Los Angeles Abrasion Value

The Los Angeles abrasion test, per IS 2386 Part 4, measures an aggregate's resistance to the combined abrasion, attrition and impact it experiences in service. A graded sample is rotated in the Los Angeles machine drum with a charge of steel spheres for a set number of revolutions; the LA value is the percentage of material worn down below 1.7 mm. A lower LA value indicates a harder, more wear-resistant aggregate.

It is the principal hardness/durability acceptance test for pavement and concrete aggregates and for railway ballast. MORTH/IS limits are typically ≤30% for bituminous wearing courses and concrete, ≤40-50% for lower pavement layers. Reported with ACV and AIV, it screens out aggregates that would polish or degrade under traffic, losing skid resistance and generating fines.