Los Angeles Abrasion Test: Procedure and Equipment Guide

What Does the Test Measure?

The Los Angeles (LA) Abrasion test measures the resistance of coarse aggregate to fragmentation by abrasion and impact. Steel spheres (the "charge") tumble with the aggregate sample inside a rotating steel drum, simulating the degradation aggregate undergoes during handling, compaction, and traffic loading.

Results are reported as the LA Abrasion Loss (%) — the percentage of material finer than 1.70 mm after the test relative to the original sample mass. Lower values mean harder, more durable aggregate.

ASTM C131 covers aggregate sizes up to 37.5 mm; ASTM C535 covers larger aggregate (37.5–75 mm). The European equivalent is EN 1097-2.

Equipment

• Los Angeles Abrasion Machine: Steel drum, 711 mm internal diameter × 508 mm length, rotating at 30–33 rpm. Fitted with a shelf 89 mm wide projecting inward.
• Steel Charge (Spheres): 46.0–47.6 mm diameter spheres. Number of spheres depends on grading designation (A–D for C131, E–G for C535).
• Sieves: As required per grading — 1.70 mm sieve for measuring loss.
• Balance: Accurate to 1 g.

Procedure Summary

1. Wash and oven-dry the aggregate sample. Sieve to the appropriate grading designation.
2. Place aggregate and the required number of steel spheres into the drum.
3. Rotate for 500 revolutions at 30–33 rpm (ASTM C131) or 1000 revolutions (ASTM C535).
4. Remove material and sieve over 1.70 mm. Wash the retained fraction and oven-dry.
5. Calculate: LA Loss (%) = [(M₁ − M₂) / M₁] × 100 where M₁ = original mass, M₂ = mass retained on 1.70 mm sieve.

Acceptance Limits