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ASTM International · Aggregate · Laboratory test
ASTM C131: Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine
The Los Angeles abrasion test — steel spheres and a rotating drum that measure how much an aggregate breaks down under impact and wear, the toughness check for base course, ballast, and pavement aggregate.
| Designation | ASTM C131 |
| Setting | Laboratory |
| Service line | Construction Materials Testing |
Testing is performed to the current edition of ASTM C131 referenced by your project specification. This page is a plain-language overview, not a substitute for the published standard.
What the ASTM C131 test measures
ASTM C131 is the Los Angeles abrasion test. A graded charge of coarse aggregate is tumbled in a steel drum with a set of steel spheres for 500 revolutions, and the percentage of material that breaks down to pass the No. 12 sieve is the LA abrasion loss. It measures toughness: resistance to impact, crushing, and wear.
Base course, railroad ballast, surface treatment stone, and concrete and asphalt aggregate are all specified with a maximum LA loss because an aggregate that degrades under construction traffic and rollers becomes fines, and fines change everything the layer was designed to do.
How the ASTM C131 test works, step by step
The sample is washed, oven dried, and built to one of the standard gradings, A through D, that best matches the material's actual gradation. The corresponding number of steel spheres is added, the drum is rotated at 30 to 33 rpm for 500 revolutions, and the material is removed and sieved over the No. 12. The loss is the mass passing the No. 12 divided by the original mass, as a percentage. Larger aggregate is tested under ASTM C535.
What the numbers mean
Hard igneous rock and quartzite may lose 10 to 20 percent. Good limestones run 20 to 35 percent. Soft or weathered rock exceeds 40 percent. Common specification limits are 40 to 50 percent for concrete and base aggregate and 35 percent or less for ballast and high-friction surface courses. The value is a source property; it should not change unless the quarry ledge does.
What can throw the result off
Testing the wrong grading for the material, worn or under-mass spheres, and a drum with a worn shelf all shift the result. Drum condition and sphere mass are verification items in the laboratory quality system.
Common questions about ASTM C131
Is LA abrasion the same as soundness?
No. LA abrasion measures mechanical toughness. Soundness under ASTM C88 measures resistance to weathering through sulfate crystallization. Specifications often require both.
Can the test be run on recycled concrete aggregate?
Yes, and it is one of the standard qualification tests for recycled base, where losses tend to run higher than virgin stone.
How we help with ASTM C131 testing
Our laboratory runs LA abrasion as part of aggregate source approval and periodic verification, with results reported against the specification limit and the source history so a change in rock quality is caught early.
Scheduling & proposals
Need ASTM C131 testing?
Call for same-day dispatch questions, or send project documents for a written proposal.