LimsPulse
Construction materials testing

Los Angeles Abrasion Machine

A rotating steel drum in which coarse aggregate is tumbled with steel balls for a fixed number of revolutions. The percentage worn down to fines (the LA abrasion value) measures resistance to abrasion and impact.

  • Construction materials testing
  • Road and highway construction
  • Railways
  • Quarries
  • Academic labs
Photo of a Los Angeles Abrasion Machine
Photo: Tanvir Anjum Adib, CC BY-SA 4.0 (cropped), via Wikimedia Commons
LEARN & PRACTICE

Test your LA abrasion machine knowledge

Multiple-choice questions

Pick an answer to see whether you are right and why.

  1. Q1. At what speed does the Los Angeles drum rotate?

    basic

  2. Q2. Which sieve is used to determine the loss in the LA abrasion test?

    basic

  3. Q3. 5000 g of aggregate leaves 3920 g retained on the test sieve after 500 revolutions. What is the LA abrasion value?

    intermediate

  4. Q4. For grading A, how many steel spheres make up the abrasive charge?

    intermediate

  5. Q5. 157 revolutions are counted in 5 minutes. What is the drum speed, and is it acceptable?

    intermediate

  6. Q6. Spheres that have worn below their minimum mass would make LA values:

    advanced

Viva questions

Think of your answer first, then open it to compare.

  1. 1. What is the role of the shelf inside the LA drum?

    The shelf lifts the aggregate and steel spheres and drops them on each revolution, adding impact to the grinding action, so the test reflects both abrasion and breakage.

  2. 2. What do you check in a drum speed and abrasive charge check?

    Count revolutions over a timed period to confirm 30–33 rpm, confirm the counter stops at the set number, weigh each sphere against the individual mass range and the total charge for each grading, and check drum and shelf dimensions.

  3. 3. How do the LA abrasion and aggregate impact tests differ?

    The impact test applies 15 heavy blows to a small single-size sample and measures toughness. The LA test tumbles a larger graded sample with steel spheres for hundreds of revolutions and measures resistance to combined abrasion, attrition and impact. Both are used, with separate limits in IS 383.

In LimsPulse · Calibration Management

Keep every LA abrasion machine in control: usage logs, calibration and maintenance schedules, and automatic blocking of overdue instruments.

See how