Concrete @ your Fingertips

Riffle box
A sample divider (riffle box) is the most convenient method to reduce a bulk sample of aggregate to a smaller quantity for testing. The riffle box  is designed so that material poured in the top is divided approximately equally and diverted to two sides; material to one side of the box is discarded and the remainder tested or divided to a smaller sample. Coarse aggregates may be divided while damp, but fine aggregate should be surface-dry.

Acknowledgement: Concrete Society