Sampling of Aggregates AASHTO T-2-91 - New Mexico Department ...

Aggregate T-2 January 2012
3. Obtain increments as required. The increments combined shall meet or exceed the
minimum mass described in No. 2 above. Again, locations for incremental samples should
be determined using random number methodology. Windrow and Roadway samples
require one (1) increment each. Flowing Stream/Bin, Conveyor Belt, and Stockpile
samples require three (3) increments each.
4. Place sample in suitable container. Transport container shall be constructed to prevent
contamination, loss of material, loss of moisture, and contain fines or dust and prevent
damage to contents from mishandling during shipment. Cloth bags are commonly used for
aggregate. For material containing significant quantities for fines or dust, an alternate
container such as a can or box may be more appropriate, in order to minimize loss of
material.
5. Label sample properly. Minimum information shall include project I.D., name of sampler,
sample location, date sampled, description of material and purpose of sample (tests
required). Labels shall not smudge or run when wet and be affixed to the container in a way
that it will not become detached or lost.
Methods:
A. Flowing Aggregate Stream (Belt or Bin Discharge): (4.3.1)
1. Sample entire cross-section of discharge. It will probably be necessary to use a
sampling box or a pan on rails beneath the discharge to intercept the flowing aggregate
stream. Never attempt to intercept the stream with a shovel or a scoop, as this can cause
serious injury. Obtain three approximately equal increments.
2. Avoid sampling the initial discharge or final few tons of aggregates (Note 3).
Sampling the initial and/or the final portion of material increases the chances of
obtaining a segregated sample. Additionally, bins should be kept as full as possible
during the process to minimize segregation.
B. Conveyor Belt: (4.3.2)
1. Stop Conveyor. This is necessary for safety as well as for proper sampling technique.
2. Insert a template conforming to the shape of the conveyor belt. A template shall be
inserted perpendicular to the belt at a spacing that yields the desired increment of
material. Three increments are required to meet the mass in Table 1.
3. Collect all material inside the template. Avoid spilling any material and collect all
fines with a scoop, shovel, dustpan, and brush into a suitable container.
C. Roadway: (4.3.4)
1. Use template to mark area to be sampled. Obtain one sample, at a random location,
which totals the minimum mass in Table 1.
2. Sample the full depth of the material. This helps ensure representative material with
minimal segregation.
3. Avoid contaminating sample with underlying material.
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