For testing aggregates for resistance to abrasion. It consists of a disc rotating about a shaft connected to a reduction gear box coupled to a motor. The disc rotates at 28030 revolutions per minute. Under the rotating disc there is a tray with an outlet to facilitate the removal of sand. Two conical hoppers are mounted on a bracket. An arrangement is made to start and stop the flow of sand. Two containers with weights are supplied to keep the specimen pressed against the rotating disc. Suitable for operation on 220 volts, 50 cycles, A.C.supply.