The test provides a measure of the resistance of aggregate to surface wear by abrasion. The machine, formerly named “Dorry abrasion machine”, consists of a circular cast iron grinding lap 600 mm dia. which rotates in a horizontal plane at a speed of 28/30 r.p.m. The abrasive sand is fed across the surface of the specimen samples through a special funnel. The machine is supplied complete with two specimen moulds, two trays, two flat plates, weights and clamps.