Which statement is true regarding splitting large samples?

• A. When samples are large, it is recommended that they be split using mechanical methods.
• B. Draindown at production temperatures should not exceed 3%.
• C. Surfaces that will be exposed to hot mix asphalt should be coated with petroleum based release agents prior to use.
• D. In the incremental method, the entire sample should be turned over itself at least three times.

Answer: (A)

When samples are large, the aim is to produce a sub-sample that truly represents the whole batch. Mechanical splitting does this consistently by dividing the bulk into equal portions using devices like riffle dividers, cone splitters, or rotating splitters, and then combining those portions to form a representative sample. This minimizes bias from manual cutting, which can skew the distribution of aggregates, moisture, and temperature in the sub-sample. In asphalt testing, keeping the sub-sample representative is crucial for accurate test results, especially when dealing with coarse materials and heat-sensitive binder.

The other statements don’t address obtaining a representative split. Draindown limits pertain to a different test about binder loss, coating surfaces with petroleum-based release agents can contaminate the sample, and the described turning method relates to a mixing technique rather than a proper split of a large bulk.