Los Angeles Abrasion Testing Flashcards
7 cards from real ATT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Los Angeles Abrasion Testing flashcards as text
How many steel balls (charge) are used for ASTM C131 Grading A?
Answer: 12 balls
Grading A in ASTM C131 requires a charge of 12 steel balls weighing 5,000 ± 25 g.
What is the standard number of revolutions for the LA abrasion test on aggregates tested per ASTM C131?
Answer: 500 revolutions
The standard test per ASTM C131 requires exactly 500 revolutions of the LA machine drum.
The Los Angeles abrasion loss is expressed as:
Answer: The mass passing the No. 12 sieve divided by original mass × 100
LA abrasion loss (%) = (mass passing the No. 12 sieve ÷ original sample mass) × 100.
ASTM C535 is used instead of ASTM C131 when aggregate is:
Answer: Larger than 1½ inch (37.5 mm)
ASTM C535 covers larger aggregates with particles greater than 1½ in. (37.5 mm), while C131 covers smaller sizes.
After the LA abrasion test, the aggregate and charge are separated using a sieve with an opening size of:
Answer: No. 12 (1.70 mm)
The material is removed from the machine and sieved over a No. 12 (1.70 mm) sieve to determine loss.
The inside diameter of the Los Angeles abrasion machine drum is approximately:
Answer: 711 mm (28 in.)
The LA machine drum has an inside diameter of 711 mm (28 in.) and an inside length of 508 mm (20 in.).
When preparing a grading B sample for ASTM C131, which sieve sizes define the retained fractions?
Answer: 3/4 in. to 1/2 in. and 1/2 in. to 3/8 in.
Grading B uses material retained between 3/4–1/2 in. and 1/2–3/8 in. sieves with a total mass of 2,500 g each fraction.