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ASTM International · Aggregate · Field test
ASTM D75: Sampling Aggregates
How a representative aggregate sample is taken from a stockpile, conveyor belt, truck, or roadway — the practice that determines whether every gradation and quality test downstream means anything.
| Designation | ASTM D75 |
| Setting | Field |
| Service line | Construction Materials Testing |
Testing is performed to the current edition of ASTM D75 referenced by your project specification. This page is a plain-language overview, not a substitute for the published standard.
What ASTM D75 covers
ASTM D75 is the practice for sampling aggregates. It describes how to take a sample from a stockpile, a conveyor belt, a bin or truck, a roadway base, or a production stream so that the sample represents the material being judged. It is not a test method. Every gradation, specific gravity, abrasion, and soundness result reported downstream is only as good as the sample it came from, which is why accreditation scopes list it and why specifications require it.
Stockpiles segregate. Coarse particles roll to the bottom and outside, fines stay near the top and center, and the surface dries while the interior stays wet. A sample scooped off the face of a pile is almost never the material that will go into the mix.
What the practice requires
The preferred sampling points are the conveyor belt, using a template to remove the full belt cross-section, or the discharge stream, using a sampling device that cuts across the entire flow. Stockpile sampling uses a loader to expose a fresh face or a sampling tube, taking increments from the top, middle, and bottom third and avoiding the segregated outer layer. Minimum sample sizes are set by nominal maximum aggregate size so there is enough material for the tests to be run.
Samples are combined, labeled with source, product, location, date, and sampler, and reduced to test size in the laboratory under ASTM C702.
Why it matters to your project
A failing gradation that came from a bad sample costs a rejected load or an argument with the supplier; a passing gradation from a bad sample lets out-of-spec material into the work. Both are avoided by sampling correctly and documenting how it was done. When results are disputed, the sampling record is the first thing examined.
Common questions about ASTM D75
Who should take the sample?
A technician trained in the practice, whether from the testing laboratory, the producer, or the agency. Many specifications require the testing agency to sample or witness sampling.
How much material is needed?
Depends on maximum particle size and the tests to be run; a full source qualification on 1-inch stone can need 100 pounds or more. We advise on quantity before sampling.
How we help with ASTM D75 sampling
Our field technicians sample at the plant, belt, or stockpile in accordance with D75, document the location and method, and deliver the sample to our laboratory with a chain of custody so the test results are defensible.
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