APPENDIX-I SAMPLING AGGREGATE FROM STOCKPILES OR TRANSPORTATION UNITS AND FEW FUNDAMENTAL DEFINITIONS

 APPENDIX-I

SAMPLING AGGREGATE FROM STOCKPILES OR TRANSPORTATION

UNITS AND FEW FUNDAMENTAL DEFINITIONS

1. Scope:

In some Situations, it is mandatory to sample aggregates that have been stored in stockpiles or loaded into rail cars, barges or trucks. In such cases, the procedure should ensure that segregation does not introduce a serious bias in the results.

Sampling Aggregates,Standard Practice for Sampling Aggregates,Standard Practice for Sampling Aggregates D75/D75M,

2. Sampling from Stockpiles:

In sampling material from stockpiles it is very difficult to ensure unbiased samples, due to the

segregation which often occurs when material is stockpiled, with coarser particles rolling to the

outside base of the pile. For coarse or mixed coarse and fine aggregate, every effort should be made

to develop a separate, small sampling pile composed of materials drawn from various levels and

locations in the main pile after which several increments may be combined to compose the field

sample.

Samples from stockpiles should be made up of at least three increments taken from the top third, at

the mid-point and at the bottom third of the volume of the pile. A board shoved vertically into the

pile just above the sampling point aids in preventing further segregation. In sampling stockpiles of

fine aggregate, the outer layer, which may have become segregated, should be removed and the

sample taken from the material beneath. Sampling tubes, approximately 30 mm (1.25 in.) min.

diameter by 2 m (6 ft) min. length, may be inserted into the pile at random locations to extract a

minimum of five increments of materials to form the sample.

3. Descriptions of Terms:

Field sample: a quantity of the material to be tested of sufficient size to provide an acceptable

estimate of the average quality of a unit.

Lot: a sizeable isolated quantity of bulk material from a single source, assumed to have been

produced by the same process (for example, a day's production or a specific mass or volume).

Test portion: a quantity of the material of sufficient size extracted from the larger field sample by a

procedure designed to ensure accurate representation of the field sample and thus of the unit

sampled.

Unit: a batch or finite subdivision of a lot of bulk material (for example, a truck load or a specific

area covered).

4. Test Unit, Size and Variability:

The unit to be represented by a single field sample should neither be so large as to mask the effects

of significant variability within the unit nor be so small as to be affected by the inherent variability

between small portions of any bulk material.

Significant variability with a lot of material, where it might exist, should be indicated by statistical

measures, such as the standard deviation between units selected at random from within the lot.