The process of reducing a representative sample to a convenient size, or of dividing a sample into two or more smaller samples for testing, is called quartering. This is a non-mechanical method of reducing a sample.
Steps or Procedure for Quartering
Place the original sample in the center of a clean, dry, steel plate or other hard, smooth, non-absorptive surface.
Thoroughly mix the aggregate and using a scoop or any suitable tool, and form a cone-shaped pile.
Uniformly flatten the pile until the diameter is approximately equal to four to eight times the thickness.
With a large trowel or other suitable tool, divide the sample in half by vertically passing the tool through the center of the pile. In a similar manner divide each of these halves into two parts, thus quartering the sample.
Combine diagonally opposite quarters of the material into two samples. Store one of these two halves. If the remaining material still weighs too much, repeat the entire quartering process until the proper test sample size is obtained.
This method of sample reduction is employed when a mechanical splitter is not available.
Accuracy in quartering is most easily attained, in the case of fine and all in aggregate, with damp material.