THE DESIGN AND CONSTRUCTION OF A CIRCULAR WEAR TRACK

The report describes a test apparatus For Determining The Wear Resistance of Pavement Surface Materials. The apparatus employs a high torque, low speed, hydraulic vane motor as a direct rotating drive for the axle-wheel assemblies. Tire path radius change is provided by a reciprocating vertical hydraulic cylinder connected to a rack and pinion mechanism. The rate of path radius change relative to tire speed is controlled by an adjustable flow divider. A variable displacement axial piston pump, driven by an electric motor permits infinite adjustment of the rotational speed. The mean tire path diameter is fifteen feet, with a radius change capability of six inches. Features of the apparatus include simplicity of design, high expected reliability, minimal maintenance, protection against overloads during start up and shutdown, and ease of control.