A No. 100 sieve is placed beneath the No. 200 sieve to protect it from damage caused by the force of the wash water stream.
Question 6: What would cause a higher-than-actual result in the ASTM C117 wash test?
- Incomplete drying of the sample before the initial weighing (Correct answer)
- Failing to nest the No. 100 sieve under the No. 200
- Washing the sample more times than necessary
- Using distilled water instead of tap water
Correct answer: Incomplete drying of the sample before the initial weighing
If the sample is not dried to constant mass before weighing, the initial mass A is artificially high, inflating the calculated percentage of fines.
Question 7: ASTM specifications for concrete aggregates typically limit material finer than No. 200 in fine aggregate to a maximum of what percentage (for concrete subject to abrasion)?
- 1.5%
- 2.0%
- 3.0% (Correct answer)
- 5.0%
Correct answer: 3.0%
ASTM C33 limits material finer than No. 200 in fine aggregate to 3.0% for concrete subject to abrasion, and 5.0% for other concrete.
ATT Materials Finer Than No. 200 Sieve (Washing Test) 2
For coarse aggregate with a nominal maximum size of 1 in., what minimum sample mass is required for the ASTM C117 washing test?