What Does the Los Angeles Abrasion Test Measure?
A durability check that predicts how aggregate holds up under repeated wear
Simulating real-world wear in a lab
Aggregate used in pavements and bases is subjected to repeated abrasion and impact over its service life — from traffic loading, compaction equipment, and handling during production and placement. The LA abrasion test simulates this by tumbling a sample with steel spheres in a rotating drum, producing a controlled, repeatable measure of how much the material degrades.
Why durability matters beyond initial strength
An aggregate can look strong initially but break down faster than expected under the combined abrasion and impact it experiences once in service, generating fines that can clog drainage layers or reduce a pavement structure's designed performance over time. The LA abrasion result gives specifiers a way to screen for this before the material is ever placed.
How the result is applied
Project specifications set a maximum acceptable LA abrasion percent-loss for a given application — surface-course aggregate exposed to the most wear typically has a stricter (lower) limit than base-course or fill material used deeper in the structure, though the exact limits always come from the applicable specification rather than a single universal number.
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Sources
ASTM C131 / C535
Standard Test Methods for Resistance to Degradation of Small-Size / Large-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine.